You can pick up good clean 38mm PJ's from any dismantled late 80's early 90's CR or RM 250. Mine was from an early 90's CR and once jetted and needled correctly was a dream setup. The range of needles is awesome for the Keihens and you can fine tune em to perfection compared to the Mikuni. The 39 PWK for what ever reason do seem a pain in the butt to tune.

Kiwi

 

Go with the 36mm the 38mm will be to much for a stock motor with just a pipe!! If in dought call trinity and talk to Harry.. The 36 is the way to go. The 38 will not give the same throttle response as the 36mm on a stock motor.
The 38mm will work,, but will NOT perform as well.

 

Will the 36 still work well with some porting? I was considering having some head work and some high perf reeds done next season when it needs its next rebuild. Any idea were to start with the jetting on the 36?
thanks again

 

HUMMM 38 too big,My ex has a Lt250 with a Mikuni 41 smooth bore flat slide carb and it react's better then the Kehin she did have on it,and does not suck the gas down,plus you can fine tune them too,before the lectron carb mikuni was the carb I had,but to each his own I guess.....Zilla

 

Ok..this may be a really simple dumb question but I want to ride this weekend and just need an answer. I picked up a Keihin PJ 36MM carb to replace my broken stock carb. Now my question is what do i do about the fuel line. The fuel line attacment on the carb is about twice the size of the stock.

 

Ok get a larger diameter line for the carb and run it up to the petcock (fuel on/off lever). Take the old small diameter hose and cut a small piece out it so it goes over the petcock then slide the large hose over it and clamp it down.