psm

I just picked up a 94 Yamaha Vmax 500. It had been sitting for a few years (with the occasional run up). Took it out a few times and noticed it bogging down when full trottle is applied. If I give it half throttle its goes good. Once accelerated at half throttle if I give it anymore it boggs down again. Ive tried all grades of gas with no noticeable difference. Any ideas?

gerard143

possible clutching issue???

dano

Possible. see a post called rich running xlt under the polaris forum, i posted a long response to start trouble shooting this problem. BUt i never thought of clutching, how many miles are on it?

psm

There are 2500 miles on it. It looks very well taken care of. I don't know much about the clutch, but to me it seems to have symptoms of fuel issues. I'll look up your post.

dnrtheil

Anything over half throttle and your carbs are using the main jets, they could be clogged.

psm

Thanks for the replies. I took the carbs off today to clean them and found one neddle jet was stuck. I poped it out and noticed some scoring on the neddle jet and cylinder wall of the carb. Any idea if the cylinder wall can be polished? I polished the neddle jet with crocus cloth but can't get into the cylinder. By the way, one of the main jets had a little bit of scum in it.

Fendrguy

If there are no gouges, Dont worry about the throttle bore.
just clean the carbs it'll be fine.

a little wear on the throttle body and carb bore is normal.

psm

Thanks Fendrguy. There are no gouges however the neddle jet does not slide freely like the other one. It gets stuck in the seated position. Is this going to be a problem?

01MXZ800

IF YOUR NEEDLE JET IS STILL STICKING AFTER YOU CLEANED IT I WOULD REPLACE IT THEY ARE CHEAP AND WOULD ELIMINATE FUTURE HEAD ACHES. AS LONG AS YOU HAVE THEM OFF REPLACE BOTH OF THEM

GOOD LUCK!

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