1988 Suzuki RM250 Carb help

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9/16/2017 2:20 PM

I'd like to replace the carb on my 88 with either a new Mikuni or a Keihen carb. The stock carb is a Mikuni flatside 38mm. Can someone recommend a good quality reliable replacement carb for these bikes? Will a non Mikuni carb fit in place on the bike with minimal effort or will major reconstruction be needed?


9/18/2017 4:55 AM

I had problems with the stock mikuni on my 88 rm 250 build, cleaned, rebuilt, new everything, still flowing too much fuel, would start to clean out if I turned the petcock off, stopping the fuel flow until it eventually runs out of gas in the carb. Fuel was not running out of the overflow tube, indicating float level too high. I do remember another member stating the needle valve seat can leak into the bowl & it can be made to seal better by sanding/buffing the area where the plastic seat/oring sits in the body. I have not tried this yet, as I became so frustrated with the mikuni, I had a stock keihin from a 96 cr 250 laying around, stock jetting from the 96 Cr, bolted right on, started up first kick, runs great, that carb is still on my 88 rm 250. I suspect your carb as mine has an internal leak, allowing too much fuel flow.....For reference, a carb off a 96 cr 250 will fit right on. I have been watching your build and was waiting to see how your carb worked....off course a new airstryker would work as well, just make sure you take the measurements of your stock carb as thre are short & long body carbs...


9/18/2017 2:16 PM

I can't remember if it applied to the 250 as well, but the hot setup for my old RM125 apparently was to swap the Mikuni carb for the Keihin which came on the CR125s. (I never did it.) It would not surprise me to hear the same was true of the bigger bike.


Braaapin' aint easy.