Oil coming out of airbox.

[BobBaldy]

My bike started using about 1 quart every 100 miles and I finally found where it was going. I have oil coming out of the airbox. Before I open up the crankcase breather and try to clean things is there anything else I need to know?

This is Sunday and I don't get off work until Tuesday so hopefully in the next 3 days I'll get some good advice like I always do on this site.

I'll post the fix with pics to this thread for posterity.

[cajun31]

few things

got to ask the obvious question.... how much oil are you putting in the bike? I know probably a stupid question and are you changing the oil or adding oil with the bike on the center stand or side stand? Asking these questions because I don't know how long you have had the bike or how familiar you are with it.

Ok... stupid (I hope) questions out of the way...

Second question...... How many original miles are on the bike? How long have you had it and do you do regular periodic maintenance on the bike?


Third point or question... do you have a way to check the compression on the bike... the reason I ask is you may be experiencing excessive blowback from worn rings. If that is occurring then the back pressure is building up in the crankcase and is probably venting through that breather hose to your airbox.

[natemoen]

got to ask the obvious question.... how much oil are you putting in the bike? I know probably a stupid question and are you changing the oil or adding oil with the bike on the center stand or side stand?

He askes these questions because about the only reasons for oil blowing up into the airbox is when the crank case is over filled. That happens 2 ways usually, checking/filling the oil level using the oil level window when on the sidestand, OR if the carbs overflow and dump gas into the cylinders and the gas fills the crank case.

[BobBaldy]

I put 5 quarts inwhen I did the oil change on the side stand because the center stand is missing. I then looked in the fill hole to see where the level was because the oil level window is all clouded over and you can't see anything.

there is about 55,000 miles on the bike and I've had it running for two years now. I put 500 miles on it last year and about 250 this year. I do my oil changes at the start of the season and every 3000 miles.

I use to have a compression checker but I think it's in the basement at my ex wife's house so I won't be getting that anytime soon. I guess I need to buy a new one. I'm curious as to what the compression is anyway so I will get on this.

there does not appear to be any gas getting in the crankcase


thanks for the quick replys. I wasn't going to check it until tomorrow evening but I got an email saying someone replied to the thread already. I was pleasantly surprised.

[BobBaldy]

I forgot to add that when I checked the level through the fill hole I was on the bike and holding it up right.

[IanDMacDonald]

Five quarts is too much. Excessive oil is probs ur issue.

[cajun31]

The problem

is that you have too much oil in the bike. You stated that you put 5 quarts in... the specs from the manual with oil and filter change is 3.7 U.S Quarts. If you don't change the filter then it is only 3.2 quarts. You need go ahead and drain all the oil out and replace the filter and oil and follow these specs. I would think your compression is fine but it wouldn't hurt to know for sure.

[BobBaldy]

Crap. I went by memory and thought it was five quarts.

I'll do the oil change and eyeball the level again.

Thanks guys.

[BA80]

5 quarts is too much oil. It only needs about 3.5 quarts, mine with an oil cooler only takes a little over 4 quarts.

If you have a stock airbox and the crank case breather system is intact inside it the oil should be shooting into the bells of the carbs and you'll have a lot of smoke from the exhaust.

Fix that SIGHT GLASS

[BobBaldy]

I've got no smoke coming out of the exhaust just oil dripping out the airbox.

I'll change the oil and filter Tuesday because I work 12 hour shifts. I'll also borrow a compression checker from O'Reilly's and post the results in case anyone is curious

[BA80]

One other question Bob. If you can't see the level in the sight glass how do you know when it's a quart low?

[BobBaldy]

When I look in the fill hole with a flashlight there is a hump in the case. At 5 quarts it was about an inch above the hump so when I could see the top of the hump I added a quart.

[cajun31]

You might want

to just drain about two quarts out then put about a quart of marvel mystery oil in and run it until it get to operating temperature. Don't rev it hard while you do this and don't ride it. I swear by this stuff and it is good at breaking down deposits inside the engine... might even clean the looking glass.

I have also looked at threads where folks have substituted seafoam and do the same process.

what I would do ... for sure is see if you can get the gasket for that crankcase cover so that you can remove it and clean it good. Is the glass just clouded or is it just black with build up. The reason I ask is you can still get those new and if it needs to be replaced you could pick one of those up too before removing the cover. one source for one http://www.mrcycles.com/oemparts/a/y...rankcase-cover

Also you might want to look a few threads down from this one and grab a copy of that service manual off of catatonic bugs web site.

What is the reason for the center stand missing? done some custom mods to the bike? Would like to see of picture of it.

Running that much oil is not good for your seals either .... hopefully no damage was done to them. Probably not if the oil was making it to your airbox.

[BA80]

You don't need a gasket, Yamabond or Threebond is all I ever use on the covers and case. A NEW sight glass is only $9 from Mike's XS as in the link I posted.

[dolphans1]

I know its a bit unrelated, but still informative, but with Nascars, running at high speeds the entire day, oil causes friction, so there cars only run about a single quart of oil through their crankcase .

I heard this a long time ago (years), that they run something like 16 quarts, however, their oil runs through a cooler/pump, and there's only a single quart of oil running through that engine constantly. (hey is that really a stock car?)

I also heard a true story, where this guy took his car to a quick lube change, and they accidentally put 90 weight gear lube in a new car crankcase, and the car only went a few miles down the road and the rods began knocking.

That much oil can cause a lot of excess heat and back pressure.

Oil, like water can't be compressed.