[sagefilio]

Hello!

It's been a long time since I've posted here, but since I've definitely relied on this forum in the past I figured I'd contribute to it. I also noticed someone asked about carbs on these bikes and that thread devolved a bit, so I figured I'd give this step by step documentation a go.

Some background: I purchased this bike new in 2013. Followed the break in, then took in on a 3000 mile trip (skyline drive/blue ridge parkway, if you have a chance do it). Bike was stock and ran very rich during that trip. I added a K&N filter, D&D exhaust and a PC mapped for those things. Bike still ran incredibly rich, to the point of fouling plugs. I started messing with the tune, and adding an autotuner/wide band o2 sensor to see what was going on. I've been messing with tuning this bike now for 3 years and not getting anywhere. I've read blog posts, bought a book on it even and couldn't get very far without a dynometer. The closest dynotuner that will take non harley's is 100 miles away. So for the cost of a dynotune 100 miles away (+renting a method of getting the bike there) I just purchased the Mikuni Carb kit from Hitchcocks. Something I can much more easily tune to this motorcycle and have experience doing.

Photo of the kit is attached here. It does seem a few things have changed from the photo on Hitchcock's website. The petcock is noticeably different, with a 2 piece nozzle and copper/rubber crush washer included. I've attached a photo of it mounted to the tank. As usual, the machined aluminum parts hitchcocks produces for these (the gas tank cap and manifold) look and feel superb.

The only other thing I'll say so far is the air filter is almost too small for the carb. It took about 20 minutes of cajoling to get it onto the carb. Basically loosening the rubber, and shaving a small bit off of it with the sharp ends of the inlet.

For those wondering it's a Mikuni VM32 with a 185 main and 25 pilot. They supply a size up and down of each for fine tuning.

I'm going to wait till tomorrow to mount and test the stock jetting, and will provide another update with photos then. Also if you're in the market for a perfectly fine fuel pump, injector, K&N filter, Power Commander or autotuner let me know, I'm going to be selling all of it!

[Snotball]

I will be interested to hear how you go with this. I have the carb kit from Hitchcock’s for my 2019 C5 but haven’t fitted it as yet. Did you need to change the stator or pickup? I believe this was necessary with some of the earlier bikes.

[gizzo]

I will be interested to hear how you go with this.

Same. I'm not planning a swap but it's good to see other people's projects.

[suitcasejefferson]

Replacing the EFI on a UCE bike with a carburetor is by far the best modification you can make. I bought my 2013 B5 Bullet brand new with the intention of doing the carburetor. I would not have otherwise bought an EFI bike.

I had a few problems, but it is difficult to remember the exact details, since it has been 8 years since I did it. And the kit may have changed. Mine came with an Amal carburetor, which I absolutely love. It is as simple as a carburetor can get. And it has a tickler on it just like they used to.

I had a problem getting the throttle cable to fit/work properly. After a lot of fiddling, I resolved that problem by using parts from a big box of spare motorcycle parts I have been collecting for decades.

I was unable to make the choke cable/linkage work, and gave up on it. Since the Amal carburetor that came with the kit had a tickler, I did not need the choke to get it started and I never ride a bike until it is thoroughly warmed up.

The last problem confused me at first. The bike would idle fine, but would cut out when I tried to ride it on the street. I finally decided that the carburetor was not getting enough fuel. I removed the petcock and temporarily connected a larger fitting and fuel line directly from the tank block off plate to the carburetor. The bike ran fine. So again using my box of leftover spare parts and a couple of plumbing parts from Home Depot, I fabricated a fuel line with an inline petcock. I could not find a petcock that would fit the threads in the fuel pump block off plate. That could probably have been done by drilling out and rethreading the hole in the block off plate, but the way I did it worked just fine, and has been on the bike for over 14K miles now without any problems.

Unfortunately the kit I used required retaining the throttle body (wrapped up and stuck in an out of the way place) so that the ECU would still control the ignition. That does eliminate having to pull the flywheel and replace ignition parts, but I would have MUCH preferred to get rid of the ECU and just use a standard CDI ignition, even if it meant more money and more work. But at least I was able to get rid of the failure prone (and VERY expensive)  electric fuel pump and the very poorly designed air filter that leaked all the way around the edges, allowing dirt into the engine.

The bike runs so much better than it did with the EFI that it's hard to find words to describe it. It pulls hard from idle to full throttle, with no more wheezing and hesitation. It has a much richer, fuller sound. Yes, I also have an aftermarket exhaust, but I did the carb conversion first. It made a difference. The aftermarket exhaust just made it that much better. I was amazed that the carburetor was jetted perfectly for both the exhaust and the cone type filter. It no longer runs lean like it did. I can also adjust the idle down to get the proper thump thump thump sound out of it. I love getting gas on my finger when I tickle the carburetor, just like my former (and greatly missed) 1966 Bonneville.

Yes I had to deal with a few problems when installing the conversion. But I have absolutely no complaints about the way it starts and runs. I can't think of any way it could possibly be any better, other than being able to get rid of the ECU.

[viczena]

Swapping a ECU against a carb is by far the most dumb modification you can make. It does not convert your bike into an oldtimer. Or into something special or precious. Just into an unreliable bike. That nobody wants to buy, if you ever want to sell it.

see for example https://forum.classicmotorworks.com/index.php?topic=30527.0;topicseen

If you want a carburated bike, buy one. They are cheap. Sometimes cheaper than the EFI-Carb conversion.

[AzCal Retred]

I KNEW you couldn't keep your oar out of the water here! 
Does this mean you are willing to personally drive over to their homes & sort out these machines EFI's, on your own time, on your own dime?
What's dumb is worrying about what other folks spend their recreational dollars on. They had an issue, they found a solution they liked. End of game.
You do you, let the folks that bought their own hardware with their own money do as they will with their own stuff.
Do you need the rest of us to give you a list of the machines you should own and the modifications you should (or shouldn't) make? I know you'd love it.
 

[viczena]

You can make dumb decision as long as you want. They remain dumb decisions.

[Bilgemaster]

From his own Forum and postings here it's abundantly clear that 'Viczena' clearly understands  all of the arcane workings of those electronic fripperies in a way I never shall. When considering any prospective "new" ride I am always happy to learn it is carbureted, and if I owned a UCE Bullet or Conti and its EFI or related systems gave me the least concern, I would be another prime candidate for a Hitchcocks carb conversion, likely preferring an Amal Concentric setup since I've had several, and could likely break down and reassemble them blindfolded, like in Army bootcamp. I'll concede that I'm a bit of a Luddite where all this is concerned. But gravity always works, and it seems that 90% or more of the woes that afflict UCEs have to do with some electro-farkle or other acting up such as fuel pumps or ECUs or the host of other sensors or gimcracks utterly lacking in my "primitivo" Iron Barrel. I lack 'Viczena's' obvious divinitory talents for interpreting ohmages and Amperes, and frankly just don't care to learn them. If I can't fix it with some spray carb cleaner and an air hose, I'm just not interested. On the flip side of the coin, I do recall an earlier thread posted here by someone who'd wanted to "upgrade" their carb to EFI--either an Iron Barrel or an AVL, I seem to recall...though it might have been a Himi or even a home market UCE, both of which came in both EFI and Carby flavors yonder and in some non-US export versions. At the time I'd thought, "Why the hell would anyone want  to do that?" I mean, why would you want to replace a perfectly adequate fueling system that one can replace for like $24 brand new with one so prone to gremlins, where, if the least little hiccup occurred, you'd be looking at maybe a couple hundred bucks worth of prospective fixes? For a pony or three more at the throttle? Not for me, thanks.

So, I well respect anyone's choice to fuel their ride any way that works for them. I also doubt a well done carb conversion would harm resale value, at least here in the States. If anything, it might increase it as a "reliability enhancement". Of course, in Germany, with those white lab-coated TüV (vehicle inspection) guys peering into your ride's  every nook and cranny seeking those Unzugelassenheiten ("unapprovables"), your mileage (or "kilometerage"?) may vary. I doubt many American cars, even some fresh off the lot, would squeak through a German vehicle inspection. So, that's the demanding current in which our man 'Viczena' is swimming.

[viczena]

You are right. It does not make real sense to upgrade from Carb to EFi. Better you buy a new bike. There are some minor exceptions for very special occasions. For example if you have a car engine built into your bike, for which EFi conversions are readiliy available and profoundly tested.

Most EFi problems with Royal enfield bikes are related to contaminated/rusty fuel. Easy fix would be a secondary fuel filter around the fuel pump. And maybe seal the inside of the tank.

[Richard230]

My son-in-law bought a well used 1988 Honda CRX for too much money, then removed the engine, bought a new engine and rebuilt it, installed the rebuilt engine, replaced all of the suspension components, brakes. tires, seats and is currently replacing the car's automatic transmission with a well-used 5-speed manual transmission. He likely has sunk close to $10K into that car so far and has only driven it a few hundred miles since he bought it. I have ridden in the car and it rides like a rattle trap, compared with my 1998 rattle trap Saturn.   He is constantly fixing oil leaks and making minor repairs and adjustments. (BTW the car has no ABS. But it still comes to a stop - eventually.  )  What a waste of time and money. But it is his time and his money and he apparently has a hobby that he loves that mostly keeps him out of trouble, so there is that. 

[Bilgemaster]

My son-in-law bought a well used 1988 Honda CRX for too much money, then removed the engine, bought a new engine and rebuilt it, installed the rebuilt engine, replaced all of the suspension components, brakes. tires, seats and is currently replacing the car's automatic transmission with a well-used 5-speed manual transmission. He likely has sunk close to $10K into that car so far and has only driven it a few hundred miles since he bought it. I have ridden in the car and it rides like a rattle trap, compared with my 1998 rattle trap Saturn.   He is constantly fixing oil leaks and making minor repairs and adjustments. (BTW the car has no ABS. But it still comes to a stop - eventually.  )  What a waste of time and money. But it is his time and his money and he apparently has a hobby that he loves that mostly keeps him out of trouble, so there is that. 

Not exactly my cup of tea--I'd rather resurrect a '37 Hupmobile Iron Cloud Deluxe or something, but to his credit, the '88 CRX si100 did make the cut for a series of articles titled, "100 Cars That Matter" at: https://www.motorauthority.com/news/1123551_1988-honda-crx-si-100-cars-that-matter.

I recall my buddy always wanted a CRX, but he wasn't exactly the wrenching sort. In fact, when he moved into his new place he let me have my pick of all of the previous owner's tools and other workshop and some boating gear. Personally, I always held a furtive admiration for those little  '70s Civics like this one, instinctively knowing it might attract a more folklorically costumed class of panhandlers. No rank squeegee-wielders here...

"Ask her if she wants me to buff
her grill with my Lederhosen"

[Richard230]

When I was stationed in Panama during the mid-1960's I saw a couple of Honda S-800 cars, both the convertible and the fastback coupe. Fast little buggers. I think they had chain drive to the rear wheels. They looked a lot like little MGB British sports cars. I don't think they were ever sold in the U.S., though. 

[sagefilio]

Hello!

An update; the carb is installed! Lets break this down a bit. First, when removing the EFI you have to unplug a lot of stuff. According to Hitchcocks, for my model year (2013) all but one of these plugs are left unplugged. There is one they provide a resistor plug for. The others can be tucked away. The only downside is the MIL lamp will always be on, but this can be easily bypassed with their supplied directions. Here are some photos of the plugs for your edification:





Next up, the stock airbox is plugged with a supplied plug. Very handy, but there is still the ductwork for cold air. I plan on removing and plugging that up somehow. Any suggestions hive mind?


Now a couple of notes on fitment. Fitting the carb outlet into the rubber boot took me a solid 30 minutes of wrangling. It's not easy, and maybe I'm dumb and there's a trick to it, but I ended up using a vice to hold the carb while using a screwdriver to pop the rubber onto it. Really was a pain. I'll also mention that the throttle cable is almost too short. I'm going to try rerouting it one more time, but as it stands at full right lock it accelerates the bike.

Some other tips! When attaching the cable to the carb start with this end first:


Then connect your cable to the throttle using this hole. It's the only option where I was able to have a complete actuation of the slide, and hitchcocks doesn't specify:


Lastly, I also think the fuel line they provide is too short for the new petcock, I'll ask for another or just make another, haven't quite decided. It works in a pinch, but I could see that line pinching after a while pretty easy:


Finally, it's all installed! Next post will be about tuning. I've given it a ride around the block and off the bat the throttle needs adjusted a bit as well as idle. I don't like the throttle accellerating at full lock, hopefully I can reroute and give myself a little more slack. So far though it's snappy & responsive with no power loss or gain that I can tell off the bat.

[sagefilio]

I will be interested to hear how you go with this. I have the carb kit from Hitchcock’s for my 2019 C5 but haven’t fitted it as yet. Did you need to change the stator or pickup? I believe this was necessary with some of the earlier bikes.

This kit doesn't require any work to be done to the stator or pickup. It's my understanding that for my model year the ECU only uses engine speed data to set timing. I need to verify that, but so far I haven't noticed any timing issues on my ride around the block. I'll keep an eye on it though. The TPS plug is left unplugged in this kit.

[Haggis]

I used a rubber cover from the back of a car headlight unit.
They come in loads of different diameters to fit.