GS1100e Smoothbore/slingshot carb advise

[limeex2]

I have a GS1100e that I am modding into a naked franken bike/hot rod.I also have a GS1100es that will be more of resto type bike. Both bikes will have pipes(choice of a Bassani Superbike pipe or a Yosh Street or a Yosh Race pipe) I have a set of slingshot carbs that were rebuilt by a member and am contemplating getting a set of 33mm smoothbores. I also have 82 GS1000s cams and rotor. My question is for the GS1100ES. Would I be better off using stock carbs with a pipe and pods, or using the slingshots and getting the 33mm for the Hot Rod bike? Also what would be the best set up(H.P. and torque)for the hot rod? Any and all of your suggestions will be helpful and appreciated, especially Ray and all the rest of you motorheads.Please help me choose a route, this will over whelm me. I am serious! The ZRX1200 is next..... Thank you

[Fjbj40]

The vm33's are not very streetable. Once you are above 3500-4000 they are great. I had a set on my 1085 and swapped them for GSXR 34 flatslides, way more streetable in many ways.

Daryl

[rapidray]

The vm33's are not very streetable.
Daryl

NOT true at all!!! The 33s actually work VERY well on street bikes. You just have to KNOW that you don't slam the throttle wide open, you roll into it. They work well on even bigger motors that make more vacuum to compensate for the lean condition created when slammed open. The 34/36 RSs work well also but back in the day, when the 33s were all we had, they worked VERY well on stock motor 1100s with just a pipe. I have run & tuned them on more than 20 1100s & 1150s. I actually prefer the 33s to the RSs as the RSs are VERY leak prone if ANYTHING gets in the fuel system. I will NEVER run the RSs on any of my drag bikes again!
Ray.

[stetracer]

NOT true at all!!! The 33s actually work VERY well on street bikes. You just have to KNOW that you don't slam the throttle wide open, you roll into it. They work well on even bigger motors that make more vacuum to compensate for the lean condition created when slammed open. The 34/36 RSs work well also but back in the day, when the 33s were all we had, they worked VERY well on stock motor 1100s with just a pipe. I have run & tuned them on more than 20 1100s & 1150s. I actually prefer the 33s to the RSs as the RSs are VERY leak prone if ANYTHING gets in the fuel system. I will NEVER run the RSs on any of my drag bikes again!
Ray.

Yep CV carbs were invented for riders who did not know how to control their throttle hand.

I have actually had great success with RS carbs never had a leak problem with them and they work great on drag bikes too you just have to take out the accelerater pump rod when using a 2-step on the launch. I would never use a set of 33mm carbs on a 1150 as the intake port is 34.5mm stock and you never want to have a larger intake port than your carb size because it will slow the air speed to slow down and allow the fuel and air to expand and the fuel to turn back to a liquid.

Limeex2
You always want your carbs to be larger than your intake port. Your carbs should be 1 to 3 mm larger than your intake port depending on what your building the bike for 1mm larger for road racing and 3mm larger for drag racing. I use my bikes for both street and drag racing so I put carbs on that are 2mm larger than the intake port. The Keihins FCR's are really nice carbs also in fact I like them best but are pricey. I also use pingle inline fuel filters on all my bikes to keep anything out of the float valve. Blending the intake rubbers to the carbs and intake port will help big time also.

[stetracer]

image.jpg
This is what you want it to look like. This is a set of 40mm Lectrons on a head ported to 38mm. Now you don't need carbs this big I used this for an example so you can see the blended intake manifold

[Fjbj40]

The OP asked about carbs for the "resto" bike. So he wants something that will be easy to drive, "like factory" hence resto.

I frigged with the VM33's for a whole summer, and yes they are fine if you gently roll on the power to avoid the flatspot that is associated with that style carb. Now you guys have probably got a lot more experience than me and may be able to make the carbs work better than I can.

All I know is all the running issues I had went AWAY as soon as the GSXR carbs were installed. No more hanging idles, no more farting and popping while idling at stop lights. Not like a stock style bike, which is what "resto" means.

All the best Limeex2, but if you want a factory style behavior then the VM33's are not the way to go in my experience. I am sure others will speak differently, but sounds like you have a Ferrari for the fun days, its nice to have a Mercedes for the relaxed easy days.

My 2 cents,
Daryl

[stetracer]

The OP asked about carbs for the "resto" bike. So he wants something that will be easy to drive, "like factory" hence resto.

I frigged with the VM33's for a whole summer, and yes they are fine if you gently roll on the power to avoid the flatspot that is associated with that style carb. Now you guys have probably got a lot more experience than me and may be able to make the carbs work better than I can.

All I know is all the running issues I had went AWAY as soon as the GSXR carbs were installed. No more hanging idles, no more farting and popping while idling at stop lights. Not like a stock style bike, which is what "resto" means.

All the best Limeex2, but if you want a factory style behavior then the VM33's are not the way to go in my experience. I am sure others will speak differently, but sounds like you have a Ferrari for the fun days, its nice to have a Mercedes for the relaxed easy days.

My 2 cents,
Daryl

I was explaining how to pick the proper carb size for his head and letting him know that the aftermarket carbs work fine. But if he wants the ease of factory CV carbs they are available in 34, 36, 38, and 40mm. The 38 and 40mm are harder to find though

[limeex2]

I have access to a set of RS's 33's for $300. I want the bike to be fast, but in the end,it will still be a street bike and from my roadracing days, I dont like to babysit a finiky bike. I also have a set of flat slide Edvac's that are dyno'ed to the Bassani,but they are race only,no idle circuit. FCR's would be nice,but if I go that route, I will put them on the ZRX. How about the cams I have? How can I identify the cams? I have had them packed in grease for 30 years and some parts of my memory are not serving me well! lol. I have seen the local dyno guy tune his way around a lot of stuff, but the money spent on a extra set of carbs would go a long way towards suspension goodies.

[stetracer]

I have access to a set of RS's 33's for $300. I want the bike to be fast, but in the end,it will still be a street bike and from my roadracing days, I dont like to babysit a finiky bike. I also have a set of flat slide Edvac's that are dyno'ed to the Bassani,but they are race only,no idle circuit. FCR's would be nice,but if I go that route, I will put them on the ZRX. How about the cams I have? How can I identify the cams? I have had them packed in grease for 30 years and some parts of my memory are not serving me well! lol. I have seen the local dyno guy tune his way around a lot of stuff, but the money spent on a extra set of carbs would go a long way towards suspension goodies.

No such thing as 33mm RS carbs. Your head intake port is what determines your carb size. What has been done to your head? Is it ported? If you want to give me a call I can explain it better to you. 941-391-1410 my name is J.D. Kittredge.

[trippivot]

33's are my last choice, for a smooth idling / relaxed riding

VM 33mm mechanical round slide smooth bore carburetors are absolutely TERRIBLE STREET CARBS!!!!!!!!! WORSE than 29's - or individual body even# venturi dia. VM carbs by means of the idle circuit

The special 33mm's make excellent power -anything over and above 1/2 throttle you can accurately tune (micro tune) to any elevation/temperature /density altitude

Try to get them to consistently idle - problem.
try to blip your engine up to 4500 RPM and return to idle - problem
I like to mention the revvs do not quickly return to idle between gear shifts - power shifting only no more relaxed shifting

change the slides for a leaner/richer cutout - lift the needle - change the air bleed - try every pilot jet - (and be sure you have the proper pilot jet) - from 15 to 45 - and if your time is as valuable as mine is - after the 8th or 9th attempt you realize the vm33 smoothbores are for all out racing not Sunday afternoon cruising

now don't get me wrong the bike is going to run - but if it dies at a stop light nothing is wrong - change the idle speed and you can let it over-rev at 2200. what do all the smoothie riders do??

babysit your throttle aka throttle jockey it -- like they say you gotta love them. in my experience they suck for relaxed riding

properly installed/tuned stage 3 CV's will return the smoothest transition from idle to mid range and back to idle the best M.P.G. come from- mikuni BS 32/34/36. 2nd choice RS flatslides but these are noisy and have a set of complications all of their own - got to love these too -I do - BOTTOM LINE you will never get refinement or the economy as CVs' give the inline four style engine - not even F.I. systems can come close.

CR, FCR, exotic and over priced. - -2 methods to determine carb size and both are wrong most of the time - thanks to Cameron and Jennings - intake valve diameter method or cylinder volume method.

[limeex2]

Mr Kittredge, I will give you a call. thanks again for everyones input and ideas. This will be a fun build and get me through the winter doldrums

[stetracer]

[QUOTE=trippivot;
CR, FCR, exotic and over priced. - -2 methods to determine carb size and both are wrong most of the time - thanks to Cameron and Jennings - intake valve diameter method or cylinder volume method.[/QUOTE]

I will agree with you on the 33 smoothbore's never really liked them as far as the RS carbs go I love them and have them down pat very streetable no hanging idle smooth transition and no popping on deceleration and they run like a raped ape. The FCR's are some what new to me but they are fairly easy to tune but just as noisy as RS carbs. I am a bit of a carb nut. The carbs I have right now are Factory CV's 36, 38, and 40mm, RS's 38, and two sets of 40mm, FCR's 39, and 41mm, Lectrons 38 and 40mm. And no I don't want to sell any of them. As far as my way of chosen carb size I learned most of what I know about building motors from Russ and Carl Nyberg of C&W Cyclework. They used to give me parts at cost. I haven't seen them in years though. I miss them guy's. I guess everyone has to retire someday. I still see Carl Jr. or Doobs as we call him from time to time. Sorry got off subject anyway if you think about it it the same thing the factory's do. Take the 1150 for example it has a 34.5mm intake port and came with 36mm CV carbs.

[rapidray]

I'm not sure what problems you guys have had with the 33s but I never had issues with them. I street rode, road raced and drag raced them & had no drivability issues whatsoever. I know how to tune them very well so maybe that was the difference, I don't know. I will pay 300 bucks for just about every set I can get!
Ray.

[stetracer]

I'm not sure what problems you guys have had with the 33s but I never had issues with them. I street rode, road raced and drag raced them & had no drivability issues whatsoever. I know how to tune them very well so maybe that was the difference, I don't know. I will pay 300 bucks for just about every set I can get!
Ray.

My biggest problem with them is they were just to small and had round slides. I did have a set on my CB1100F but after I built the motor they were to small.

[trippivot]

I would suggest Dyno jet stg.3 kit , Cv's and pods -- along with your 1000S cams and rotor - will be great for your ES and if you decide to buy a set of 1260 pistons get some 0.348" cams your configuration will still provide plenty of power at W.O.T. and a bike you can ride in the toys for tots parade.


BTW maybe get the smoothies - send them to Ray , start a thread , post the results, I'd like to learn what I'm doing wrong, because he is sure we are ALL having problems tuning our 33 smoothies for drivability. All of us? $450 gets a fully rebuilt set - I have 2 banks-