Mikuni RS Series vs. Mikuni VM33s on a GS1150ES

[Hap Call]

I'm with Ray on this one. I've been running VM33 carbs on my 1166 GS1100 for over 20 years and have never had a problem - when set up right they make plenty of power and are smooth across the entire powerband.

Hap

[Strangelove9000]

Bumping and RENEW this thread

Greetings,

Why start a new thread when this one discusses exactly what I was searching for??

This is my first post here!! (after several months of lurking) First, I must say there is an abundant wealth of old-school GS knowledge here, which I think is just Awesome!

Anyway... I am once again building out the engine of what must be one of the finest motorcycles ever created by mere mortal beings. I must stress that this is NOT a "dragbike" project. I am not going to make any compromises that would sacrifice the all-around drivabilty of this machine. I like everything this bike gives in such a (perfect?) balance of performance, handling, comfort, and style.

I just want 25-30% more of everything? And some people call me crazy...

So.. I have begun with a red 1983 GS1100ED with about 20k miles. It's not bad but needs help in a few areas. Cold starts puff a little too much smoke for me to be happy with, so it was off with the cylinders. Rings and a hone would probably keep things happy for another 20k miles but why tear all the way down and not go with some nice Wiseco 78mm (1261cc) units @ 10.25:1. To keep valve lift somewhat in balance with the increase in CC, I think the Web Cam grind #223 would be adequate?

The stock carbs are junk for all practical applications. Even with this planned increase in displacement and compression, from what I have heard here and elsewhere, the Mikuni 40mm RS flat-slides are too much. Open throttle at low RPM's results in the engine "falling on it's face". 38's may be on the fringe too.

Many (many) moons ago, I built out another GS engine to similar specs and used the round slide VM33 "smoothbores" with tremendous success. However they are getting hard to find in decent condition. Are there even many parts available for these (discontinued) units these days?? I have seen gaskets and a few jets for the 33mm's but thats about it. What do you do with a worn slider or linkage?

Age/condition and parts shortages for the 33's have forced me to consider a set of flat slides. As I have heard in other discussions, 36mm seems to be a happy medium for displacements in this range. I have also heard people say that the round slide carbs can flow more air than a flat slide with the same throat diameter? Anyone believe or experienced that?

Off on the total bleeding edge of reasoning, I have seen several set's of GXSR throttle bodies on Ebay for pretty cheap along with programmable control modules. I have been wondering if am I barking up the wrong tree with carburettors? Anyone here have any experience with a fuel injection mod on a GS1100E? How tuff could it be?

What are your thoughts?

Peter