[Snotball]

I have a C5 Euro IV. I it has a small catalytic converter in the standard header pipe and a larger one in the standard muffler. After some research I purchased a performance header pipe and muffler from Hitchcocks which is advertised as Euro IV compatible for my bike.

The new header pipe is single skinned unlike the original which means it can pass a lot more gas than the double skinned standard header. The new muffler is basically straight through.

Complete waste of money. The whole thing is much louder but there is zero increase in performance in the low to mid range with a small increase at the top end if you want to wring it’s neck. These bikes are not about having their necks wrung.

The only combination that came close to running properly was the Hitchcocks header pipe combined with the original muffler. But this was still not as good as the original, standard setup.

The header pipe went straw coloured for its whole length and dark blue for about half its length within a very short time. This indicated to me that it is running very lean and that the ecu is unable to compensate. Perhaps the ecu is tuned exactly for the standard intake/exhaust setup with only enough variability to cater for the small differences between individual bikes.

Put it all back to standard and everything is running as it should. I actually think slightly better in the mid range as it now zips up hills easily at 60MPH without having to continually screw on the throttle as was the case with the Hitchcocks setup.

I would be keen to find out what others with a C5 Euro IV have found?

[swamp2]

You've made modifications far beyond what the stock ECU is designed/able to compensate for.  If you want to make that work, look at a Power Commander or Powertronic unit to get it under control. 

[Snotball]

You've made modifications far beyond what the stock ECU is designed/able to compensate for.  If you want to make that work, look at a Power Commander or Powertronic unit to get it under control.

Yes it’s a shame Hitchcocks advertises this system as being suitable for the Euro IV ECU as in fact it isn’t without adding a Power Commander or similar. Live And learn. The parts won’t be wasted however as I plan to replace the FI with a Mikuni carb at some point in time. Already have the carb and now working out the sensors that need to be kept/bypassed/removed

[Haggis]

May be you have other problems with your particular bike? Most are very pleased after a pipe and can change on the euro4  because the ecu can cope with the change better than the euro3.

[Farmer_John]

My question is really what did you expect?  The brain box is programmed for the standard inhale and exhale. So by replacing the exhaust, you’ve now got an engine that acts like we do with a head cold. You can blow like the dickens out through your mouth, but your nose is struggling to fill your lungs.

If you ordered the polished stainless header, it’s SUPPOSED to turn straw color. That’s the nature of stainless steel.

Good luck, but do ask questions here. There are many knowledgeable people on this forum that can and will help.

[JVS]

The Hitchcocks single walled pipe will turn blue / brown on the first start within 5 mins of use. Even if your mixture was close to optimum, it would still turn blue up to the first bend just after the cylinder head (just because it's thin).

I believe the only sensible thing without installing a PCV or carb is to keep the stock header and install the Hitchcocks silencer. Any more de-restriction of the exhaust system did make it quite lean (talking about Euro 3).

[ace.cafe]

Larger diameter exhaust pipe always sacrifices lower rpm performance in favor of maybe an increase in upper rpm performance. That is standard exhaust tuning practice.

Free flowing the exhaust always leans out the mixture in the cylinder due to reduced egr gases buffering the mixture in the cylinder. Again, standard exhaust tuning practice.

The bottom line is it did exactly what would be expected, but the vendor apparently didn't mention that, and you seemingly didn't know it either. There should be better communication.

[Snotball]

Swamp 2, Farmer John, JVS and Ace,

Good comments. All true

[gashousegorilla]

   Going from that stock 1 1/8 " ID head pipe to the 1 1/2" ID HC pipe ... WITH THE CORRECT AIR FUEL adjustment !!..... he should see a big improvement in mid range and top end.    He leaned the crap out of it !   Of course it runs like shyte now.         That power would come on a lot earlier in the rpm range if his air fuel ratio was not so lean.      He almost HAS to ring it's neck  now to get any power out of it.   And if he were to keep doing so , he might just cremate an exhaust valve.     Ahhh... stick with a puny head pipe if you never want to get on a highway and want to struggle to hit  an actual  68 mph. And if you just want it to feel  zippy for the first ten feet.   Otherwise , if you want these bikes to be more ALL around capable put a bigger head pipe on... and tune for it.   ANY change to the intake or exhaust will effect the fueling to a greater or lesser extent on these bikes, or any bike for that matter .   EFI or Carb.   Going from  a 1 1/8" to 1 1/2 "   is a big change !    I DO agree.... every aftermarket seller should advise people of this .

[Snotball]

   Going from that stock 1 1/8 " ID head pipe to the 1 1/2" ID HC pipe ... WITH THE CORRECT AIR FUEL adjustment !!..... he should see a big improvement in mid range and top end.    He leaned the crap out of it !   Of course it runs like shyte now.         That power would come on a lot earlier in the rpm range if his air fuel ratio was not so lean.      He almost HAS to ring it's neck  now to get any power out of it.   And if he were to keep doing so , he might just cremate an exhaust valve.     Ahhh... stick with a puny head pipe if you never want to get on a highway and want to struggle to hit  an actual  68 mph. And if you just want it to feel  zippy for the first ten feet.   Otherwise , if you want these bikes to be more ALL around capable put a bigger head pipe on... and tune for it.   ANY change to the intake or exhaust will effect the fueling to a greater or lesser extent on these bikes, or any bike for that matter .   EFI or Carb.   Going from  a 1 1/8" to 1 1/2 "   is a big change !    I DO agree.... every aftermarket seller should advise people of this .

Thanks gashouse gorilla. The more opinions and comments the better. Only way to make an informed decision is to get all the facts!

[kdxandrew]

I'd do the carb conversion - then its easier to tune.
When I put open header and tail pipe on my 350 I had to go from 110 to 125 main and 12.5 to 17.5 pilot - that's a fair bit more fuel.
Funny thing is the fuel economy actually went UP from around 28 km/l to about 38

[9fingers]

A carb is easier to tune only if you are uncomfortable using a PC (like me) with the PC V, but GHG did it for me and I would NEVER go to a carb after having it properly tuned with EFI. But the EJK is easy to use and inexpensive. But if you know how to fiddle with needle, pilot and main jet and don't mind removing the carb a half dozen times, then go for it. Not everyone has a GHG nearby...........I am a lucky guy! Changing the header and silencer saves something like 13lbs and allows a free breathing engine, more midrange and top end power and was well worth it in my book. I did try a few different tail sections and settled on one from Inida that had good performance, looks and great sound. The Goldstar item from Hitchcocks had the best power but was too loud for me.
9fingers

[kdxandrew]

Don't need to take the carb out to change jets by the way - can drain and take the float bowl cover off in situ (I found this out after about 20 iterations of jet changes!)

[suitcasejefferson]

I don't really understand why anyone would be looking for more power from a RE single. But that also applies to Harleys. To me it's all about the feel and sound. I replaced the muffler (just the muffler, not the header pipe) with a much smaller, shorter, and 20 pound lighter one than stock. I also replaced the EFI CRAP with an Amal carb using a kit from Hitchcock's. I don't have any tolerance for emissions crap or electronics on a motorcycle. Overall power did not increase that I can tell, but throttle response is 10 times better. No more sputtering and wheezing. The carb fattened up the mixture nicely, and it now pulls strong, and the sound is much deeper. Part of that may be the exhaust, but because I replaced the exhaust first, I can tell that most of it came from the carb. An EJK for the EFI might also make things better, but I am not spending a penny on electronics for a motorcycle.

[gizzo]

Fair enough and to each their own. I'm in a boat floating down the same stream as you in as much as I'm not super interested in going for massive power from my Enfield. It's a lot cheaper and easier to jump on something that's already faster. OTOH I'm not adverse to inexpensive mods that give a bit more performance or a nicer riding experience. I'll be replacing my header some time. Not because I'm expecting a remarkable  power boost, just that my stock chrome one looks like arse with all the rust, and the stainless one looks cool.  I like the easy starting at the push of a button EFI. And the Powercommander and autotune module make tuning easy.

If I want to make my life hard, I go fool around with the FCR on my supermoto.

[ace.cafe]

After riding on a GT 535 with 38 rear wheel hp, you might like it.

It is basically a 21st century BSA Gold Star DBD34, and probably a bit faster than one too. A true vintage style sporting single in every sense of the term, but with EFI and disc brakes.

[gizzo]

After riding on a GT 535 with 38 rear wheel hp, you might like it.

I really would, you know it. And if I had enough money there'd be no reason to not go mad on it. But I just can't justify the expense. You know how it is.

Tom, when do we get to see some footage of the Ace Head CGT vs a stock one at the track?

[ace.cafe]

I really would, you know it. And if I had enough money there'd be no reason to not go mad on it. But I just can't justify the expense. You know how it is.

Tom, when do we get to see some footage of the Ace Head CGT vs a stock one at the track?

I guess it will be up to Guaire(Bill).

There are only 3 units currently existing. Matt still has his Gen 1 version, but I don"t know if he plans on track days. Otto has given some very good data and footage of his Gen 2 version, but he sort of faded away from the forum. Bill is just getting his Gen 3 version finished up now.

It basically falls on the owners to do those sorts of things. My GT 535 was stolen, so I don't even have one anymore.

Our head-to-head racing experience has been with the Iron Barrel Fireball 535 which had similar hp and weight.
If you watch our first video of Chumma's Fireball vs ChuckD's pre-Fireball Bullet(with free-flow mods and VM34, you can see that it is not even a contest. It was our first video 9 years ago.
https://youtu.be/D8A5it-R9rA

Chuck's Bullet had about maybe 20 rwhp at that point. Very similar to a GT 535 would have. It was running against the very earliest Fireball before we did any dyno tuning, and probably had maybe 30 rwhp estimated.
After some further development and some dyno work, Chumma took his Fireball over to a friend's shop that specialized in BSA DBD34 work. He drag raced against a DBD34 on the road in front of the shop, and beat the DBD34.
The best Fireball 535 Iron Barrel models peaked at about 36 rwhp @6000 rpm.

Otto dyno'd his UCE Continental GT 535 with ACE head and cams, with squish mod on Wossner piston and 36mm bored throttle body and ACE airbox mod with velocity stack, at 37.9 rwhp @6500 rpm. Essentially 38 in round numbers. It recorded 111 mph on a GPS Speedo on the street .

I think the GT with ACE head has more potential to be released with more rpm, If we could get past the rev limiter being only able to increase revs to 6500 max rpm.

As a reference, Bullet Whisperer's 500 Bullet vintage road racer was getting around 45 rwhp @7300 rpm on his dyno on methanol with 13:1 compression and full-race everything. It is the 2nd fastest Bullet on the track, behind Linsdell. We got him about 10% more hp with our head work that we did for him, but it still isn't as fast as Linsdell's. But he beats Manxes and G50s every race weekend, so it's a very fast machine.

For a street legal 535 single road bike with tractable road manners on pump petrol and excellent reliability, I think the GT 535 with ACE parts is an extremely formidable bit of kit. Unfortunately, we are slowed down a lot now, after all the earlier production delays, and the price is still high, so the prospect of future owners for this kit is very much in question right now.

[kdxandrew]

For me, its not really a search for power as such - just letting it breathe as it should instead of being strangled.  The 350 was VERY flat stock, but now runs like you would expect a 350 should.
No point in going for much extra power on these bullets anyway, 'cause after 120 kph an inherent speed wobble starts to be felt, which by 130 is getting really quite alarming!

[suitcasejefferson]

Unfortunately I cannot ride the GT because the riding position is a bit too extreme. And for some reason even the first generation GT535 could not be converted to a car. I just have no interest in EFI.

A larger diameter exhaust will definitely move the powerband up in the RPM range, unless the exhaust port and valves themselves create a bottleneck. One neat thing about carburetors, and what made mine run so much better after replacing the EFI with a carburetor, is that a smaller carburetor will move the power down in the RPM range. I don't know what the diameter of the Amal carb I installed is, or for that matter what the diameter of the stock throttle body was. But from the feel, I'd be willing to bet the carburetor has a smaller internal diameter. An electronic tuner can change the mixture, but the throttle body remains the same size. Bore and stroke also have a lot to do with it. I have always loved long stroke engines. I love the feel, sound, and low end power they produce. In the case of the Royal Enfield single however, it makes the bike unsuitable for riding at higher speeds. Long stroke singles have low redlines out of necessity. Those big pistons are heavy, and they travel through a long stroke. They have a lot of inertia. And they have to come to a complete stop at BDC and again at TDC. Remember Newtons first law of motion. An object in motion tends to remain in motion. Reversing the direction of an object in motion instantly and at high speed puts enough stress on it to tear it apart. My 1200cc Sportster has the same redline as an old school small block Chevy. It is only 1.2L, while a 350 Chevy is 5.7L. But it also has 8 pistons compared to the Sportsters 2. The pistons are nearly the same weight, and that is what determines redline.

Something else about a less restrictive exhaust, is that no matter what the air/fuel mixture is, If the carburetor/throttle body is not also made bigger, the engine is not going to breath any better. Exhaust may be able to get out easier, but no more air/fuel mixture is able to get in. There is a direct relationship between the intake and exhaust. I have very little experience tuning bikes, but I have 50 years experience building and tuning car engines. I have built several drag race engines that I was very successful with. Fortunately with those (all old school cast iron small block Chevys) there was not a lot of trial and error, as the information is already out there. You just have to decide what you want out of your engine, do the research, and build the engine accordingly. I have always opted to keep some reliability and streetability over outright power at all cost, since I race only for fun. A drag race engine is designed for top power at redline. Off the line, they are launched at redline, and held there all the way down the track. But while an engine built that way works better on the track, it will fall flat on it's face on the street. You have to rev the crap out of it to even get it to move. Not fun on the street. Another reason I don't like sport bikes. They are built the same way. They make a lot of power, but it is near redline. They are designed for high speed roadracing, not stop and go city traffic.

Whether it is a bike or car, I like a tractable, torquey engine on the street. Power where you can use it. Instant acceleration. Safety and speed limits make it impossible to use high rpm power on the street anyway. And I can almost guarantee that once you have gone 170 mph on a motorcycle on the street, you will have no desire to do it again. It is not fun, it is downright miserable (and scary) I learned that from experience.

[9fingers]

To each their own but from my experience with the carbs on 6 of my bikes, I LOVE having fuel injection! I am lucky and spoiled to be friends with GHG, who is a great guy with TONS of knowledge on tuning the 500. I have always had bikes with Keihin or Mikuni carbs and from my experience AMAL was one carb I would never own. Maybe they are better than they used to be. I know how to jet carbs but it is still a pain in the ass and does not offer anywhere near the tuning potential of a Power Commander with Autotuner. Yes, you need to have some PC skills and some smarts.........or in my case GHG has to have them, but the ability to tune at each RPM range, set the rev limiter at your RPM of choice, and once it is installed, to have it automatically adjust to any further modifications is worth gold to me. I do have the Hitchcocks header pipe and one of their Goldstar silencers, but I opted for an Indian made one in the end, for looks, sound and performance. The power with the Goldstar unit was the best, but the noise was too much for me. But changing the pipes, adding a sock air filter, some custom cams from GHG, the PCV and AT units, and the bike is perfect. Just opened it up a bit and allows it to keep making power all the way to redline, instead of crapping out at 4,000 rpm. You need to change the headpipe as a start IMO. It allows all of the other mods to work as now the engine can breathe. Plus it saves a significant amount of weight.
9fingers

[Narada]

Testify 9fingers!

I went a similar route (see signature line). I've been so happy (and busy) I haven't even set up my auto tune yet. When I do, I'm sure there will be even greater improvement. 

My mechanical experience has been mostly old school automotive, but I've had enough of messing with carbs to last a life time. I'll take EFI every time, thank you.

Edit; P.S. living on the "Left Coast" I've done my own work with Gas House guidance, but the tune was done by a local dyno guy who had never seen an Enfield, much less one with custom piston, cams, ported head, etc...  He did ok, but Auto Tune, a little more Gorilla guidance, and some "elbow grease" is sure to reveal more power! 

[Mad4Bullets]

9fingers' response gave me a chuckle. I installed an EMGO-made wide open Goldstar muffler on my C5 and loved it. Then one day while in a hurry I forgot my earplugs. I had to turn back after a half mile it was torture.  My poor neighbors.  I've since added a slide in baffle to the tailpipe and it's made a world of difference in volume. No more backfiring on overrun either. We learn something new every day.

[suitcasejefferson]

I've been working on carbs all my life, and absolutely love them. They have been proven over more than 100 years of use. They are simple, reliable in the extreme, and except for a couple of pieces, like the float needle valve and seat, literally last forever. They do not require a fuel pump on a bike, nor do they require a ton of sensors and an ECU. You can run out of gas on a carbureted bike and not hurt anything. They can be kickstarted or push started with a dead battery. And I actually prefer the Amal to any CV carb, because it is even simpler. IMO, the simpler the better. I got the whole kit, including the carb, from Hitchcock's for less than the cost of a fuel pump, and it should last well past 100 years if not abused or damaged. There are 100 year old bikes out there still running fine and still using their original carburetors. That would most certainly not be the case with EFI.

[swamp2]

Do you still run points for your ignition?  Much of your same logic would apply... If you're running electronic ignition, you're pretty much screwed without your ECU and battery.

I had to replace the fuel pump on my G5, I think it was like $25 on ebay.  Much of the charm of the UCE is it's anachronistic nature, but I'm not opposed to the application of proven technology to help the riding and ownership experience.
 

[gashousegorilla]

To each their own but from my experience with the carbs on 6 of my bikes, I LOVE having fuel injection! I am lucky and spoiled to be friends with GHG, who is a great guy with TONS of knowledge on tuning the 500. I have always had bikes with Keihin or Mikuni carbs and from my experience AMAL was one carb I would never own. Maybe they are better than they used to be. I know how to jet carbs but it is still a pain in the ass and does not offer anywhere near the tuning potential of a Power Commander with Autotuner. Yes, you need to have some PC skills and some smarts.........or in my case GHG has to have them, but the ability to tune at each RPM range, set the rev limiter at your RPM of choice, and once it is installed, to have it automatically adjust to any further modifications is worth gold to me. I do have the Hitchcocks header pipe and one of their Goldstar silencers, but I opted for an Indian made one in the end, for looks, sound and performance. The power with the Goldstar unit was the best, but the noise was too much for me. But changing the pipes, adding a sock air filter, some custom cams from GHG, the PCV and AT units, and the bike is perfect. Just opened it up a bit and allows it to keep making power all the way to redline, instead of crapping out at 4,000 rpm. You need to change the headpipe as a start IMO. It allows all of the other mods to work as now the engine can breathe. Plus it saves a significant amount of weight.
9fingers

  That's right ! ... .. what he ^^ said !!!   Hahhaha !!          

Testify 9fingers!

I went a similar route (see signature line). I've been so happy (and busy) I haven't even set up my auto tune yet. When I do, I'm sure there will be even greater improvement. 

My mechanical experience has been mostly old school automotive, but I've had enough of messing with carbs to last a life time. I'll take EFI every time, thank you.

Edit; P.S. living on the "Left Coast" I've done my own work with Gas House guidance, but the tune was done by a local dyno guy who had never seen an Enfield, much less one with custom piston, cams, ported head, etc...  He did ok, but Auto Tune, a little more Gorilla guidance, and some "elbow grease" is sure to reveal more power! 

   Come on Narada !!  Get that thing hooked up already, so we can have some fun !   


  Somebody DID NOT say 100 years on an AMAL carb ... did they ?!         I don't know ?  .... 2009 G-5 here in the garage , 53 THOUSAND MILES .    Bottom end STILL tight.  Have things needed attention ?   Sure they have .  BUT... not one issue with the fuel pump or sensors or EFI system .   Just sayin'.... 

  The throttle bodies on these bike's are sized MORE then adequate for the RPM range these bikes see... and even a bit higher !    At 33 mm from the throttle plate to the intake port.    Plenty big enough !      You can put a bigger one on or bore it out ?     But you will have to rev it harder and higher to get about the same output , just at a higher RPM.   And remember on a stock bottom end .... you are spinning around that twenty odd plus pound lump of pig iron at even higher rpms.    A carb with a smaller choke size  then that 33 mm's .... carbs have to choke down in the middle to get that venturi effect going.... will give you better bottom end power, at the expense of mid range and top end.    IMHO ?     Bottom end is certainly not what these bikes are lacking....

[ace.cafe]

Amal carbs are not known for longevity. They are known for rapid wear in slide/body fit. In fact, there is a thriving cottage industry for sleeving the bodies and chroming the slides.

Mikuni carbs are where it's at.

[Mad4Bullets]

That's right ! ... .. what he ^^ said !!!

I had always suspected it, but this recent response proves the GHG is in fact a Classic Bugs Bunny reference. Another Irish Bugs Bunny Fan out there.  Who'd a thunk it Doc?

[gashousegorilla]

That's right ! ... .. what he ^^ said !!!

I had always suspected it, but this recent response proves the GHG is in fact a Classic Bugs Bunny reference. Another Irish Bugs Bunny Fan out there.  Who'd a thunk it Doc?

   Hahaha !  You know , watching this as wee kid after school... NUMEROUS times !    Channel Nine or Eleven i think it was back then ?    Did I think that I would actually grow up to BE one !?      Anyways ... I don't care what SHE say's !!  Once the ball goes outta the Stadium , it's a feckin' home run I tell ya !!!  ....

https://www.dailymotion.com/video/x6tj0co

[Mad4Bullets]

A true Classic, like our Royal Enfields!  Now the forum knows the true inspiration behind our Gas House Gorilla.  Now they know... The rest of the story.

[9fingers]

If any one watches Grey's Anatomy..........I am like Karev.....I tell the truth and tell it like it is. GHG IS A GORILLA! We had lunch one day and I kiddingly punched him on the arm........and bruised my knuckles! It was like hitting STONE! Freaken gorilla arms I tell ya! Also, beware of anything Narada says possible in support of my comments. He is a secret member in absentia of our motorcycle gang, The Long Strokers, a well known and widely feared gang in our area. All 100 members (really 3) are dedicated to RE singles, though we may have to allow 650 twins into the mix. We will discuss in our next open air meeting, where we will maintain at least 6' social distancing. Weather is getting good and I am recovered from surgery enough for short rides, and hopefully long ones in 2 weeks. Frogman8, you ready to ride?
9fingers

[gashousegorilla]

   Oh stop .      Come on now.   Why... I screamed like a little girl inside when ya did that !? 

[Narada]

 "Come on Narada !!  Get that thing hooked up already, so we can have some fun !    "

Speaking of modified exhaust, I just decided to hook up my Auto Tune (purchased last July) and realized I need to get someone to TIG my Bung!  Worse than that, I need to ask where my bung hole should be? 

My Hitchcocks head pipe has a small bung hole for the stock O2 sensor, but the Auto Tune sensor is a "wide band" right? It's a larger ID bung than the stock one (new bung is provided in kit).  I could hog out the stock size bung and put the new and improved larger one in its place, but I seem to remember that the wide band bung likes to be further down stream... is that right? How far down should the wide band sensor be from the top? 

I could also MIG weld the new one in myself, but I'd hate to mess up that shiney pipe! The bummer is, if I want it TIG'ed I'll have to wait until this virus shut down is over... that might be a while. 

 "Also, beware of anything Narada says possible in support of my comments. He is a secret member in absentia of our motorcycle gang, The Long Strokers, a well known and widely feared gang in our area."

I couldn't agree with you more 9fingers!   Long Stroker with a Dome Top!  Social distancing (in absentia) is no problem! 

[olhogrider]

I can't answer your question but I did laugh my ass off at your bung hole problem

[9fingers]

We need to be careful in discussing our bung hole problems..............some people might get the wrong idea.............
9fingers

[swamp2]

Dynojet's AT-200 installation instructions read as follows...

Positioning the weld bung in a location where multiple cylinders collect is the preferred location. If your application has a “2-into-2”design, it’s recommended to position the weld bung/sensor approximately 6” from the exhaust port on the respective cylinder you wish to tune.

Since we have a "1-into-1" design where it's pretty clear what cylinder we wish to tune, I'd say the 6" from the exhaust port guidance would apply.

[gizzo]

Depends what instructions you read, they say 6" or At Least 6" from the exhaust port. Mine's 9" and seems to working well. As you can see, I wasn't too fussed about messing up the chrome. It's f... ed anyway. I'll get a new stainless one when the current silliness ends.

[gashousegorilla]

"Come on Narada !!  Get that thing hooked up already, so we can have some fun !    "

Speaking of modified exhaust, I just decided to hook up my Auto Tune (purchased last July) and realized I need to get someone to TIG my Bung!  Worse than that, I need to ask where my bung hole should be? 

My Hitchcocks head pipe has a small bung hole for the stock O2 sensor, but the Auto Tune sensor is a "wide band" right? It's a larger ID bung than the stock one (new bung is provided in kit).  I could hog out the stock size bung and put the new and improved larger one in its place, but I seem to remember that the wide band bung likes to be further down stream... is that right? How far down should the wide band sensor be from the top? 

I could also MIG weld the new one in myself, but I'd hate to mess up that shiney pipe! The bummer is, if I want it TIG'ed I'll have to wait until this virus shut down is over... that might be a while. 

 "Also, beware of anything Narada says possible in support of my comments. He is a secret member in absentia of our motorcycle gang, The Long Strokers, a well known and widely feared gang in our area."

I couldn't agree with you more 9fingers!   Long Stroker with a Dome Top!  Social distancing (in absentia) is no problem! 

    Hahaha !!!     Right where the old one is is just fine.    Like swamp said, it's a single.   I never had a problem at the stock location.  Drill/ grind out the old bung hole ... Hahaha !.... and Weld or Braze the new one right in it's place.   A  mig or a splatter box is fine Narada.    Just mask off the surrounding area  with some leather or heavy strips of duck tape.   Clean up the weld with a grinder and spray a little  high temp  silver BBQ  paint on it , if you want to dress it up and keep the weld from rusting.      When you weld it, just make sure you put an 18mm bolt or plug in the hole , of the bung hole .. ... so as not to get any weld splatter on the treads inside ... the bung hole.    You'll notice  on the bung hole they sent you,  there is shoulder on one side of it.   That shoulder fits inside of the pipe so you don't have gap when you weld around it.     

[suitcasejefferson]

Mikuni carbs are great. As long as they are not CV. As for Amal, I'm sure mine was made in China. It has lasted more than 8,000 miles without a problem. But you can buy a new one for about $50. The price for a NEW Royal Enfield fuel pump is over $500. As for points ignition, I would love to have points ignition and a magneto. If I weren't disabled I would be happy with kickstart only. I just love using the tickler on my Amal carb, and getting gas on my finger. It is, after all, a MACHINE. I admit I waited too late to buy a RE. I wish I had bought one back in the early 2000s. But what attracts me to the RE is not only it's looks, feel, and sound (through an aftermarket exhaust) is it's lack of technology. I own 6 bikes, and none of them have EFI. Or ABS. Motorcycles are my ESCAPE from technology, at least the electronic kind. I used to own a 1966 Triumph Bonneville. One of the biggest mistakes I ever made was selling it. I am looking into getting an Ironhead Sportster. While I have a 2006 carbureted Sportster, it still feels a bit to "modern" Something more crude and primitive, with some rough edges. And parts are plentiful for those.

[9fingers]

For what it is worth, I agree with everything SCJ said, except the part about tickling the carb and getting gas on my fingers.
9fingers

[Ove]

Can't believe a 1966 Bonneville is more crude than a 2006 sportster..!

[9fingers]

Being a former and current trials rider...........I have never even ridden a Harley.
9fingers

[swamp2]

For what it is worth, I agree with everything SCJ said, except the part about tickling the carb and getting gas on my fingers.
9fingers

Yeah, I felt that way for a long time, but eventually I got sick of oil leaks, tickling carbs, kick starting fussy bikes.  Had probably (at least) 20 Triumphs over my bike riding career, vintages from '56 to '75.  Singles, twins and triples.   Yes they're charming in a crude sort of way - but why put up with that crap if you don't have to.  If you want to get over your love of Amals and points, try owning a Trident for a while, it'll cure you in a hurry.  Replacing the cap in a Lucas K2F magneto is an expensive proposition, and it is an inevitable requirement.  I can't begin to count the bruises my 441 Victor gave me trying to kick start the thing and catching the inside of my leg on the oil tank corner.  I never want to own an old British bike ever again.

That's exactly why I got a Royal Enfield UCE - I really missed the look and feel of having a classic bike, it's just that I've gotten less tolerant of that kind of "character" in my old age (61).  I am far from a technology worshiper, but there's nothing even remotely high tech about electric starters, or EFI, or electronic ignition or disc brakes anymore, or CNC produced parts that don't leak oil.  To me, they all make the "classic bike" ownership and riding experience much better. 

If you still like points, carbs, etc that's perfectly fine - just not my preferred thing anymore (actually several of my bikes still have carbs, and 2 of them still have points).  To each his own...

[gashousegorilla]

   I would NEVER go back to carbs willingly .  Hahaha !  They are just not compatible with our ethanol laced fuels in the US.  It just does horrific things to them.   Hours and hours spent on cleaning them out over the years !    You can have them !    If one has REAL gasoline near them ... consider your self lucky.  Because most of us do not.  And when I ride my bike ... I just want to ride it , and not have to think about hunting down real gas.   Pull into any station and i'm good to go.  Although I would rather not to use it...   I've had no ill effects from using 10% Ethanol in my with EFI Enfield's  for the past 11 years.   The bikes and gas in the tank  don't sit around long enough for that to happen.    But I DO get it.... there is nothing like setting up a bank of Carbs perfectly and the motor runs sweet.    But there is WAY more likelihood of that mechanical soup can with holes in it malfunctioning, with corrosive fuel in there, then there is with EFI. 

   A quick look around the net shows that an Amal Concentric is about 200 bucks give or take.   A replacement fuel pump for an Enfield ?   About 70 bucks...

https://www.highflowfuel.com/i-35459720-quantum-t35-intank-fuel-pump-for-royal-enfield-bullet-500-2006-2016-replaces-571052.html   

[ace.cafe]

I can go either way, carbs or EFI, as long as I can get control over the adjustability for the EFI.

[Frogman8]

Frogman8, you ready to ride?
9fingers

Is said Bungholes have been appropriately dealt with - wiped, washed or even sealed (must be painful, not to mention a bit inconvenient), I'm ready to ride any good day.
The new old G5 needs some miles on those new tyres.