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99 yz400f not idling, studders and dies uphill

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I have a 99 yz400, i went riding a couple days ago on the trails going up the hill, it was running beautifuly! Got to the top of the hill and started to go down the hill but everytime i pulled in the clutch it would run for a couple seconds then die. I'd start it back up and it would idle for a couple seconds then die again. Going down the hill was fine as long as i didint pull in the clutch and kept above 4000 rpm, anything lower and it would start spuddering, also when id start going i'd have to rev it to 4000 rpm before releaing the clutch or else it would stall out. It seems like it dies if it is under any load or idling. I checked the spark plug it looked fine, it may have been running slightly rich. Just wondering if anyone has any tips before i pull my carb out. Cant tell if is electrcal or a carb problem.

Thanks,

Jordan

Edited by Jordan73s

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I had a similar problem recently on my '06 WR450. Turns out that some trash had gone through the pilot jet and got lodge in the hole above, completely blocking the flow. I used carb cleaner and a fine wire (off a garbage bag tie) to clean it out.

Same thing happened to a buddy on his YZ250 last time we rode but he had trash in a different jet.

Take out the pilot jet and inspect for blockage. With the pj out, rotate the carb to where you can see through, squirt some carb cleaner (use plastic extender tube) into the pilot jet port to see if you get a strong spray through that port.

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