1981 GS750E With Nuts and Bolts inside

[seancanfixit]

Hi,

Long time viewer of this forum, but as of today very new member. I own a 1980 GS750EX (1981 model year). That I have had for ten years now. This bike has been full restored (engine excluded) with new powder coat frame, new paint on the engine, polished and decaled bottom engine covers, new paint...the whole nine yards. It has been a project for me for the last 10 years... a running project up until the last two years when I removed the engine for the frame resto. I just got her back on the road, all the long term without use precautions taken, got about 75k before I heard the rattle (which I thought could possibly be a loose header bolt, which is not completely uncommon) and that's just what it sounded like. On the ride home, what I can only describe is I was doing about 70k when I heard the "timk" of metal shearing and nuts and bolts inside the engine. I can only assume at this point that because the bike kept running that the cam chain is intact and that either a valve or a connecting rod has stuck and broken. I'm thinking at this point (because I can't part with my first true love) that I will open the cam cover case and proceed downward until I identify the broken piece of s***. Any advice...also If a valve has broken and damaged the cylinder wall where should I go ... big bore kit? Any advice welcome (reasonably I'm willing to spend around 1500-2000 for parts and repairs. So anything resonably will be considered.

Thanks so much to all of you out there that have shared your wisdom...your forum has saved me unreal amounts of headaches and repairs, So thank you all.

[bwringer]

My condolences and sympathy...

I have no idea what it could be either, but it sounds like you're on the right track.

I would personally remove the clutch cover, alternator cover, and valve cover to see what I could see before proceeding further. If it's not too big a pain, you might also want to remove the oil pan and take a look.

[pntrdave]

My first step would be to drain the oil and see if you get any metal shavings or other "stuff" next step would be the clutch cover, alternator cover, and valve cover. Hopefully you will find the problem there, before you tear into the engine to far.

[Cyg]

I am stumped on this one too. I gave it some thought and since the engine was running the whole time this happend. I am going too go out on a limb and suggest maybe the starter gear?? got chewed up some how. You didnt mention if you lost power or not on the trip home. If you did, you would be only running on three.

[seancanfixit]

Did lose power on the ride home. I had just replaced the clutch plates prior to the re-start. Clutch still works and I suspect that the bike would probably still fire up and run (don't want to try this however). Brand new OEM stator installed prior to this as well. Trying to think of anything else that will help. I also was having some problems on the initial and only run with a substantial power "lag" between 3000 and 7500 rpm. This was a really strange problem for this bike. Anyways, I'm goint to start tomorrow with the clutch, alternator, and oil pan covers and probably the valve cover and see where I go from there. Expect continued updates, and I really appreciate all the sympathy and help...together we'll make sure I don't have to bury her yet! Thanks all, Sean

[Carter Turk]

When you replaced the clutch plates did you reuse the clutch spring bolts?

I've reused them in the past not knowing they stretch out. I was torquing one up and realized it wasn't getting any tighter. I removed it and it looked like a supermodel.