Quantcast
Jump to content

  • Join Today, It's Simple and FREE!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

Matt Taylor

1990 yamaha big bear 350

Recommended Posts

I have a 1990 big bear 350. It just started dying and back firing while being rode. Also tries to die out while riding. If I down shift then shift back up it runs ok for a few minutes. I've read a few things that the fuel could be to lean and needs adjusted. My buddy said timing chain. Any help would be appreciated thank you

Share this post


Link to post
Share on other sites


Could be water in the float bowl,or a piece of floater dirt.loosen and remove bowl drain screw,turn on fuel and let some run out,it may wash it out.

Share this post


Link to post
Share on other sites

99% chance it’s a fuel delivery problem. 

Share this post


Link to post
Share on other sites

Thanks out there, I’ve also got a 1990 Big Bear 350 and I’m having the same problem. Sometimes it runs perfect but, then intermittently misses and farts. I don’t think the Big Bear can change timing. It’s all in the Black Box. So I’m going to drain my tank, flush it and clean the petcock. Then change fuel filter and clean float bowl. 👍🏻

  • Like 1

Share this post


Link to post
Share on other sites

That’s a great way to get after it.  Make sure you clean the rest of the carburetor and not just the float bowl.  Throw a new spark plug in as well. Count the turns you unscrewed the air fuel screw out of the carburetor as well. This way you put it back exactly where you took it out.  Should be about 2-1/4 ish turns.   Good luck. 

  • Like 1

Share this post


Link to post
Share on other sites


also if you have an aftermarket exhaust it can play havoc on some machines without some fine tuning.

  • Thanks 1

Share this post


Link to post
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.

Guest
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.


  • Similar Topics

    • By Belmontie
      Hi bought this quad with a few leaks and other issues which thanks to excellent advice from these forums I thought I’d sorted them till I washed it down and found oil underneath. 
      It is coming from the seal around the gear changer pedal as it looks like someone has banged the housing flat on one side. Knowing how easily aluminium is broken I don’t wanna risk tapping it back into shape. Would a new seal fit or would the distortion of the housing render it useless.
      thanks in advance 
    • By JacobSlabach
      recently picked up some project bikes off CL for cheap.  got a honda fourtrax (the ancient 4x4 kind with the straight axle in the front as well as the rear and a back-up kick-start)  plastics are crap, but my goal is to get running like a champ and patch the plastics up and sell to one of my many friends that want a reliable 4x4 for dirt cheap and doesnt care what it looks like.
      so the former owner says it needs carb rebuilt, but its sat for 3+ years since so who knows.  things I see:  carb is missing (he gave me a box of parts along with the bike), engine turns over and feels good with kick-start, brakes need work, battery missing (That always puts me off, cause then I know most likely someone's been tampering with the electrical.
    • By Alex91
      I have a 92 suzuki king quad that seems to be getting way to much fuel in my spark plug hole as I took out plug cranked it over and covered myself in fuel I cleaned carb and fuel filter and fuel pump all seems fine any other ideas
    • By joseph
      my atv will start right up will idle fine soon as i try to throttle up engine dies,i have changed gas,new fuel pump and lines great compression 188 lbs.new coil new spark plug adjusted valves dont know what to do also rebuilt carb,any help wanted
    • By Scott Matthews
      Just picked up a 1989 Big Bear 350 for $250 CAD. Bike was running but lost crank and spark. They've installed a new coil, a couple relays, and installed a Ford starter solenoid in place of the original. Now it cranks but has no spark so they sold it to me. Does anyone have a wiring diagram for this bike so I can test some wiring. Also any ideas as to direction to head would be nice. Lots of things have been hacked together so I know it probably wont be to easy. The ignition switch was replaced with a toggle switch, I already mentioned the Ford solenoid which 1 of the small wires was not re-installed, and a diode or something was removed from the oil temp sensor wire. I'm sure I will find more so a diagram would be amazing.
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...