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1990 yz 250 low end a little boggy....

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Hey guys, like title says

I finally got her running and it's just really boggy low end?

Tried idle air screw mixture adjustment.. No help... Any other ideas?

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You should check your power valve. If it is stuck open you will loose bottom end power.

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The power band feels about right... It's just a little choked during the low end of gears.... Almost like the choke is on but then the power band kicks in and it goes like snot!

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The samething happened to my 07 yz250 it was boggy on the low end.

Now the first thing i checked was the powervalve. Now i would take that side cover off to see the linkage arm on the cylinder.

First take off your pipe then take the powervalve linkage cover off then put the pipe on. Next start the bike then give it a few revs and see if the linkage goes up and down. But if it gets hanged up then i would take the clylinder off annd have a look at the powervalve.

If it gets hanged up then you may have some carbon build up. So if you do then i would take the cylinder off and take the powervalve assembly apart and clean it with carb cleaner or oven cleaner.

Also maybe goes a size up or down on your pilot jet before you mess with your powervalve. Your pilot maybe too rich or lean

thanks man and god bless!!!!

Alex

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If your floats are spec, I'd suggest dropping the pilot jet a size or two and/or raising your needle clip 1 slot up.

Bog= too much fuel

Studder/rev=too little fuel

... most of the time.

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Current jetting is stock 350 main 45 pilot needle clip 4th position from bottom. Float is adjusted to 16mm. Measuring from main jet base to top of float arm needle not compressed.

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When was the last time it was rebuilt?...and are the crank seals good? A boggy bottom is usually low compression or severely lean. The needle at the second from top is on the leaner end. I would move the clip down the needle to the third or fourth setting and see if that helps.

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It seems to hit power and when it's warmed up (riding easy for 5mins or so). Then it wants to open up... The plug appears to be darker in colour opposed to white grey ish.

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