yz426 dies

My buddies 426 ran great all summer and when went and rode it last week, it seemed to wanna choke itself out trying to leave idle. It will rev free in neutral but when you take off in first or try to climb a hill and it puts a load on the engine, it chokes out and dies... It still runs good, just does that cutting out... iv be told the carb or valves. I was wondering if anyone has had a very similar problem and could be an easy fix before going to the dealer... Thanks!

Havent tried that one. But check the carb for damage and clean it, then see what happens..

Thanks, We have just cleaned the carb. Blew out the jets the best we could. It is still seeming to choke itself out. Any other opinions would be appricated.

How long did the bike sit unused between rides?

In the future, try and remember to cut the gas off and run it out of the carb before storing.

Especially if you know you aren't going to use it for a while.

How long did the bike sit unused between rides?

He let it sit for about 3-4 month unrode... The carb was stored dry though...

Did you drain ALL of the fuel, tank included? If the 4-month-old-gas is still in the tank it's no good and needs to be replaced with fresh gas.

Odds are that it has a varnish deposit in the pilot jet. Even if the jet looks clear, it can be partially obstructed with dried fuel deposits that will reduce the effective jet size to something way too small to run right. A #42 pilot has a .0165" orifice. A dried blob of fuel only .004" thick will turn the 42 into a 30.

Did you drain ALL of the fuel, tank included? If the 4-month-old-gas is still in the tank it's no good and needs to be replaced with fresh gas.

We did drain all fuel out of tank and when started after 4 months, fresh fuel was in the tank and lines... He has a Dr. D pipe on it, I was looking in the carb section trying to figure out what jetting it would need for the midwest riding...

So to keep track of this problem, I have checked the valves, in good spec, and then lookied at the carb again. You can see the pilot jet keeps getting clogged. Whats the best way to get this guy clean. Its been in parts cleaner for w while, when i go to blow it out, it seems to keep getting clogged. i plan to just buy a new one, but im trying to go ride tomorrow with the nice weather. Thanks everyone!

Thanks Greyracer, that clears up the cleaning the pilot yet. I will be trying these tonight and see what I come up with!!

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