Jump to content

  • Do you own an ATV, UTV or SxS? Join our Community Forum!

    QUADCRAZY ATV Community and Forum are FREE to join! We keep our ATV, UTV, and SxS forums clean and user friendly. All first time posters in our forums will have to wait to have their content reviewed and approved. Once your first ten posts are approved, you will no longer need to go through a forum post approval process. To bypass the approval process with immediate access and a NO ADS experience in our ATV, SxS, and UTV forums, consider subsribing to a Premium Membership

91 Yamaha 350 Big Bear - Idle Issues


Recommended Posts

Hi, first time user here. My 91 Big bear will only idle on half choke. I was given the bike after it was laid up for a year or more under a car port. I have re-built the carb, replaced ignition coil, new plug, new plug cap, cleaned gas tank, fresh gas (obviously. It will start on half choke, run on half choke but when I try to take the choke off when the engine is fully warmed up after 10 mins or more of running it just starts to splutter and dies with a few little back puffs through the air air intake. Ive tried various carb adjustments but all to no avail. Ive also tried adjusting the float as it seems that the mixture is lean. Im running out of ideas.

Link to comment
Share on other sites

  • 3 weeks later...

not trying to offend your intelligence, but have you adjusted the idle screw? i just rebuilt the carb on my 93 and im still trying to get the idle set right.

also, have you checked the fuel line? i blew mine out with an air compressor, cut it in half and installed a universal fuel filter (~$4 at AutoZone) with a clear casing so its real easy to see fuel flow. i also replaced the stupid spring clamps with band clamps because they were worn out.

Link to comment
Share on other sites

the rubber manifold boot may be cracked. when running, spray some quick start around it and see if the rpm changes. if it rises, bad boot. i think maybe there is a small piece of dirt left in the carb. if you have an air compressor, blow everything out again ... i struggled with mine not quite 10 times before i got it right ...

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...