SURGING @ 1/4 – 1/3 THROTTLE

Here’s the issue, I roll on the gas slowly about 1/4 to 1/3 the engine kind of surges, but if I stab it no prob. Stock jetting. North CA, Riding. CC Camp, Cow Mountain,

Davis Flats you get the idea.

Thanks for the time.

Could be fuel squirt adjustment needed. :)

I'm assuming this is a WR450. If so, it's the pilot jet circuit. Looking at the shop manual, the pilot circuit controls about 1/3 of the throttle from idle. In the manual there's a section on richening the circuit with the pilot fuel screw. Try that, it worked for me.

I'd adjust the pilot as well. If you're running stock and pulled the snorkel, it's probably lean. Does it idle high and then drop to lower revs? You can pull the choke and see if it runs faster. The choke is a good trick to see if it's lean on the low end (or higher if you can ride and pull it out at the same time).

What size main and needle are you running ?

Cleaned the air-filter ? :)

Age of fuel........

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