on my carb the choke and idle are on the same post and when i turn it to raise the idle nothin even when i turn it and it wont hold an idle unless i give it the gas to keep it up what is the recomendation to fix it i was thinkin a carb rebuild because the spring that controls the flow maybe not as tight any help be great and what is the correct compression on a stock ,but ported and polished head and jug

 

I know this may seem like a dumb question but, is the engine warm when you are trying to set the idle? The only way to really fix the problem is to rebuild the carb, which probably isn't a bad idea anyways. As for the compression, i think around 190(don't quote me on that, may also be 185). The porting and polishing shouldn't effect that, unless you have a thinner head gasket in.

 

thanks ,,, thats what i figured ,,no not when its warm it wont hold idle when warm or cold i have to keep on the gas or it stalls out and when i turn the idle screw nothing ,no up or down in idle change

 

The stock carbs on the 250Rs suck. Especially when they are the original (old) parts.
You can only rebuild so many things on the stock carb. I don't think the float valve seat can be replaced.

IMO, you should just go get an airstryker carb. Better carb, and you don't have to mess with the choke/idle screw. They are separate on the airstryker.

 

I have the stock carb, and mine will idle all day. I will agree they can really moddy, but what isn't on these old quads. Did you try adjusting the pilot screw(my be called something else) its the screw toward the back of the carb. If you play with that it makes slight adjustments, to the fuel air mixture which would effect your idle. I would turn it back to the stock specs, you'll have to look in the manual, but then play with it both ways fromt here. It might help.

 

make sure the air/fuel screw is around 1.5 to 2.5 turns out from seated. if not try that first. my r is ported with higher compression and i tried a 38 flat slide mikuni with some degree of success. but put the stocker back on it and got WAY more response with the the smaller carb (velocity). im cool with stocker on mine,2 year old plug (no fouling).take it apart and check it out. mine idles for about 15 seconds and stalls (just the way i like em ). CRISP BABY CRISP[img]i/expressions/face-icon-small-happy.gif[/img]

 

The stock PJ carb is a POS. The PWK is a much better design, and works much better for throttle response, etc. (Unless you oversize it too much)
The idle adjustment for the PJ is marginal at best, and unless all the factors are just perfect, forget getting it to idle.
Jetting is also difficult to keep perfectly dialed in (VERY sensitive to Temp/elevation changes)

Best mod I did to my R was to upgrade the carb, then pipe, then ........

 

Hey dune where did you get your pwk carb, and what size did you get?

 

ok my question to that is i have the stock carb w/ a 148 main jet what carb and size do you reccomend , i have a new stock bore with a port and polish

 

I purchased mine from T&N performance in Roy, UT
38mm, but my port work is far from stock... A 36mm would be my weapon of choice otherwise...

My $.02