Quantcast
Jump to content


2006 Yamaha Bruin 350 - Running Issues

jtbaker1989

By jtbaker1989
in Yamaha ATV Forum

 Share

Recommended Posts

jtbaker1989 Newbie

jtbaker1989

Posted
Posted

Hey everyone. I have been poking around this site for awhile and I am in need of yalls assistance. I have a 06 350 bruin. It has sat in my parents garage for about 2 years and was never started. I got it home, put fresh fuel and plug in it. It would start and run great but it wouldn't idle unless choke was on. Also when you were moving and let off the throttle it would make a pop noise down by the carb area. I thought it was a dirty carb so I sprayed some carb cleaner in it and didn't help.

I removed the carb, tore it down and cleaned it. I removed the jets spraying carb cleaner and compressed air thru them. I removed the float as well and cleaned. I drilled out the plug that covers the air/fuel mixture screw. I read where the spec is two turns from fully seated. So that is where I set it at. Before I did that, I removed the screw and spring and cleaned that bore out as well.

I reassembled and now I have issues. It is very hard to start, choke or no choke, and when you do get it started, you have to hold the throttle at 3/4 way to keep it running. It will run very rough at 3/4 as well. With the air filter off, while trying to start, it is blowing a lot of fuel back out into the air filter and the plug is getting fuel fouled very bad. I removed the carb again thinking I messed something up or got the float stuck but everything looked fine. I put the carb back on the second time and it didn't change a thing. I assume its something I did since its not running like it did before I tore down the carb. Can anyone please help? Thanks a lot.

Link to comment
Share on other sites
jtbaker1989 Newbie

jtbaker1989

Posted
  • Author
Posted
check your valve clearances ... that would make it hard to start and push fuel back thru the carb ...

I was thinking about checking that but I figured if its running worse after I cleaned the carb, then I thought it was something I did. Also, with the plug removed if I hit the starter it will blow my finger off the hole.

Link to comment
Share on other sites
  • 3 months later...
  • 4 weeks later...
  • 1 year later...
canuck64 Newbie

canuck64

Posted
Posted

Almost certainly valve lash and/or burnt valve(s). My friend has one. His was doing the same thing. Adjusted the valves, found the intake valve lash at 0mm (held a bit open). Additionally, rocker not flush to the top of the valve (gap larger on one side than the other). After the valve adjustment it runs a lot better but is still lean (runs better with a bit of choke) and small pops (backfires) when backing off after high rpm. Also took the carb off. All jets clean, carb in good shape, not dirty...no issues there. It now easily runs good enough to ride...but still not quite right. I am 95+pct sure the remaining issue is slightly burnt valve as the valve-to-rocker-not-flush issue, popping, and lean condition are classic indicators of this.

They are notoriously under-powered (heavy to start with). Folks ride them and you get high rpm for extended periods. Over time this results in burnt valves (especially when the high school kids are riding the crap out of it for years).

Link to comment
Share on other sites
  • 2 months later...
Durandetto Newbie

Durandetto

Posted
Posted

I am having almost the same problems and I recently adjusted my valves and it ran great except for at full throttle. So, I pulled the carb and found some debris in the main jet. Put it back together and now I can't get it to run. If I pull the diaphragm with the needle it runs.

It's running really rich and I can't figure out why. I've pulled the carb and checked it at least 5 times and can't figure this one out. Any help would be greatly appreciated.

Sent from my SM-N920P using Tapatalk

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.

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.

×
 Share
Go to topic listing

  • Similar Forum Topics

    • semicolon
      TRX350D fuel pump problem
      By semicolon
      Hi, I am having issues with my TRX350D fuel pump.  It suddenly stopped running so I have replaced all the fuses and cleaned all the terminals.  I have fitted a new pump, fuel cut-off relay and rectifier.  Still nothing!!  The pump runs when attached to a battery.  The engine will start on the choke and the filter fills with fuel but it will  not rev and dies when the choke is closed. I have power to the relay but nothing at the pump black/white wire when cranking the engine.  Any ideas where to go from here would be very much appreciated!!
       
    • HSTAR
      1997 Yamaha big bear 350 Shift shaft issue
      By HSTAR
      Hey I have a 1997 big bear 350 4x4
      I replaced the shifter shaft and the shift arm linkage and the rod when I installed them all I was unaware that you had to line the dot on the shifter shaft with the gap on the linkage arm gap put it all back  together and rode it I can't get it to shift in the right gears  I can move the shift cam by hand and goes in different gears but with the shifter shaft in it riding I can't put it in R or N 
      Anyone know how to line up the shifter shaft and the shift cam s
       
    • BruceG
      2005 Bruin 350cc Oil pumping into airbox
      By BruceG
      Hi guys. I have a problem where the quad will start and run well for about 5 minutes and then it dies. On inspection the airbox has oil in it (quite a lot). The oil is pumping through the cylinder head breather hose. This problem first happened suddenly. I have since done the top end including, piston, gaskets, rings and valves. I have also done the carb (not that I thought that this was the problem). The compression seems normal. The only thing that I can think of, is that I did not grind the valves well enough. Anyone experienced this? If so, how did you fix it? Any other thoughts?
    • John Sinclair
      1992 yamaha big bear 350 carburator issues
      By John Sinclair
      I WANTED TO UPGRADE THE CARBURATOR ON MY 1992 BIG BEAR 350, SO I ORDERED A NEW CARB FROM EBAY.  ACCORDING TO THE WRITE-UP IT WAS A GOOD FIT FOR BIG BEARS FROM 1988 TO 1996.  WHEN I REMOVED MY ORIGINAL CARB I NOTICED THAT IT WAS DIFFERENT FROM THE NEW CARB MY CARB HAD TWO THROTTLE  CABLES THE NEW CARB ONLY HAD ONE CABLE.  HOW CAN I MAKE THIS CARB WORK ON MY TWO CABLE THROTTLE?  
    • ethie
      2012 Coleman 500 UT plug keeps fouling.
      By ethie
      Hi All
      I have a 2012 Coleman 500 Outfitter that keeps fouling out the plug within 10-15 minutes 
      not sure where to start

COMMUNITY SECTIONS

ATV FORUMS

QUADCRAZY MEMBERSHIP

Be a part of best online community of ATV riders and join thousands of people who love ATVs! Share your ATV photos, videos, ATV rides, get help with your ATV and more. Not a member?

SIGN UP TODAY

ADVERTISE WITH US

FOLLOW US ON

  • Automotive Webmaster
×
×
  • Create New...