Running lean, what did I damage??

[tkent02]

I'd pull the motor and take it apart indoors, in a nice dry warm shop. And put it back together with an 850 top end!

Or just find a nice tight GS 1000 engine to bolt in.

[Lorenzo]

Screws coming off... Could it possibly be, a new cam-chain has been fitted?
Measure the # of links between sprockets marks.

Here is a look of what lurks inside the cam-chain pocket.

DSC_0256.jpg

[Bortasqu]

That chain doesn't look right.

Crank ok?

[hannibal]

I finally had time and nice weather to get outside to look at the bike. I pulled off both cams. Not sure how I missed this when I took off the intake cam, but I have a broken cam chain.



The chain broke (or at least the motor stopped) with the broken link just going under the crank. See red arrow.



Not sure what this means but I'm guessing the damaged link is caught between the crank sprocket and the holder. The crank still won't turn more than few degrees back and forth. I was afraid to try to pull the chain out the intake side. In my mind, a broken timing chain usually means a piston hit a valve.

I guess it's time to start reading about cam chain replacement. Any advice?

[bobgroger]

You should first take the pan off to see what is in there, then the head. I am thinking maybe broken valve locking up motor. I hope I'm wrong but....

[jfpryde]

I'm not super well versed in these bikes yet, but I do know enough that your gonna have to tear the whole thing down before you can think about running it again. The most obvious reason is to get out any remaining metal chunks from the depths of your motor, and then to see if there are any bent valves or punctured pistons (the former being more likely). If you lucky, the pistons and valves are fine, but you wont know until you just get in there. Pull the head, visually inspect the valves, and do a leak test. Check the Piston faces and see if there is any gouges. Damage to the face of the pistons will create hot spots that will quickly lead to piston death if not addressed.

This is no longer a game of trying to identify an isolated issue, but a wholesale assessment of any possible damage done to your motor. Yes, you want to identify the reason things went astray, but that thing is coming apart one way or another. Sorry it happened, but it'll be a good learning experience!

[limeex2]

Sorry I'm late to the game, but I don't see enough info here. Could be me, but what model is this? With broken cam spkt bolts, cam chain, there will be lots more internal damage. And that's just the damage. What caused the damage? The cause must be addressed before one just throws parts at it. Without taking one more bolt out of it, you can easily see $500 in parts and gaskets. For not much more one could have a whole bike for parts, have spares, spend less time and possibly less head aches. Just my opinion....

[hannibal]

That's for the advice and encouragement. This whole experience has been a learning process. So easy to get bummed out especially when it's warming up and I hear bikes riding up and down the street.

I've come to the same conclusion about doing a thorough inspection. There's no other way to know what was affected. I'm going to pull the engine out so I can work on it inside. It's very difficult to see down into the cam chain tunnel with it mounted on the bike. I did all the prep work for removal this morning. Fortunately, I already PB blasted the exhaust header bolts and was able to get them out without breaking one (small victory but I've seen too many bad stories about those bolts). I loosened all the mounting bolts and I'm just waiting til my buddy comes by tomorrow to pull it out.

On that note, how do you guys do this? I'm not keen on laying the bike on its side and prefer to try to pull it out the right side as the manual says. It looks like I'll have to raise the motor about an inch to clear the bottom frame rail and was thinking of using a jack to raise it up, then hopefully we can just slide it out. Any advice on this?

I could go find another bike or parts bike, but I won't know the condition of that motor either so I'm planning to fix whatever I find. I do know a local guy who's looking to sell his hardtailed 78 GS750 so that's my backup plan. This is uncharted territory for me but we'll see what I find. Thanks again for all the help.