White Smoke & Overheating

[Guest]

On returning from a 300 mile ride this weekend, I got stuck in traffic with my 16,000 mile 1982 GS850L. It has been running like a new bike with no real issues to speak of. While sitting, or creeping along in stop and go traffic, the guy behind me said he saw white smoke coming out of both my exhaust pipes. On acceleration, the bike was also 'pinging' or detonating, I guess from over heating. Once I started moving again, the bike ran great, after I guess it cooled down a bit. When I got home, I was about 1/3 quart low in oil.
I was planning on taking the engine apart this winter to replace a tiny leak in the base gasket. My question is, if I'm burning oil out the exhaust, through (I guess) the combustion chamber, am I also looking to replace rings and/or valve guide seals, as well as getting the cylinders re-honed? Would this be normal for a bike with only 16,000 miles? My buddie's bike was also over heating and bucking, but no smoke, so that's my concern. I was going to start by doing a compression check on all the cylinders, both dry and wet to see the results.
Thanks.

[Nessism]

First all, it's downright foolish to NOT change the valve stem seals if you are tearing down the top end. The seals are rubber and subject to aging and decay as all 30 year old rubber parts are. The rings are a more difficult decision; it's an extra $150 on top of the gasket cost, which isn't too bad, but not strictly necessary either. I'd let the compression test decide this one.

As an aside, synthetic oil, such as Rotella Synthetic, is a good hedge against extreme temperature problems like you experienced. The engine will get just as hot, but synthetic oil clings to the engine parts better in those instances and doesn't flash off and evaporate like dino oil.

Good luck

[BassCliff]

Hi,

Is the bike running lean at idle? Have you adjusted the idle mixture screws using the "highest idle" method? What do the plugs look like after it's been idling for a few minutes?


Thank you for your indulgence,

BassCliff

[Rocketman]

The bike is running better than ever, and I haven't touched the idle mixture screws or looked at the plugs since the last time the carbs were rebuilt. I figured why tamper with it, if its running so great. This is a new occurence, and the bike has not been touched or adjusted by anybody recently.

[Nessism]

Is the bike stock, or modified in any way? Are the plugs a nice tan color, or white? If the plugs are white, it wouldn't hurt to richen it a smig.

[Rocketman]

100% bone stock except for the back rest and windshield. I'll check the plugs next time a get a few minutes.

[SqDancerLynn1]

Personally I wouldn't worry about it.. My 79gs850 had some (since replaced) bad intake boots. Would ping real bad and blow a cloud of smoke out the pipes when accelerating. That was 20k miles ago No problems.. The rings should be OK. Taking it apart I would remove the pistons and soak the pistons with the rings in some carb cleaner- at the least use some spray cleaner on the rings to remove the carbon

[bccap]

As an aside, synthetic oil, such as Rotella Synthetic, is a good hedge against extreme temperature problems like you experienced. The engine will get just as hot, but synthetic oil clings to the engine parts better in those instances and doesn't flash off and evaporate like dino oil.

I have been wondering about synthetic oils for a while now. I'm a firm believer in using the best oil product available. But who is right ? I've heard both sides of the story. Below is a copy of last months Practical Sportbike's question and answer. Any thoughts or experience with Synthetics ?

[Nessism]

I don't want to turn this into yet another oil thread since we already have too many of those. If you do some research on the net, and spend some time on the Bob Is The Oil Guy forum, you will realize that synthetic oil is good stuff, but greatly misunderstood (as is regular oil as well). Bottom line is synthetic oil has some positive characteristics, including it does not thin out as much with high temperature, so it protects better at melt down temps. It does not reduce friction as some people think. If you are worried about clutch slippage then get a MA certified synthetic like Rotella synthetic. The long life of synthetic helps mitigate the high cost, to a point, since you can run the stuff longer before it's used up. In normal usage where the engine isn't getting to killer hot temps, and you are able to replace the oil at normal service intervals, there is no real advantage to synthetic.

[BassCliff]

Hi,

I have been wondering about synthetic oils for a while now. I'm a firm believer in using the best oil product available. But who is right ? I've heard both sides of the story. Below is a copy of last months Practical Sportbike's question and answer. Any thoughts or experience with Synthetics ?

From your "mega-welcome":

A Few Words About Oil I'll tell you what I use and why. I use Rotella-T Heavy Duty 15w40 oil. It is actually diesel engine oil and contains more anti-wear additives, phosphorous and zinc, that these older high-revving engines love. At about $12 a gallon from Wal-Mart, it's less than half the price of many motorcycle-specific oils, and is the best "bang for your buck" value. The synthetic Rotella-T is just fine too, it won't hurt your clutch. If you like, continue reading the links below for everything you ever wanted to know about oil but were afraid to ask.
Here's a great article on motorcycle-specific oil in general.
Here's a 2nd great article, also on motorcycle-specific oil.
Sport Rider Magazine ran a feature awhile back on motorcycle oils as well, and included some testing with detailed results provided. Well worth the read!
Sport Rider "Oil's Well That Ends Well" Part 1
Sport Rider "Oil's Well That Ends Well" Part 2
Richard Wildman (of Richard's Corvair) explains in layman's terms all about grades, viscosity, shear, additives, specs, etc.
Richard's Corvair - Selection of the Right Motor Oil for the Corvair and Other Engines

And, of course, Bob the Oil Guy is a fountain of information.




Thank you for your indulgence,


BassCliff

[bccap]

Thankyou Bikecliff and Nessism, as per your posts I think I will stick with dino oil. My research on the net had produced some somewhat controversial results. My apologies to Rocketman for temporarily highjacking your thread.

[850 Combat]

Some Japanese air cooled fours have been known to warp cylinder blocks from getting hot, and loose a bit of compression from it, at least according to an old Joe Minton article on the Yamaha FJ1100.

personally, I wouldn't worry about it. Might as well do valve seals if the head is off, but that would be about it. Keep an eye on the oil level to see if you have a trend going, also change the oil now, because you may have overheated it.

I stuck a piston on a fresh Brit bike motor from being in bad traffic for a long time, then getting cought in a left turn lane where the light wouldn't change. I thought I would have piston rattle after, but it seems fine.

[Rocketman]

Thanks for all the advice. I think this winter while I'm replacing the base gasket, I'll address some of the other issues, without doing a total overhjaul. Just freshen things up a bit.

[BadBillyB]

On returning from a 300 mile ride this weekend, I got stuck in traffic with my 16,000 mile 1982 GS850L. It has been running like a new bike with no real issues to speak of. While sitting, or creeping along in stop and go traffic, the guy behind me said he saw white smoke coming out of both my exhaust pipes. On acceleration, the bike was also 'pinging' or detonating, I guess from over heating. Once I started moving again, the bike ran great, after I guess it cooled down a bit. When I got home, I was about 1/3 quart low in oil.

Before doing anything else, I would drain some of the fuel out of the tank into a glass jar and see if there is any water in it. Water produces white smoke and also doesn't burn very well (pinging)......Billy

[Nessism]

I'm pretty sure the smoke problem relates to the oil reaching the flash point and vaporizing. It's not due to water in the gas or anything else. There have been a couple of different threads here over the years on this exact same pattern repeats. Once the engine cools off everything gets back to normal, and thanks to the robust nature of the GS engines, there typically aren't any lasting effects. So again, synthetic oil will reduce this tendency. It's worth the extra cost in just these instances in my opinion.