2001 Yamaha v-star clasic 650

[jonnythan]

People,
Any help here?
anyone anyone at all??

Dunno. I'd go by what the manual says.

[fshcur]

I reassebled the carbs and set the pilot screws to the manual. The bike still will not run above idel with out pulsing from very low rpms to around 1200 rpms.
I did find that by covering the intake with my hand, covering around 75% of the opening that I can get the bike to rev up without the surging problem and it idels better.
So I either have a vacuum leak or not enough fuel through the carbs.
I checked for vacuum leaks and found ZERO.
The carbs have been completly taken apart and are clean and clear in ALL passages.
Any suggestions out there?
Thanks again
fshcur

[BuzZz]

......
I did find that by covering the intake with my hand, covering around 75% of the opening that I can get the bike to rev up without the surging problem and it idels better........
fshcur

That trick is proof that your carbs are not delivering enough fuel. By reducing the amount of air in the mixture, the fuel-to-air ratio is brought back closer to optimum as proved by the improved performance.

You can only assume that the carb(s?) are not flowing enough fuel into the intake air stream. Most probably because of build-up inside the tiny passages through the jets. Possibly a small air leak (AKA-vacuum leak) internal to the carb is causing the jet circuits to see less vacuum and therefore pass less fuel...... but really, at a wild guess, it's probably the jets. (that last statement pretty much assures it's not the jets but something else )

BTW, the bike only runs better with restricted air intake because it is sitting still in neutral, if there was any load on it, like pushing you and itself down the road, it would be severely lean, run very hot and have poor performance. Then it will blow up. So don't do that.

Not that I think that you would do that, but just in case someone else reading this might decide to try it on their bike someday.

[fshcur]

BuzZz,
Thanks for your insite.
I was checking for vacuum leaks again and found that the front carb was leaking at the gasket going into the intake. I replaced both of them and the bike would run and I had to readjust the idel and re-sysnc the carbs.
It now runs as good as the day I bought it.
I will take it in to a shop and have them double check everything prior to riding very far.
I did take it for a short ride and then checked the spark plugs and they look normal, light gray color.
Be safe out there people and enjoy the Summer.
Thanks for all your help.

[BuzZz]

Good to hear it's running right.