Yamaha TRX850 Enthusiasts Forum

Has anybody looked at or had the standard carbs bored out to say 40mm? I was having a good look at it last night and I reckon it could be done. Question is, does this upset the balance of the workings of the carb? Obviously it would need a re-jet but what about the basic function? It would give a 10% gain in cross section.

Also, when they pair the two FCR or similar Mikuni carbs what are they actually linking other than the throttle linkage? ie. vaccuum hoses, fuel pump ??? etc.

Hmmm, maybe it would be possible but I`m not sure if any drillings through the carbs bodies would be exposed. The FCR`s are more of an improvement not only because they are larger but because your throttle cable / s are directly linked to the flat slides.
The CV`s (stock carbs) relying on the vacuum above them to lift the slides.
You are more in control with flatslides.

Yeah, good points. Need to investigate more. I suppose the CV's allow more margin for throttle control error for teh novice. Thanks

devlin wrote:Yeah, good points. Need to investigate more. I suppose the CV's allow more margin for throttle control error for teh novice. Thanks

If you want bigger CV carbs, then bolt on some Firestorm carbs. But FCRs will still be waaaaaay better

Ok. I'll forget about it then. I've decide to wait and do a carb swap, head job and headers installation all at once when I can afford it and just get what I have now running a best as possible.