Jetting 88' CR 250

[turbonetics88]

Ok first off i'd like to say hi to all of you out there that decided to look into my thread, at the moment im trying to get my 88' CR 250 jetted perfectly for where i live now.

Im at 5,000ft elevation and air temp is around 60-80 degrees out at most times and no humidity because i live in Nevada.

the stock jetting on my bike as said in the manuel is (185 Main Jet), (62 Slow/Pilot Jet) (4th Groove On Needle). and (40:1 Fuel/Oil Mixture)...

Now what the only thing different now in the bike is that i put a 175 Main Jet and have also raised the clip on the needle to the top to the the leanest point and yet my powerband still hasnt gotten to much better, should i lean it out for better performance because it has good low end torgue but mid range-top end is kinda crappy and there isnt really a powerband.

Any suggestions would be most appreciated and the only thing i can thing of as the culpret is the Jetting, everything else is fine... :think:

 

[Big Bore Stroker]

Have you checked your float level?? If the float level is off jetting is going to be hard to adjust correctly.

 

[turbonetics88]

actually i have never check the float level before but i have done it on a previous bike so i know how to do it and the manuel will tell the proper height so thanks though i never really though of the float as the problem, so what else besides the level of it being wrong could maybe the problem, for example today i was riding and 1st and 2nd gear have NO mid range-top end power i give it gas then after about 1/4 throttle the bike just runs out of power and then i have to shift to 3rd to get more power and have it not bog down...i also forgot to mention that it has what looks like a CR 500 Pipe on it, it isnt a 250 pipe because it wraps around the frame more unlike a 250 pipe, i also have a 50 Tooth Renthal Rear Sprocket and a 13 Tooth Front Sprocket...so could that be more of a problem, from what i hear the bike was raced so i would assume that was the purpose for the sprocket and pipe but i think thats why i dont really have a powerband in lower gears, i have good low end torque but not a powerband

 

[John Cena]

Have you checked to make sure the exhaust power-valve is opening and closing? How old is the piston?

 

[ThunderGoat]

well i have a 88 cr 250 basically stock and have a 53 on the rear 13 on the front and the ****er is all top end, hardley any low end just powerbands like hell. any wasy check the power valve and check the reed valves make sure they in right position and working. and also if its been raced pressure test cylinder to see if it has any pressure in there might need new piston and rings

 

[turbonetics88]

ok today i went out and bought a 55 slow jet and a 180 main and only put the 55 in and the bike runs ALOT better, so much low end torque and now finally has what i would say is a powerband i guess half the reason why it was acting wierd was because the slow jet just fell out when i took the carb bowl off meaning that it wasnt even really screwed in then so im glad it wasnt something more serious that would have costed alot of $$$ to fix thanks for the input i'll keep it in mind because i'll have to start re-jetting due to the winter rolling around and it snows where i live so its a huge jetting issue here thanks though