mily oil leaking from the spark plugs....

[Nothinghead]

So, i started up my "new" 79 XS11F when i got it, and the thing smoked white off the cylinders and head once it warmed up, and wouldn't go away. the engine was filthy, so i assumed that was just all that gunk (mostly oil) burning off. then after about 20 minutes or so of running at idle, milky oil was leaking out of the numbers 1 and 4 spark plugs, so i shut it down. i have since decided to tear the whole thing apart and do a full restore to the bike, but what may have been causing that oil to be milky, and wy/how could it leak form the spark plugs?
Thanks in advance.

[natemoen]

Well I would say the how would be that the plugs were not tightened down adequately. As to the what and the why I cannot say.

[XS1100_OEM4ME]

Plugs

First, I would clean the motor, auto de-greaser will work well. Pull the plugs check for condition (color chart/ware chart). Next, replace with correct NGK (IMHO), change oil with 10w40 "motorcycle oil", check compression, if good or close you may not need a rebuild. I would "not" let it idle for 20 min. ever, it is air cooled (needs to be moving not to over heat) When the bike is road safe, IE. brakes and all working, take it out for a ride with new oil and plugs for a 100 mile or so. Check plugs for color/foul and that will tell the story of motor condition.

[TopCatGr58]

Hey Nothinghead,

Since it's new to you, you may not know much about what the PO did to it, like perhaps not tightening the plugs adequately! White milky oil is usually a sign of water contamination...usually thru condensation....from an engine that has sat, and then is started, but not allowed to develop full normal operating temps, and then let cool down, repeat. This prevents the water from being vaporized and blown out of the warm engine, it condenses and gets mixed in with the oil!

As stated, check compression....if good...stock new is 142 +/- 12 psi at sea level IIRC. It may register a bit lower due to both mileage, as well as sitting=stuck rings, a little rust in the cylinders, etc.! If it's near 110 or more and fairly even....within 10% of each other, then you would not want/need to tear it down. Just get it reconditioned, proper new oil/filter, cleaned/synched carbs, etc., and then put several hundred miles on the engine to help reseat the rings, and then retest the comps.

Regrettably, you can't get standard oversize pistons for these machines anymore...Yamaha doesn't support them, you're only options are the big bore kits from Wiseco...as the cheapest and they are still $400.00+ for set with rings, pins, gasket, plus boring fees, etc.!!!

These machines are quite strong, and many have put close to or over 100K miles on them...so don't be too hasty to tear into the top end!

T.C.

[b.walker5]

TC is right, "white" oil is usually a sign of moisture in the oil, and as long as your compression is within cooee of spec you shouldnt need to tear it apart.

I May be wrong, and I cant remember if it was here, the Uk site, or the Auz site, but someone was talking recently about a possible alternative supply of pistons. IIRC there was a minor issue with skirt height (1 to 2mm) but I imagine 5 minutes in a lathe would be enough to fix it without affecting the balance to severely.

[XS1100_OEM4ME]

Water

Milkey leak should be caused by two things. First water in motor, all the more reason to change oil before running again, 2nd, leaking around plugs, not tightened right or poss, but not likely, bad plugs. On a "dry" day after the oil change, warm up the motor, 5 min at idle will do. Take out the plugs and air dry the cyls. an hour will do If you have compressed air, that wont hurt ether, as long as the motor is cleaned and nothing can blow into the cyls. after letting O2 evap. squirt about a 1/2 OZ of motorcycle oil into each cyl and craknk it over a few times, follow the rest of my rec. and I will bet your motor is OK, hope for the best for you and your bike.

[CatatonicBug]

change oil with 10w40 "motorcycle oil

I agree with all the other stuff, except for this one. This time of year, 20W50 is usually best, and motorcycle oil is a waste of money. Regular dino automotive oil (without the friction modifiers) works just fine, at 3/4 of the price. Once the weather turns colder, you can switch it out for 10w30, and ride all winter.

[Nothinghead]

ride all winter... wouldn't that be nice. it gets to -35 up here in downeast maine, so i don't know about that. but thank you for the info.

[CatatonicBug]

ride all winter... wouldn't that be nice. it gets to -35 up here in downeast maine, so i don't know about that. but thank you for the info.

LOL.. OK, maybe not ALL winter.

[mack]

Valve guide oil seals

may want to look at these and replace if you wind up taking the head off. Not enough info at this point , but you have condensation in the chambers for sure. Follow the advice by the pro's and re-evaluate after that.

[Nothinghead]

wow, so it would appear i was a bit hasty in tearing down the engine. my thought was that the gaskets were going and leaking minuscule amounts of oil, so i ordered up a new gasket set, and have the cylinders off it now, waiting to replace the gaskets. i planed on painting and restoring the bike anyway, i just saw this as an opportunity to actually do it. hmm. well, thank you all for the advice. i am happy to see that this is not a forum where opinions seem more important than helping each other, as so many other forums i have been in turn out to be.

[XS1100_OEM4ME]

You might check

Just a few things you might check now that you have her down. Take a close look a 2nd gear, they can wear and slip out under load, there is info on here how to fix if you need to. I am guessing you will be replacing bearings, rings and seals, you will also want to check spec on all springs, valve (an do the seals, prob came with you gasket set, debur your valve stems at the top if ness or you can kill your guilds), clutch springs and also friction plates in clutch. If you run into any ? the guys on here know these bikes well. As to the oil, 20w50 is fine for hot weather (though out of yamaha spec) IMHO the price of a gal. of good motorcyle oil -V- the price of a good auto oil is about enough money to buy baconateor combo at Wendys, so you make that call, I am gussing you are makin a large investment in the rebuild, IMHO eat one lunch at home and call it cheap insurance.