[Monkee]

So this is something i've been wondering for a while while it seems like the TPS governs the amount of retard or advance depending on load and RPM. For many CDI bikes i know they use some kind of air suction to determine how much timing to put into it.

I've heard some people just forfeiting the TPS altogether and not getting any sort of pinging or knock. Does anyone have a more in depth explanation or perhaps experience?

I'd like to learn more about the role the TPS plays in the ignition since the older bullets didnt have a TPS but were still TCI ingition i believe?

[SteveThackery]

What does TCI stand for?

The TPS is used, along with the MAP sensor, to determine the load on the engine. The ECU then determines the optimum amount of fuel to inject and the optimum ignition timing.  The engine oil temperature sensor is also taken into account.

I've never done it, but I would strongly suspect that disconnecting the TPS will illuminate the MIL and put the bike into "get you home" mode.

By that, I mean that the ECU can estimate the engine load without the help of the TPS. However, the load estimation will be less accurate, so the bike should still run but the mixture and ignition timing will be less "perfect" than when all sensors are working.

Most of this is driven by emission regulations. The information provided by the various sensors allows the ECU to operate the engine in a way that minimises emissions.

This article gives a great overview, explaining the differences between alpha-n speed-density algorithms:

https://www.holley.com/blog/post/fuel_injection_fundamentals_understanding_the_three_different_fueling_strategies/#:~:text=The%20Alpha-N%20style%20of%20engine%20tuning%20looks%20at,a%20boosted%20motor%20of%20any%20type%2C”%20says%20Flynn.

[tooseevee]

What does TCI stand for?

           Transistor Controlled Ignition or Transistor Coil Ignition. My AVL has TCI (the green one). I think later ones were CDI?

[Monkee]

           Transistor Controlled Ignition or Transistor Coil Ignition. My AVL has TCI (the green one). I think later ones were CDI?

As far I can see there were none that were CDI? I may be wrong. but does your AVL have a TPS?

[Adrian II]

Are we talking about an Indian market 500 UCE Bullet fitted with a carburettor from the factory, here?

These were on sale alongside EFI models in India until a few years ago, but in this case the CV carbs used DO have TPS. There's no ECU in the fuel-injected sense, but the TPS is linked to the TCI ignition module on these bikes. Someone in India was marketing the TPS carbs as a kit to retro-fit to EFI models.

If the TCI is designed to work in tandem with a TPS, leave it alone, or fit the TCI off an earlier model, e.g the 500 AVL Machismo or Electra-X.

Royal Enfield (India) had three CDI ignition models in the range, the 2002 350 Electra, the A350 kick start Machismo and the 350 kick start Thunderbird, AFAIK the auto-advance was built into the CDI controller electronically, there's certainly no vacuum ignition control on these.

The AVL models came with CV carbs from the factory (apart from the Dell'Orto PHBHs fitted to early A350 Machismos) but no TPS, and definitely not on the after-market carburettors many of us are using.

A.

[tooseevee]

As far I can see there were none that were CDI? I may be wrong. but does your AVL have a TPS?

     I should have been clearer. I didn't mean later AVLs, I meant later Royal Enfields.

[SteveThackery]

As far I can see there were none that were CDI? I may be wrong. but does your AVL have a TPS?

Just a point - we're in the UCE forum here. I don't want us to get into a state of confusion. 

[Monkee]

Are we talking about an Indian market 500 UCE Bullet fitted with a carburettor from the factory, here?

These were on sale alongside EFI models in India until a few years ago, but in this case the CV carbs used DO have TPS. There's no ECU in the fuel-injected sense, but the TPS is linked to the TCI ignition module on these bikes. Someone in India was marketing the TPS carbs as a kit to retro-fit to EFI models.

If the TCI is designed to work in tandem with a TPS, leave it alone, or fit the TCI off an earlier model, e.g the 500 AVL Machismo or Electra-X.

Royal Enfield (India) had three CDI ignition models in the range, the 2002 350 Electra, the A350 kick start Machismo and the 350 kick start Thunderbird, AFAIK the auto-advance was built into the CDI controller electronically, there's certainly no vacuum ignition control on these.

The AVL models came with CV carbs from the factory (apart from the Dell'Orto PHBHs fitted to early A350 Machismos) but no TPS, and definitely not on the after-market carburettors many of us are using.

A.

Ah yes this is what i've seen as well. I was wondering if it was possible to fit a non TPS equipped carb like an Amal or Mikuni with the brown multicurve TCI and if that would have any negative effects, or if alternatives there were TCI ignition modules that didn't require a TPS but were also fitted on the UCEs

[Crabsapper]

My 2020 UCE C5 has been fitted with a Mikuni, as well as the wiring loom, stator and rotor from carbed bikes.
I've used both the green and brown TCI boxes, both work fine.
The green TCI has no TPS input, but the brown does. With the brown TCI fitted obviously the TPS is left disconnected, and the bike runs fine.....I can't tell the difference between that and the green. Both pull hard up to and past an indicated 80mph with no discernible difference in performance.
I was told the brown TCI defaults to a more retarded curve with the TPS disconnected, but I'm reluctant to accept that.
Current using the green as starting seems easier.

[Monkee]

My 2020 UCE C5 has been fitted with a Mikuni, as well as the wiring loom, stator and rotor from carbed bikes.
I've used both the green and brown TCI boxes, both work fine.
The green TCI has no TPS input, but the brown does. With the brown TCI fitted obviously the TPS is left disconnected, and the bike runs fine.....I can't tell the difference between that and the green. Both pull hard up to and past an indicated 80mph with no discernible difference in performance.
I was told the brown TCI defaults to a more retarded curve with the TPS disconnected, but I'm reluctant to accept that.
Current using the green as starting seems easier.

Oh Hey crabsapper! i ordered the parts im just waiting for them. Im thinking of trying out an OKO flatslide or a keihin round slide instead of the VM just because its easier to find repair kits and jetts for them in my area. For the throttle cables i orderd a venhill custom cable kit and will just build my own.

I wonder if theres anyone on the forum who has a definitive answer for the TCI's and TPS. I've read somewhere that on the carbed models the TPS acts like an on/off switch rather than a progressive linear taper kind of thing. i dont know how much truth is in that statement but i'd be a fun discussion to have.

[Monkee]

Also has anyone ever tried running CDI's on their UCE bikes? Reason why im asking is because i once talked to a mechanic who rigged up a dual CDI ignition for I believe was a virago or some other japanese V twin cruiser without a hiccup.

If i understand correctly the main difference between a CDI and TCI are the ingition coils needed? I think CDI calls for a higher resistance ignition coil?

[Adrian II]

The green TCI was a Mk2 version for the AVL originally, brown most likely for the UCE as the TPS on a carb is a later addition as explained above.

What would be the advantage on a UCE Bullet (assume carburettor fitted) from changing from TCI to CDI? There might be some Suzuki-type alternator stator "out there somewhere" with the CDI charging coil which would just happen to fit the Bullet mountings, but it sounds like a lot of hassle. The old AVL CDI igntions were battery-independent, is that what you'd be trying to achieve?

A.

[SteveThackery]

What would be the advantage on a UCE Bullet (assume carburettor fitted) from changing from TCI to CDI?

Probably none. Capacitor discharge ignition is better at lighting up a fouled plug due to its exceptionally fast rise time, hence their popularity on two-strokes. Inductive discharge ignition (which you call TCI) is better at igniting weak mixtures due to its relatively long duration, flaming spark.

Having used both on various cars and bikes over some 50 years, I can say that there is no discernible difference to me.

[Monkee]

Probably none. Capacitor discharge ignition is better at lighting up a fouled plug due to its exceptionally fast rise time, hence their popularity on two-strokes. Inductive discharge ignition (which you call TCI) is better at igniting weak mixtures due to its relatively long duration, flaming spark.

Having used both on various cars and bikes over some 50 years, I can say that there is no discernible difference to me.

To me the only real benefit is the availability of CDIs compared to TCIs in general. thinking way too ahead of myself but i just like knowing if and when i can no longer find OE parts i could rig something up from another bike's ignition.

[Monkee]

The green TCI was a Mk2 version for the AVL originally, brown most likely for the UCE as the TPS on a carb is a later addition as explained above.

What would be the advantage on a UCE Bullet (assume carburettor fitted) from changing from TCI to CDI? There might be some Suzuki-type alternator stator "out there somewhere" with the CDI charging coil which would just happen to fit the Bullet mountings, but it sounds like a lot of hassle. The old AVL CDI igntions were battery-independent, is that what you'd be trying to achieve?

A.

I was thinking if it was possible to forego the battery and be able to kickstart even when the battery was dead flat. But seems like i'd either have to have a custom stator made or find one that fits. But more pressing of my two questions is How much a difference would it be if i were to fit an AVL TCI into a UCE engine to be able to use non TPS equipped carbs

[Haggis]

I have an Amal with no tps on one of my 500 uce. Still need a battery for sparks though.

[Adrian II]

I was thinking if it was possible to forego the battery and be able to kickstart even when the battery was dead flat. But seems like i'd either have to have a custom stator made or find one that fits. But more pressing of my two questions is How much a difference would it be if i were to fit an AVL TCI into a UCE engine to be able to use non TPS equipped carbs

Probably not very much difference at all! Haggis makes a good point in that the carburettor conversions available for EFI versions of the UCE models use classic old-school carburettor types, either Amal or Mikuni, which have never had TPS and they run just fine, even using the EFI's engine control unit (ECU), which I understand DOES normally use a TPS.

Getting a Bullet OEM TCI to run battery-less is probably not an option, I tried replacing the battery on my old 500 AVL with a capacitor, but the alternator wasn't producing enough output at kick starting speeds to produce a spark. More recent alternators in these bikes have 18 coil stators instead of my old bike's 12 coils so might produce better output at lower speeds. For experimental purposes you could buy a suitable capacitor cheap enough and wire it in place of the battery if you wanted to prove me wrong.

A.

[Monkee]

Probably not very much difference at all! Haggis makes a good point in that the carburettor conversions available for EFI versions of the UCE models use classic old-school carburettor types, either Amal or Mikuni, which have never had TPS and they run just fine, even using the EFI's engine control unit (ECU), which I understand DOES normally use a TPS.

Getting a Bullet OEM TCI to run battery-less is probably not an option, I tried replacing the battery on my old 500 AVL with a capacitor, but the alternator wasn't producing enough output at kick starting speeds to produce a spark. More recent alternators in these bikes have 18 coil stators instead of my old bike's 12 coils so might produce better output at lower speeds. For experimental purposes you could buy a suitable capacitor cheap enough and wire it in place of the battery if you wanted to prove me wrong.

A.

Thats reassuring i guess it wouldn't really matter which TCI i decide to go with my conversion. The reason why i dont want to go the Hitchcock's conversion method is 1. shipping to my country is way more expensive than getting all the parts to replace it with OE components for the conversion 2. I want to keep the stock harness relatively unmolsted if i ever decide to swap back to EFI.

I saw a video somewhat recently of an indian mechanic swapping out the RR not sure what it was but he was able to start the bike without the battery nor capacitor at all. I believe its a RR unit that already has a capacitor in it? Video didnt have subtitles and i dont speak hindi so i wouldn't know. I tried to message their shop directly but they dont want to sell me just the RR unit.

[Adrian II]

I saw a video somewhat recently of an indian mechanic swapping out the RR not sure what it was but he was able to start the bike without the battery nor capacitor at all. I believe its a RR unit that already has a capacitor in it? Video didnt have subtitles and i dont speak hindi so i wouldn't know. I tried to message their shop directly but they dont want to sell me just the RR unit.

Quite possibly, if the newer alternators have a better output at low RPM it could work.

A.

[Haggis]

There is a capacitor built into the R/R unit but it's only there to smooth the voltage. Both my 17 and 18 euro 3 bikes have an external  capacitor wired across the positive and negative on R/R.

[Crabsapper]

But more pressing of my two questions is How much a difference would it be if i were to fit an AVL TCI into a UCE engine to be able to use non TPS equipped carbs

Haven't I already answered that question?

I want to keep the stock harness relatively unmolsted if i ever decide to swap back to EFI.

The stock EFI harness ECU plug won't fit the TCI, nor the stator connector as you need to change that too.
If you want to keep the option to swap back to EFI, keep the EFI ECU for ignition, as per the Hitchcocks method.
As has been shown, that works fine with the TPS disconnected.

[SteveThackery]

If you want to keep the option to swap back to EFI, keep the EFI ECU for ignition, as per the Hitchcocks method.
As has been shown, that works fine with the TPS disconnected.

Yes, that's what I was thinking. The best approach is to do the bare minimum necessary. Disconnect the injector and the TPS; remove the throttle body and fit a carb; job done, isn't it? Ultra-quick to revert.

I don't understand why you would want to ditch the existing ignition system and fit another. It won't work any better.

[Monkee]

Haven't I already answered that question?The stock EFI harness ECU plug won't fit the TCI, nor the stator connector as you need to change that too.
If you want to keep the option to swap back to EFI, keep the EFI ECU for ignition, as per the Hitchcocks method.
As has been shown, that works fine with the TPS disconnected.

You have and thanks. Yeah im aware the EFI harness wont work hence needing a different wiring harness. which im fine with so its this whole direct swap part per part. which i appriciate.

[Monkee]

Yes, that's what I was thinking. The best approach is to do the bare minimum necessary. Disconnect the injector and the TPS; remove the throttle body and fit a carb; job done, isn't it? Ultra-quick to revert.

I don't understand why you would want to ditch the existing ignition system and fit another. It won't work any better.

I could give hitchcock's method a try. but i dont know i guess in my head its easier to have System A vs System B binned separately and not have to faff about with converting wiring or converting it aside from its original design being a whole complete EFI system. Anyway the point of this thread is just to gather some ideas and info from more knowledgable people than myself. Another thing that bothers me with Hitchcock's method is i'd like to use an ammeter instead of disabling the MIL. I dont really mind taking a whole weekend or a day doing it.

[Crabsapper]

Trouble is, if you want a clean conversion, it's a good bit more work. If you want an Ammeter, you really need the appropriate loom.
If you want to go away from the ECU to a TCI, you need to change the rotor (EFI bike has a crank position sensor, not a trigger). This requires a stator change too, as they are different sizes.
You also need to buy or make a fuel pump blank for the tank, plus a tap.
There's a hatful of sensors and wiring tweaks on top, and if you've got ABS that will go too.
It took me a bit longer than a weekend!
Going backwards and forwards is certainly not a desirable thing!

[SteveThackery]

Forgive me, but I am not being rude. I just can't see what the point of all this is.

I can just about see why you might prefer a carb, but why go through all the pain of fitting a TCI when the existing ECU already makes perfectly good sparks?

Personally I wouldn't dream of changing a good EFI to a carb, because EFI works better. The fact that carbs cannot deliver sufficiently precise mixture control says it all.

[axman88]

Yes, that's what I was thinking. The best approach is to do the bare minimum necessary. Disconnect the injector and the TPS; remove the throttle body and fit a carb; job done, isn't it? Ultra-quick to revert.

I don't understand why you would want to ditch the existing ignition system and fit another. It won't work any better.

I think that one would also be removing the fuel pump, and blanking off the large opening in the bottom of their fuel tank with cover that included mounting opening(s) for a petcock for gravity fuel feed.  This is not trivial, especially since Hitchcocks seems to no longer offer the carb. retrofit kit.  Perhaps the blanking plate component is still available, but I can't find it.  And of course, the 02 sensor, temperature sensor, and MAPS (if equipped), would also be vestigial, and could be removed and blanked.

IF I did it, I would do a carb conversion on my C5 the hard way, including replacing the ECU with an alternate ignition for several reasons;
  - I just wouldn't feel right about taping over the MIL light with a piece of electrical tape and ignoring the fact that the ECU was living in a constant state of alarm, having lost contact with many of its sensors.
  -  I suspect that old ECU costs more power consumption than the simpler TCI, especially if one is still heating their vestigial 02 sensor.
  -  The ECU is worth quite a bit more than the TCI, like $250 vs. $50.  If I pull out good parts and cash them in via Ebay, I calculated I would come out a couple hundred dollars on the plus side, even after purchasing the appropriate rotor, the TCI and the carb.  I get to sell the ECU, the fuel pump, the multi-lobed EFI rotor, the throttle body, the injector, and various sensors as spares, all of which are fairly high dollar items, and are, I believe, increasing in value year by year, as is generally always the case with discontinued models.

There is a thread from a few years ago, wherein a knowledgeable member listed all the RE P/Ns needed to do a 500 EFI export conversion "the hard way".  I participated in the thread, but I don't recall the thread title.  This would have been around 2021 or thereabouts.

The blanking plate is the most difficult piece of the puzzle, at this point.  I'm thinking the better solution might  be to modify an IB Bullet tank to mount on my C5, and then sell the EFI tank, which would be another net financial gain.

Most of our members seem to be well heeled westerners, who don't even consider something as pedestrian as saving a few dollars, or selling their unused parts for cash.  Apparently most folks who reported doing the conversion forked over the $400 or so that Hitchcocks was charging for their conversion kit, put their takeout parts into a box on a high shelf, and end of story.  Carb. conversions "the hard way" was apparently quite a bit more common in India, where spares for, and knowledge of, the older model RE 500s is more readily available.

I find it pretty interesting to find the old threads, here on the forum, from the days when EFI first showed up in REs, and reading some of the passionate anti-EFI comments that some folks were making.

[Monkee]

I think that one would also be removing the fuel pump, and blanking off the large opening in the bottom of their fuel tank with cover that included mounting opening(s) for a petcock for gravity fuel feed.  This is not trivial, especially since Hitchcocks seems to no longer offer the carb. retrofit kit.  Perhaps the blanking plate component is still available, but I can't find it.  And of course, the 02 sensor, temperature sensor, and MAPS (if equipped), would also be vestigial, and could be removed and blanked.

IF I did it, I would do a carb conversion on my C5 the hard way, including replacing the ECU with an alternate ignition for several reasons;
  - I just wouldn't feel right about taping over the MIL light with a piece of electrical tape and ignoring the fact that the ECU was living in a constant state of alarm, having lost contact with many of its sensors.
  -  I suspect that old ECU costs more power consumption than the simpler TCI, especially if one is still heating their vestigial 02 sensor.
  -  The ECU is worth quite a bit more than the TCI, like $250 vs. $50.  If I pull out good parts and cash them in via Ebay, I calculated I would come out a couple hundred dollars on the plus side, even after purchasing the appropriate rotor, the TCI and the carb.  I get to sell the ECU, the fuel pump, the multi-lobed EFI rotor, the throttle body, the injector, and various sensors as spares, all of which are fairly high dollar items, and are, I believe, increasing in value year by year, as is generally always the case with discontinued models.

There is a thread from a few years ago, wherein a knowledgeable member listed all the RE P/Ns needed to do a 500 EFI export conversion "the hard way".  I participated in the thread, but I don't recall the thread title.  This would have been around 2021 or thereabouts.

The blanking plate is the most difficult piece of the puzzle, at this point.  I'm thinking the better solution might  be to modify an IB Bullet tank to mount on my C5, and then sell the EFI tank, which would be another net financial gain.

Most of our members seem to be well heeled westerners, who don't even consider something as pedestrian as saving a few dollars, or selling their unused parts for cash.  Apparently most folks who reported doing the conversion forked over the $400 or so that Hitchcocks was charging for their conversion kit, put their takeout parts into a box on a high shelf, and end of story.  Carb. conversions "the hard way" was apparently quite a bit more common in India, where spares for, and knowledge of, the older model RE 500s is more readily available.

I find it pretty interesting to find the old threads, here on the forum, from the days when EFI first showed up in REs, and reading some of the passionate anti-EFI comments that some folks were making.

I've managed to get a hold of all the parts needed for the "hard way " blanking plate included I have a buddy in India who can go to all the part stores as long as i provide him with a part number or at the very least a reference picture of the part I'm looking for. So im fortunate in that. I'm probably not going to sell the EFI parts just keep them for If and when i want to sell the bike and give the buyer the option of an EFI or Carbed bike.

I agree I'm not a fan of having an ECU where it pretty much all of its other functions aside from ignition timing and generating spark is pretty much blanked. I'd rather go the TCI and flywheel route. I'm not anti EFI by any means i've ridden plenty of well thought out EFI designed bikes where high precision is the name of the game in the engineering of the bike. Personally i think of the bullets and c5's as a hearty, robust, easy to work on machine that calls back to a time when motorcycles where made for people to upkeep themselves with a little elbow grease and know how. Not sure about where you guys are at in the world but around my parts if you're in the middle of a road trip and the fuel pump decides to quit, or the ECU throws an error because of some sensor not reading what its supposed to read, you're pretty much dead in the water and tow trucks or vans aren't common here. So I like the idea of carbs, gravity fed fuel system, and cables for the clutch and throttle none of that hydraulic clutch, ride by wire stuff.  (it has its time and place) Worst case is I bring a spare TCI, Coils, spark plugs, and petcock which wouldn't cost half as much as an ECU and all its related sensors and fuel pump.

At the end of the day its a personal thing I just feel more at ease that in a pinch I can cobble something together and get home.

Also as a sidenote my c5 doesnt have an o2 sensor i've looked high and low and there is none. no sidestand switch, no o2 sensor. From what I can see it only has a TPS, MAP, CHT , and a neutral switch. It really seems like they designed this bike to run on a carb and just slapped on some rudimentary EFI system to get it into the international market which i like. I've had many friends on their BMWs, Ducatis, FI harleys, etc have injector failures or fuel pump failures and ended up getting stuck in the middle of nowhere for 12 hours before help arrives.

[Monkee]

Forgive me, but I am not being rude. I just can't see what the point of all this is.

I can just about see why you might prefer a carb, but why go through all the pain of fitting a TCI when the existing ECU already makes perfectly good sparks?

Personally I wouldn't dream of changing a good EFI to a carb, because EFI works better. The fact that carbs cannot deliver sufficiently precise mixture control says it all.

No offense taken. Honestly the point is peace of mind for myself. I'm not chasing utmost performance or fuel milage, the EFI system works well enough as it is but i've just had too many personal experiences where EFI systems decide to take a shit at the worst possible time and no one but the dealership could sort them out. Or at least are authorized to do so. When i think of the bullets and classics I dont think high precision, cutting edge engineering, Performance, I think of a machine that isn't perfect but is robust and will take a licking and keep ticking. I try to avoid unnecessary complexity in operation where possible which in this case in my opinion is the EFI system. Its much simpler to trouble shoot a single carb, single cylinder motorcycle than one that has all these sensors albiet not very many sensors. On top of that access to parts to repair a carb or to get it tuned properly is so much more accessible at least for me. If i wanted to run pod filters, or a free flowing exhaust i wouldn't have to get a piggyback ECU or go to a dyno to get it to run relatively well.

thats just my two cents I'm in no way saying EFI in general is evil and that carbs are the only way a motorcycle should rely on for fuel delivery. Its just peace of mind on my end.

[SteveThackery]

I'm astonished by these stories of EFI failures. Are they actually real? Or are they stuff a mate said, or something you read on the Internet?

I've been riding for 50 years, and driving cars 48 years. I have literally never had a bike's electronics fail on me, and I've only had one electronic module fail in a car, and that was a good 35 years ago.*

They are extremely reliable, to the point where I don't worry in the slightest about them failing and leaving me stranded. If it happened, it would be pretty close to a once-in-a-lifetime event.

Oh, I've just remembered: a couple of years ago I had a reg-rec fail on a 40-year-old Yamaha - that had a carb, of course.

*I do appreciate that electronics were brought in part way through my 51 years.

[SteveThackery]

I think that one would also be removing the fuel pump, and blanking off the large opening in the bottom of their fuel tank with cover that included mounting opening(s) for a petcock for gravity fuel feed. 

Yes, of course - I forgot about that and realised it while lying in bed last night!

[Crabsapper]

Yes, of course - I forgot about that and realised it while lying in bed last night!

I had mentioned it.

[Adrian II]

This is not trivial, especially since Hitchcocks seems to no longer offer the carb. retrofit kit.

They still list them for for older AND post 2017 EFI models as well as the Himalayan. 2nd row onward, although a 289 Amal might look quite good on a UCE... Interestingly, the Himalayan kit appears to have TPS.

https://accessories.hitchcocksmotorcycles.com/s.nl?ext=F&sc=1&category=&search=carburettor%20conversion

It's worth noting the H's early EFI to carb conversions DID feature an AVL-type alternator rotor and TCI, which upped the cost. For the more recent kits they found a way to keep the stock ECU to run as a plain TCI with the EFI rotor, so certain functions CAN be bypassed/spoofed or whatever without crippling the whole thing, also making it easier to revert to EFI for next owner preference or having to get through certain mandatory technical inspections.

A.

[Monkee]

I'm astonished by these stories of EFI failures. Are they actually real? Or are they stuff a mate said, or something you read on the Internet?

I've been riding for 50 years, and driving cars 48 years. I have literally never had a bike's electronics fail on me, and I've only had one electronic module fail in a car, and that was a good 35 years ago.*

They are extremely reliable, to the point where I don't worry in the slightest about them failing and leaving me stranded. If it happened, it would be pretty close to a once-in-a-lifetime event.

Oh, I've just remembered: a couple of years ago I had a reg-rec fail on a 40-year-old Yamaha - that had a carb, of course.

*I do appreciate that electronics were brought in part way through my 51 years.

I was riding with 2 other guys about 500km climbing up to the city which was at around 5000' MSL and the ECU on my bike quit it was a Kawasaki W800. Just the other month my mate's BMW R90 had a injector + fuel pump failure in the middle of a closed off and remote expressway that was under development. I guess i'm just unlucky or we had lemon bikes. But i'd rather not have to have that in the back of my mind enjoying my trip.

[Monkee]

They still list them for for older AND post 2017 EFI models as well as the Himalayan. 2nd row onward, although a 289 Amal might look quite good on a UCE... Interestingly, the Himalayan kit appears to have TPS.

https://accessories.hitchcocksmotorcycles.com/s.nl?ext=F&sc=1&category=&search=carburettor%20conversion

It's worth noting the H's early EFI to carb conversions DID feature an AVL-type alternator rotor and TCI, which upped the cost. For the more recent kits they found a way to keep the stock ECU to run as a plain TCI with the EFI rotor, so certain functions CAN be bypassed/spoofed or whatever without crippling the whole thing, also making it easier to revert to EFI for next owner preference or having to get through certain mandatory technical inspections.

A.

I was heavily considering H's kit but the cost for for the kit to get shipped and taxes after the fact was a little too steep for me it was more affordable and accessible to get the conversion parts form india and some local RE distributors here. As for mandatory technical inspections those are non existent in my neck of the woods and are frankly a joke if they said there was any thing of the sort. I have a technically road legal 2 stroke with no lights and puffs more smoke than a stressed out chain smoker.

[axman88]

They still list them for for older AND post 2017 EFI models as well as the Himalayan. 2nd row onward, although a 289 Amal might look quite good on a UCE... Interestingly, the Himalayan kit appears to have TPS.

Thanks for posting that.  I couldn't find them, but I was spelling carburetor the american way, with just one "t".

I see there IS one that is probably suitable for my '12 USA export  C5 after all:   https://accessories.hitchcocksmotorcycles.com/accessory-shop/Mikuni-Conversion-Kit-EFI-Models/38127

And I see I can source the flange adapter separately:  https://accessories.hitchcocksmotorcycles.com/Amal-Carburettors/Flange-Adapter-Straight/12667
and the Adaptor Plate:   https://accessories.hitchcocksmotorcycles.com/21879

Wow!  Glad I was wrong about these machined parts being discontinued.

Not that I don't like EFI, but it is one of those things that is great when it works, especially in my opinion, for winter starting, but a real bummer when something fails.   The only failure I've experienced personally, was due to a loose battery connection and very easily rectified.

But, to Monkee's point, it seems like if a major EFI component like the throttle body failed, I might find myself India shipping time away from a replacement part.  That's something like 4 - 6 weeks, IF the part comes at all.  If I was far afield, that could be a very expensive situation in both time and money.  It's not like a Honda Shadow or an HD, where, in the USA, one is never further than two days express delivery from somebody who has the part.    I guess I could rely on Hitchcocks, they are reliable and just a few days away.  My impression is that RENA can't be relied on to have UCE parts in stock.

This is why I pretty much view my C5 as a vehicle suitable for local travel only, no further than the moto rescue van is willing to travel.  Converting to a carburetor does seem to my mind, to reduce the number of unknowns and make MacGyvered solutions much more viable.  Does this seem reasonable, or am I misinterpreting the situation?

[SteveThackery]

This is why I pretty much view my C5 as a vehicle suitable for local travel only, no further than the moto rescue van is willing to travel.  Converting to a carburetor does seem to my mind, to reduce the number of unknowns and make MacGyvered solutions much more viable.  Does this seem reasonable, or am I misinterpreting the situation?

No, I think your conclusion is reasonable. Although I think modern electronics are very reliable, I also think that they are effectively irreparable when they do fail. In terms of sustainability, the carburettor is surely the way to go.

Now, about electronic ignition. Are you certain that you can find a system that's as reliable, or more so, than the original ECU? If reliability and repairability are of primary concern, you should probably revert to points-based ignition.

Realistically that wouldn't be practical, so you will need to carry a spare pickup and ignition module with you if you want the ability to repair by the roadside.  Are you willing to do that?

[Monkee]

No, I think your conclusion is reasonable. Although I think modern electronics are very reliable, I also think that they are effectively irreparable when they do fail. In terms of sustainability, the carburettor is surely the way to go.

Now, about electronic ignition. Are you certain that you can find a system that's as reliable, or more so, than the original ECU? If reliability and repairability are of primary concern, you should probably revert to points-based ignition.

Realistically that wouldn't be practical, so you will need to carry a spare pickup and ignition module with you if you want the ability to repair by the roadside.  Are you willing to do that?

Honestly if its at all possible I probably would. One of the reasons why i was thinking of getting a cone evo harley. I dont think there is a way to use condenser and points on the new UCE engines? if there are i'd like to know

[Adrian II]

I suppose you could come up with a clever mounting for a contact breaker assembly triggered by some sort of cam effort on the outer face of the rotor. Needs to be shaped so as to open the heel of the contact breaker fairly gently. Someone might already have done this, but I've never seen a report of it.

The AVL flywheel has a magnetic strip on it for the TCI trigger, I suppose you could do something with that.

You other option is to get an older style Bullet which already has points ignition.

A.

[axman88]

No, I think your conclusion is reasonable. Although I think modern electronics are very reliable, I also think that they are effectively irreparable when they do fail. In terms of sustainability, the carburettor is surely the way to go.

Now, about electronic ignition. Are you certain that you can find a system that's as reliable, or more so, than the original ECU? If reliability and repairability are of primary concern, you should probably revert to points-based ignition.

Realistically that wouldn't be practical, so you will need to carry a spare pickup and ignition module with you if you want the ability to repair by the roadside.  Are you willing to do that?

I don't see why carrying a spare ignition module would be objectionable.  It's small and inexpensive.  I'm not sure this is the correct one, but I would probably purchase a spare, right up front if I was making the conversion.  https://www.ebay.com/itm/195799258167

The pickup coil seems like there is little to go wrong, and might even be repairable with a bit of patience.  But again, small and cheap, so why not keep a spare?:  https://www.ebay.com/itm/295139818166

But, I don't think it would be necessary to carry.  It seems to me that an ignitor that would work adequately, although it might not be identical and would require hacking the wiring, could be pretty easily found in any number of motos from the 70s onward.  And there are all sorts of options on Amazon, just a day or two away.  Perhaps this one, from a Suzuki single, would be quite adequate to make sparks:   https://www.amazon.com/Amhousejoy-Motorcycle-Ignitor-Digital-Ignition/dp/B08B4S913J/ref=sr_1_2 

And my thought for self support while on tour, was not that I would carry everything I might possibly need, but rather that I would HAVE everything that MIGHT be needed, nicely organized, and if I ran into trouble, I'd call my friend back in Chicago, and have them overnight express me "box C-12", which I knew contained the part I had forseen might fail.  This same technique could certainly be applied to the original EFI system, but the cost of this advance planning becomes quite a bit higher, due to the longer list of more expensive components.

Sallying forth, without all this planning and relying on the basic reliability of the parts is probably fine.  Certainly people do it.  To Steve's point, these electronic components are very reliable.  On an HD, a Honda or a Yamaha cruiser, that sold well in this country, I wouldn't think twice about taking my chances, relying on the fact that spare parts were probably not going to be hard to find, if I had the very bad luck to experience a failure.  But, with the RE single, relatively rare in the USA, I would be surprised if a replacement for certain parts was NOT an issue.  I suspect that this isn't the case at all for the 650 twins, the 350s, and the Himalayans, but these are all in current production and mainstream distribution.

What we do, when we change from EFI to carburetor, the hard way, is to go from an electrical system that has 8 or 9 points of potential failure, (and substantially more if we count the wiring and connectors)
ECU
Fuel Pump
TPS
Pickup coil
MAPS (if equipped)
Temperature sensor
Lambda (02) sensor
Injector
Ignition Coil

To a system that has three.  This seems inherently more reliable.  I wouldn't be surprised if the most failure prone element of the electrical systems, are the connectors.  Less is better.
TCI
Pickup coil
Ignition Coil

I think it's valid to say that we will have given up some potential electrical failures for more potential mechanical failures in the carburetor, but the high pressure fuel system and its required regulator are unique to the EFI system.  In my opinion, mechanical failures are much more common than electronic, but are easier to fix. 

Declaring either as "more reliable" overall would be a complicated analysis.  I'd be going more for "more REPAIRABLE, with only parts from Walmart and working under a tree on a piece of cardboard", which is what I believe the mostly Indian proponents of "never EFI!" were also going for.  It took over a decade, and several emissions regulations updates, but that argument seems to have subsided.

Still, it does seem a little odd that carburetors on motorcycles may have survived longer in the new world, than in the old.
https://yamahamotorsports.com/models.php?product=259&action=features

[SteveThackery]

Still, it does seem a little odd that carburetors on motorcycles may have survived longer in the new world, than in the old.
https://yamahamotorsports.com/models.php?product=259&action=features

Perhaps I've misunderstood your point here, but I'll say it anyway...

Carburettors cannot meet European or American emission regulations, which is why every bike sold here has fuel injection (I seem to think bikes below 125cc are treated differently in the EU?).

Where emission regs are sufficiently lax, carbs can continue to be used. I think a carb plus a basic TCI will be cheaper than fuel injection.  I'm guessing bikes for the Indian market can still use carbs?

[SteveThackery]

I don't see why carrying a spare ignition module would be objectionable. 

No, me neither. I was just saying that if you distrust electronics for the very good reason that they are not repairable, then logically that should apply to the electronic ignition system as well. Hence pointing out you would need to carry a spare if you are hoping for a roadside repair.

Personally I'm happy to trust the electronics as they are. Perhaps I like to live dangerously, or perhaps my riding circumstances are much more benign. I suspect the latter. 

[Monkee]

I don't see why carrying a spare ignition module would be objectionable.  It's small and inexpensive.  I'm not sure this is the correct one, but I would probably purchase a spare, right up front if I was making the conversion.  https://www.ebay.com/itm/195799258167

The pickup coil seems like there is little to go wrong, and might even be repairable with a bit of patience.  But again, small and cheap, so why not keep a spare?:  https://www.ebay.com/itm/295139818166

But, I don't think it would be necessary to carry.  It seems to me that an ignitor that would work adequately, although it might not be identical and would require hacking the wiring, could be pretty easily found in any number of motos from the 70s onward.  And there are all sorts of options on Amazon, just a day or two away.  Perhaps this one, from a Suzuki single, would be quite adequate to make sparks:   https://www.amazon.com/Amhousejoy-Motorcycle-Ignitor-Digital-Ignition/dp/B08B4S913J/ref=sr_1_2 

And my thought for self support while on tour, was not that I would carry everything I might possibly need, but rather that I would HAVE everything that MIGHT be needed, nicely organized, and if I ran into trouble, I'd call my friend back in Chicago, and have them overnight express me "box C-12", which I knew contained the part I had forseen might fail.  This same technique could certainly be applied to the original EFI system, but the cost of this advance planning becomes quite a bit higher, due to the longer list of more expensive components.

Sallying forth, without all this planning and relying on the basic reliability of the parts is probably fine.  Certainly people do it.  To Steve's point, these electronic components are very reliable.  On an HD, a Honda or a Yamaha cruiser, that sold well in this country, I wouldn't think twice about taking my chances, relying on the fact that spare parts were probably not going to be hard to find, if I had the very bad luck to experience a failure.  But, with the RE single, relatively rare in the USA, I would be surprised if a replacement for certain parts was NOT an issue.  I suspect that this isn't the case at all for the 650 twins, the 350s, and the Himalayans, but these are all in current production and mainstream distribution.

What we do, when we change from EFI to carburetor, the hard way, is to go from an electrical system that has 8 or 9 points of potential failure, (and substantially more if we count the wiring and connectors)
ECU
Fuel Pump
TPS
Pickup coil
MAPS (if equipped)
Temperature sensor
Lambda (02) sensor
Injector
Ignition Coil

To a system that has three.  This seems inherently more reliable.  I wouldn't be surprised if the most failure prone element of the electrical systems, are the connectors.  Less is better.
TCI
Pickup coil
Ignition Coil

I think it's valid to say that we will have given up some potential electrical failures for more potential mechanical failures in the carburetor, but the high pressure fuel system and its required regulator are unique to the EFI system.  In my opinion, mechanical failures are much more common than electronic, but are easier to fix. 

Declaring either as "more reliable" overall would be a complicated analysis.  I'd be going more for "more REPAIRABLE, with only parts from Walmart and working under a tree on a piece of cardboard", which is what I believe the mostly Indian proponents of "never EFI!" were also going for.  It took over a decade, and several emissions regulations updates, but that argument seems to have subsided.

Still, it does seem a little odd that carburetors on motorcycles may have survived longer in the new world, than in the old.
https://yamahamotorsports.com/models.php?product=259&action=features

I whole heartedly agree with this sentiment. for me personally its not which is more reliable/better its whats easier to repair. IF i was going for a long enough ride and remote enough like i did a couple years back i definately would carry spares. Its never fun to push a bike up a hill for 5km.

[axman88]

Perhaps I've misunderstood your point here, but I'll say it anyway...

Carburettors cannot meet European or American emission regulations, which is why every bike sold here has fuel injection (I seem to think bikes below 125cc are treated differently in the EU?).

Where emission regs are sufficiently lax, carbs can continue to be used. I think a carb plus a basic TCI will be cheaper than fuel injection.  I'm guessing bikes for the Indian market can still use carbs?

I don't know WHY you say that.  There's no evidence that USA emissions standards are anywhere near as restrictive as Euro or Bharat Stage standards.

As you can see from that link I posted, Yamaha is still offering the carbureted XV250 in the USA market.  I'm quite sure I can find other examples of road bikes sold here that are carbureted.  The only reason that there are not MORE machines with carburetors, in my opinion, is because the USA is a small and shrinking market, and manufacturers choose to standardize their production to meet the demands of the largest markets.

As you can see HERE, the USA emissions standards haven't been changed since 2010:
https://www.transportpolicy.net/standard/us-motorcycles-emissions/

These standards have applied in the USA for the last 14 years:   HC+NOx   0.8 (g/km)    CO    12.0 (g/km)     NOx   n/a

These standards appear to me to be quite a bit LESS RESTRICTIVE than Euro 3 standards.  Which I find here:
  https://www.bikesure.co.uk/bikesureblog/2023/11/ulez-motorcycle-guide/#:~:text=Since%20then%2C%20the%20standards%20have,nitrogen%20oxide%20limit%20for%20diesel.

 HC+NOx   0.20  (g/km)    CO    2.3 (g/km)     NOx   0.15 (g/km)

Of course, by now, Europe is on Euro 5 standards for motos, and India skipped 5 and went straight to BS 6.  So, actually, you have it exactly backwards and India has the most restrictive standard for motos at this time.

[SteveThackery]

I'm happy to be corrected - thank you. 

My point remains: carburettors won't meet current emission regs (certainly here in Europe), which is why fuel injection is used nowadays.

I assumed the USA had similar standards to the EU, mostly because California led the way in emissions reduction, but if you say the standards are that much lower for bikes in the USA I stand corrected.

However, the fundamental principle remains: if carburettors are fitted then the emission regs must be lower than those in Europe.