83 gl1100 stop running and won't start

[GLnewbie]

Hello everyone. Looking for some insight. I was driving to work when the bike lost rpm and died. Immediately started back up went 50 ft and died again and won't start. It seems it is smoking from timing belt case. If anyone has any ideas where to start that would be great. I had a full tank of gas and all fluids are full on the bike.

[DenverWinger]

Smoke from the timing cover?

Maybe you seized a timing belt idler bearing. But seems that would have made an awful lot of noise, and hard to say if there'd be enough drag on the belt to stall the engine going down the road.

[OldguyGlen]

So many questions. Does it crank ok, but not start? Is the smoke heavy enough to identify source, might it be coolant? Plugs wet or dry after start attempt? Spark? Shot of starter fluid to see if it's fuel problem? Need more info.

[GLnewbie]

It attempts to turn over and sounds healthy. Smoke coming from back side of timing belt case left side of the bike. No fluid is leaking as of now. Haven't had a chance to check the spark plug as it just happened and I'm at work with it.

[LAB3]

Any idea what the smoke smells like? Rubber? Oil? Gas? Anti-freeze? Electrical? Either way it goes I'd be very wary about running the bike any further until you sort it out. If it turns out to be a timing belt issue and it lets loose you can count on a major repair or replacement of the engine.

[GLnewbie]

Finally had a chance to take a look and it's not good. Cam shift snapped.

[LAB3]

You MIGHT not be too bad off depending on the reason the camshaft snapped. If the belt is in tact it more than likely didn't go out of time and it would make sense that the valves would come to rest closed and not hitting the pistons. I'm not sure what would make a camshaft do that other than a timing belt failure but maybe someone else could chime in on that. Start looking around on eBay for a replacement camshaft, you might not be too bad off on this one.

[GLnewbie]

Both belts were still together and both looked pretty good. I just got the bike back to my shop. I'm going to attempt a compression test once I figure out how I will do it. Worse comes to worse I'll just have to strip it down to make sure the valves aren't bent.

[Rambozo]

One thing that can snap a cam is a clogged oil passage to the cam bearings. Then the cam will lock up and bingo. If that is the case you might need to replace the head. And of course be sure the oil passage is open, or the new one will follow the old. I have seen this on other engines from not having the head gasket in correct, so it blocked the oil passage.

[GLnewbie]

Update removed the head in question about a gallon of coolant dumped out and both cylinders had hit the valves. Camshaft also had taken chunks out of the head.

[Rambozo]

How do the pistons look? Any damage out near the ring lands?

[GLnewbie]

Haven't fully pulled them out but here is pictures. Top photo you can see the two dents on the lower half

[Rambozo]

It's close, but if you're lucky it hasn't seized the rings in their grooves. I would turn the engine over and check the cylinder wall in that area for any abnormal scuffing or scoring. A little oil placed on the wall should be scraped clean by the rings. Then make a blanking plate to go over the top of the cylinder to allow a leakdown test. If that passes, and the sealing surface is flat, pop on a new head and you should be good to go.