KZ 900 Rebuild

I am rebuilding my kz900 with new pistons. The new cc is 1045 with new 118 cams. I have been getting several people telling me the 28 mm carbs will not be large enough to make use of the larger bore and cams. The people who sold me the cams are telling me I need rs34 flat side. Wiregeorge says these are too large. Looking for someone who has done this before. Thanks

I think that those carbs would be fine. They might not be optimum like a 29mm smoothbore might be but they will not disappoint you. I would more worry about the 1045 kit for a KZ900. I am not sure how thick that will leave the sleeve walls but you might experience some overheating. I hope that someone around here has done this combination. I know it is the largest bore before new sleeves are required and that leads me to think that you will be approaching 1.5mm (.060")wall thickness. This thickness in my experience in the larger bikes I have done led to overheating. The small amount of power you will get with the extra 30cc is not worth the potential heartache. You would do and fair much better if you did some head work and allowed the engine to breathe better. The percentage of HP you will gain by that over the extra 30cc is night and day. I believe that Larry C the build guru around here will agree with me. With 30cc you can only expect about a 3Hp increase if you are lucky.

For your build, preferably 29-31mm and you'll be golden.....
Same time, 28mm will do just fine....

Also depends on your riding style... you going for low to mid range or WOT... RS34's or Keihin flat sides for that matter, beautiful carbs but.... truly designed for WOT throttle racing....

As provided to me my Buzz @ Dynoman and Larry.... based on my description of what I had in mind...they both replied the same, 1015cc kit, .365 cams, 29mm CR specials with a Kerker /1.5" baffle and a Larry C head rebuild/P&P.... you'll just love that combo....

And they were dead nuts ON the spot....

PM Timebomb for the 28's are what they use for class instruction & hands on where he teaches...

OMR

28mm carbs will be fine. also i have motors like this with TUNED rs 34mm mikuni carbs also doing great.

could u elaborate on headwork and its cost... i run astock kz1000 78

I have not done anything except replace the oem valves with a valve job at this time. Several of the post on other forums talk about porting but did not talk about cost. Guess its all in how far you want to go. That might be my next project for the coming winter.