Yamaha 600 Grizzly Rich Mixture

[JesseWeber]

I have a Yamaha grizzly 600 that smokes and seems to have a rich mixture. I can't find that it has any high speed mixture adjustment. It came with a carb which was supposed to be new. Would a new carb have such a problem? The float had to be set quite low to avoid overflowing the bowl which could suggest a poor needle valve. I don't know if that related. Anybody know what my problem is?

[Mech]

The high speed mixture is changed by moving the slide needle or changing jets. There will be an idle mixture adjustment somewhere though, perhaps underneath at the front/engine side and facing downwards.

Aftermarket carbies often need some adjusting to get them to run right.

 

[JesseWeber]

I did find the idle mixture screw. I just looked at the carb parts diagram. Looks like the slide needle would be on top under the vacuum chamber cover? How do you adjust it? 

Thanks!

[Mech]

To adjust the slide needle you take the top cover off, pull the slide up, take the needle out taking careful note of where the spacers above and below the C clip go(look carefully, they are different thickness), Then shift the C clip up or down to another groove in the needle. Putting the clip higher makes it leaner.

[Gwbarm]

If you found the air fuel mixture screw I would try adjusting that first to see if it helps, if not then move the needle , on a new carb you should not have to move the needle, this is just a suggestion , all aftermarket carbs should be close enough to factory to run properly for a while. Thats my experience .

[JesseWeber]

Thanks! I will do that today.

[Jim Denton]

Here's a good read I just came across.

https://www.webbikeworld.com/atv-carburetor-adjustment-cleaning-and-jetting/