WR 250F stumble

New 09. Bought it 2 weeks ago. Finally had time to ride it Saturday afternoon, after the dealer was closed, so I couldn't call the dealer and ask.

The dealer removed the AIS, uncorked and rejetted it for me. I told them to jet it for a QCore. When the engine is fully warmed up, the stumble happens at 23mph in 3rd gear. I'm guessing that the engine is turning around 3500 RPM.

Every bike has it's ideosyncracies. This one is new to me. So I just don't know how smooth that engine is. It pulls hard and I'm very pleased with the power this thing makes. Other than the stumble, I'm very pleased with the WR 250.

While I'm on the subjet, If I put a plate on this bike, and ride it on the road, if it's jetted properly, how smooth will this thing cruise at a steady rpm?

Bike shouldn't stumble. It's probably not jetted correctly.

I heard unplugging the tps sensor on the carb cleans it up. I have not done it myself yet, but I also have a hard time keeping steady rpms with very low throttle positions. Everywhere else its fine but if I try to just put down the road in low rpms it either speeds up or drops off. Is this what you are experiencing?

As has been refered to above by TrillXb:

If you are talking about some kind of feeling like the bike is misfiring or skipping while cruising on flat ground with a steady throttle, mine does that, too, and I've read enough comments on that to believe that it's common.

Since it only will do that while cruising from one trail to the next while putting on the street, I don't get concerned about it, and once on the trail and doing some actual off-road riding, it vanishes and runs as it is expected to. :thumbsup:

RPM and speed means nothing. What is the exact throttle position relative to total travel? Was the bike on a flat road or incline? Steady throttle or accelerating?

I took the bike back to the dealer on Mon. We had a bit of a miscommunication. I told them to uncork it and jet it for a QCore. They jetted it for the stock can minus the pea shooter.

After the proper jetting the bike runs as it should. Low end bog is gone. These things aren't meant to cruise, and mine is no exception, but it is as good as it's going to get. Which isn't bad...

As a side note. I an very pleased with the power this lil WR cranks out! What a cool bike. I just love it!

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