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Oil smoke from the crankcase breather

Started by Lotsokids, September 05, 2011, 10:43:40 AM

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Lotsokids

I have pod air filters and a separate crankcase breather filter installed. My bike was idling today after about a 1/2 hour ride in warm weather, and I noticed quite a bit of oil smoke rolling out from the breather. I imagine this is not normal. Any tips? My bike has 41,000 miles.
U.S. Air Force sport bike instructor (initial cadre), 2007-2009

I'm an American living & working in Hungary

JCainFJ

Normal, my FJ did it too. That's the good news. The bad news is that this is due to poor ring sealing. Do a leak-down test to confirm this. Your FJ got hot at one time, and that will cause problems.

Sideburns

My engine too let's me know it's running hot by letting out a little smoke from the vent. I run K&N air-filters  so my cartervent is open too
I can't judge how much smoke is coming from your bike, but a little isn't something to worry about. IMHO.

pjv

I have the same set up, K&N's and a separate crankcase breather filter.
I've very recently bought the bike, not very well maintained and I had to have the carbs rebuilt right off the bat, they were jetted incorrectly and dirty. 32,000 miles. Bike runs great now.

I've noticed twice now, when stuck in traffic and/or on really hot days, i get a fair amount of smoke from the crank breather filter. About the same amount as a cigarette.

So i have a couple of q's.

1) Is the only reason this can happen poor ring sealing or could it be from over heating (potentially too lean mixture after carb rebuild). I have not done a "plug chop" yet to look at the color of the spark plugs, but i do notice a great deal of heat on my legs when not wearing leathers.

2) If this is due to poor ring sealing, how urgent is this and what are the effects of not fixing it. I'm thinking of using the bike for the summer/fall but maybe work on it over the winter (at a minimum fit new rings i suppose).

Thanks for your help folks.

Pat.

JCainFJ

 Do a leak-down test. Anything more then 10% is bad. When you take the top end off, have the valve seats re-cut, the exhaust seats can warp. Its also important to replace the valve springs, the stock springs sack out very quickly. You should be able to ride until this winter, but start gathering parts soon.

pjv

well that's a little bit depressing. bummer. Anyway, one other issue, maybe related, it's always started fine, but yesterday and this morning it took probably 4 or 5, 10 second bursts of turning over before it started, seems to run on a few cylynders after a few bursts then they all kick in, then it's fine and restarts ok. Almost like it was out of gas. is it possible that the gas evaporates out of the carbs while standing very hot? This is a new sympton, only done it twice, had it for a few weeks, no starting probs before.

yamaha fj rider

Yamaha makes a fuel additive called ring free to help loosen stuck piston rings. I have heard it works fairly well maybe try that? Cheaper than a rebuild and if it works great if not you are out $25 or $30 dollars. Hope this helps?

Kurt 
93 FJ1200
FJ 09
YZ250X I still love 2 strokes
Tenere 700
FJR1300ES

RichBaker

Quote from: pjv on July 01, 2012, 09:15:15 AM
well that's a little bit depressing. bummer. Anyway, one other issue, maybe related, it's always started fine, but yesterday and this morning it took probably 4 or 5, 10 second bursts of turning over before it started, seems to run on a few cylynders after a few bursts then they all kick in, then it's fine and restarts ok. Almost like it was out of gas. is it possible that the gas evaporates out of the carbs while standing very hot? This is a new sympton, only done it twice, had it for a few weeks, no starting probs before.

Yes.... The gas will evaporate.  I always let the pump run 'til it stops, usually have to cycle the key switch several times.... In the heat of the summer it will take one, sometimes 2 cycle before they're full... Even if she only sat for a few hours.
Rich Baker - NRA Life, AZCDL, Trail Riders of S. AZ. , AMA Life, BRC, HEAT Dirt Riders, SAMA....
Tennessee Squire
90 FJ1200, 03 WR450F ;8^P

pjv

intersting, i'll keep the pump trick in mind. But i think i foud the issue, the screw fixing the choke cable to the choke bar(?) along the top of the carbs had fallen out, so effectivley i was trying to start with no choke, hopefully that was it.
I also started another thread, re running hot, because it really is running very hot and i want to eliminate that as a cause of the smoke first. hope i'm not confusing things.