CRF's Only Forums

Good day Gents,

Popped the top-gasket on my '06 250X. Fixed the whole lot but now find myself with the following problem. The engine stars-up easily. Revs run-up but then it immediately dies (often with a backfire).

Checked:

1. Spark is good.
2. Fuel supply is good.
3. Air supply is good.
4. Valve clearance is good.

Any thoughts or someone had a similar experience ?

Regards

Smiley

Have you eliminated bad/old gas ?? , and have you confirmed the timing is correct ??

Thanks for the info.

Will check and give feedback.

Does it immediately start back up after it dies?
Make sure there is plenty of gas in the tank, and open the fuel bowl drain screw and let it drain into a pan.
I am curious to see if there is a continual uninterrupted supply of fuel available, or if the may be a restriction somewhere.

Hallo,

The problem seems to be more than just starting-up and dying immediately. The exhaust header also gets red hot within seconds, motor is running rough and backfiring.

First-off I'm going to do a wet and dry compression test to see if it's not a bad valve.

Then I'm pulling the carb for a complete dismantle, clean and reset.

I'll report back what I've found. Thanks for the suggestions so far.

Sounds lean. Make sure your float level is correct, no air leaks (intake boot), and your hot start plunger isn't stuck open.