Oil/gas coming from breather tube

I have a 1980 maxim xj650. It's a real piece of crap. I'm trying to change that. When I got it...handymans special doesn't quite fit the bill. Finally have it running...but when I changed the oil and filter. Now when I start it, oil and gas will leak from breather tube...quarts worth. I have no idea why. Has anyone else experienced this problem or know a possible solution?

 

Leaking petrol tap and sump has overfilled with petrol. Floats also need attention. Do not start bike until sorted.

 

Deleted

 

It will happen when I have just started it, or while I'm riding it down the road. My driveway is an oil stained mess.

 

Oh, the petcock? When I took tank off, with petcock positioned to "off" it didn't leak any gas. Could a leaking petcock still be the issue?

 

Nope. The petcock can be an "enabler" but it sounds like yours is working as it should.

You have one or more stuck or mis-adjusted floats and the carbs are dumping fuel into the crankcase.

STOP RIDING IT or even running the motor until you fix it; you're running on gas-diluted oil.

 

And that's what makes the oil/gas mixture dump out of breather tube? Guy at work said my piston rings could be bad, and that seems like a major project. I most recently took the carbs apart cleaned them and bench synced them via the paper clip method I found on here.

Furthermore, if that is the reason...I'd need to take carbs off and apart and do a better job of cleaning them nd adjust floats, and after new oil could that possible solve issue?

I'm sure there's a float adjustment tutorial on here somewhere I just have to find it.

If I change oil, do I need a new oil filter as well?

 

Yep. Oil/gas is coming out of the breather because the crankcase is becoming overfilled with the mix. BAD FOR MOTOR.

Yes, you do. Float levels: http://www.xj4ever.com/setting%20fuel%20levels.pdf You're also going to want to pull the pilot screws, replace their o-rings; remove the emulsion tubes and throughly clean them inside and out, and ensure your enrichment tubes and passages are all free and clear.

I would replace the oil filter too, once the problem is solved.

Remember you'll need to get your valve clearances in spec before you can properly vacuum sync the carbs.

If you're worried about your rings, once the valves are in spec do a compression test. Good idea anyway.

 

According to the article, I'd need new floats? They looked to be in good condition. The gaskets need replaced for sure. But, do I need to sync the carbs every time I take them off?

 

Doubtful you need new floats. The floats themselves rarely need replacing, you may have mis-read.

New float VALVES, possibly. Valve needles, possibly seats.

You don't necessarily need to sync the carbs every time you take them off; but until the floats have been properly set and the carbs thoroughly serviced and bench sync'ed, then the final sync is a ways off. Generally speaking, once everything has been done correctly, the vac sync and mixture tuning are the final steps. Once they're ALL DONE then you won't be taking them off again for another 10K miles or so unless there are issues.

The final vac sync is quite precise; and often the R&R process will disturb it slightly. However, there are usually other maintenance items accompanying routine carb removal and in those cases, a sync touch-up is usually needed; as it often is after a valve clearance adjustment.

So the answer to that question is no but often yes, depending on the circumstances.

And you can't simply ignore your valve clearances.

 

I had same problem with gas in the crank and when testing the petcock it was 100%, it was the needle seats in the carbs that were toast. new needles and seats and its like new again. No amount of carb cleaner will ever fix that.

 

also, if the o rings around the seats are bad, gas will leak even with properly working floats/needles/seats.

 

Only the Mikunis have those o-rings. (Although I believe the Hitachis have a washer of some sort.)

 

Hitachis do indeed have a fiber washer that fits on the shoulder of the float needle seat. They will come with the repair kit.