88trx 250R sputtering in Pwr bnd?

[revman440]

I just did a rebuild on my R. I added a CR 500 carb with a 162 main jet and 40 pilot. It starts first kick, idles nicely, but when I get running and into the power band she spits and cuts out a little as Im accelerating?. Its weird, I have never seen a 2 stroke do that?

Is it because my main is too small?

[methyman]

What is done to the motor? It is probably a PWK 38. Are you at sea level?

[revman440]

motor is stock, in NY

[troybilt]

air filter clean and is the lid off the box?

This is the best resource for figuring jetting woes... I have the same problem on my Sparks motor, my plan is to go down on the main until the sputtering goes away. The needle also comes into play in this range. Make sure you only change one thing at a time. I would setup the air screw and work thru the jetting just as described in the below article.

http://www.duncanracing.com/TechCenter/KeihinCarbJetting.pdf

[Fear250r]

Sounds like what my bike did when the cdi went.

[revman440]

air filter clean, but cover on box

[methyman]

Take the lid off and run it and see how it runs.

[wild250rman]

check the counter balance bearing carrier on the stator side make sure none of the ears are broken or cracked and all of the bolts holding it are in place and not broke either. Did it have any issues before the carb. switch? if so then it is your jetting and did the used carb. work fine when on the donnor bike. does it have the correct size slide the slide cutaway that can also make a difference? been a while since i run a 38 on a stock 250 motor to remember the correct pilot,needle, main and slide size to tell you. lots of good tuners on here could point you in the right direction. one thing is for sure it will run good once you get it dialed in.