Oil in my airbox?


Recommended Posts

I have a 2005 Yamaha bruin. It has been a great bike but now im starting to have troubles.

We took it on an intense ride in Mount Magazine Arkansas. Because of the situation we had to ride it hard. After getting back we had not troubles for a month or so but suddenly I noticed it sputtering and cutting out. It wouldn’t idle worth a hoot.

I checked the exhaust, good output so it was possibly the air side. I pulled open the airbox and found about 1/4 of a quart of oil. I had just changed the oil before our trip and this oil was clean so I know it was recent. I checked the oil and it was very, very low. I poured in another 3/4 of a quart. When I started it again it spit and sputtered. I didn’t pull apart the airbox again but I’m pretty sure it spit more oil in.

I know the crankcase has a vent hose that leads to the airbox. However, I have a hard time believing its pressured oil coming through that line, at least not that much oil. My best guess is its blow-by and I need to replace the rings (re-work the top end).

That’s my guess anyway... anyone else?

Link to comment
Share on other sites

I have an old Bombardier Quest 650 that does the same thing. It's been that way since it was new though. The dealer told me it's normal after hard riding to have oil in the airbox. I just clean it out every so often and keep it full of oil.

I would try a good carb cleaning and a tune up to see if that helps it run any better.

Link to comment
Share on other sites

Sounds like a ring problem to me. I would take it to a reputable repair shop and have a compression and cylinder leak down test performed.

If you have a broken or just worn rings, these symptoms will be exhibited. " Blow by " as it is often referred to will allow oil to slide past the rings and be blown through a fresh air breather tube into the air intake box. If this hasn't been a common occurrence in the past, it certainly isn't normal.

Lynn

Link to comment
Share on other sites

I took the airbox appart yesterday and took all of the oil out, cleaned the filter. Oil level is good right now. im going to drive it around this week (ranch work) and if it gets oil in it again im going to chase it. Im hearing a million different reasons including the steep inclines we rode in Arkansas.

If it happens again any time soon ill likely just change out the piston and rings to be safe. They are too cheap and a top end re-build diesnt require much.

Link to comment
Share on other sites

  • 3 weeks later...

just an update. After cleaning out the airbox and draining the fuel from my carb I havent had any troubles. The bike is running with a little more lag than usual but im putting a new plug in it this weekend and I figure it will fix that problem. So as of right now all is good and it appears it was all just the rough ride we had taken the bike on...

Thanks for everyones input... ;)

Link to comment
Share on other sites

  • 8 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

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.