Weird engine noise, tapping. 1982 GS650GL

[William Groebe]

I recently rebuilt the lower end of my 1982 GS650GL.

I had a bad bearing on my crankshaft which wore down to nothing and ripped up the crankshaft in the process, so I had to buy a replacement crankshaft and a set of all new crankshaft and rod bearings. I put it all back together and it runs. Yay.

But after a bit of riding I noticed some tapping sounds coming from the front/right-ish area of the engine and after about a ten minute ride down the freeway I started to lose power and the tapping got louder.

I got the bike home and checked the valve clearances. One was under .03mm so I replaced a shim and now it's at .06mm clearance, so all my valves are within spec of .03mm-.08mm. I took the bike back on the road, but the tapping started up again right away.

Here's a video of what the tapping sounds like. Any ideas?

https://www.youtube.com/watch?v=iyL08O2D4L8

This sound is similar to the one I heard when I blew a bearing. I hope that's not what's happening this time. I spent a long time trying to fix that and I'd like to not have to open up the crankcase again.

Thanks

[Sand_fiend]

Sounds like a rod to me.. Sorry..

[tom203]

Maybe the camchain jumped on sprockets and a valve is bumping a piston- this would explain lost of power and tapping. Are you sure that you got tensioner reinstalled and reset correctly? Doublecheck camshaft to crank timing and hope for something simple.

[barnbiketom]

Sounds like a rod to me.. Sorry..

+1 on a rod......

[eil]

I followed your previous thread(s) rebuilding that engine. I don't have anything to offer except my condolences if you have to tear into that lower end yet again.

[ukjules]

Perghaps a dumb ass of an answer BUT:
It is not needing the exhaust gaskets being tightened is it ?

Tis odd as it sounds great ticking over and tick over it does well !
Babng the throttle and then a odd rasping sound ?
The perect tickover gets me as that means carbs, timing must be close ? (diso****ing timing chain?

Ill go back to my burrow ................. and be silent but it can be the simplest of things soemtimes ...

[eil]

It would be a heck of a road trip, but here's a $400 engine in assumed working order: http://www.thegsresources.com/_forum...650GZ-for-sale

[William Groebe]

Yeah, I'm assuming it's a bearing as well. It's doing the same exact thing it did before I blew it the last time. Thought I'd be in the clear with an entire set of new bearings, but nooooooooo. I must have done something wrong. I took plastigage measurements and everything was in spec. Maybe I didn't lube them up with enough oil when I put it back together.

Oh well. Tonight I'll take off the head and cylinder and pull on each piston to see if there's any play. If so, I'm going to pull her open yet again. No big deal at this point. I'm a pro.
wink wink. sarcasm. yay

[tkent02]

Yeah, I'm assuming it's a bearing as well. It's doing the same exact thing it did before I blew it the last time. Thought I'd be in the clear with an entire set of new bearings, but nooooooooo.

I'm thinking the bearing is failing for the same reason the last one did, lack of oil. Did you ensure all of the passages everywhere in the bottom end were not blocked? Yours would not be the first engine (or second) taken down by an errant blob of RTV.

[William Groebe]

You are probably right, tkent02. I didn't get a chance to check anything tonight. Looks like I won't have time til Wednesday to take it apart. When I had her open I didn't blow out all the passages with compressed air. I should have, but i didn't. If it's the same bearing that blew then I know where the problem is. We'll see soon enough. Thanks for all the help.

You are all good people. Love the support I get on this site. I'm going to start donating to the GSR. You guys are too awesome and this forum is too amazing for me to keep on freeloading.

Thanks again.

[60ratrod]

Will, if it turns out to be the same issue, I would take the case, head, and cylinders to a machine shop and have them clean it and go through all the passages. I believe this would be the best money spent to prevent other issues in the future.

[tkent02]

You can certainly do all of that yourself. It's not like there's very many passages to clean.

[William Groebe]

I had time to pull things apart today and yes, the #4 piston is loose, so the bearing is worn down again. It's not as loose as the last time so I hope the crankshaft is still good and I can just replace the bearing and clean out the oil passages.

Good news is that taking the engine apart is pretty fast for me now. In less than 2 hours I've got the engine off the bike and up on my workbench. I'll keep you all posted.

Thanks for the suggestion, 60ratrod. I may take my engine to a machine shop. We'll see. It depends on how it goes when I blow air through the passages. Want to see what I can see first.

[60ratrod]

I suggested taking it to a machine shop to have it cleaned because they know how to get those passages really clean. If you go that route, make sure they are a good reputable place. And damn man, this really has been a trial in patience for you. At least you post in depth informational posts. Your first tear down is what i used with the service manual.

[tom203]

"Good news is that taking the engine apart is pretty fast for me now. In less than 2 hours I've got the engine off the bike and up on my workbench. "

After all the work that you've done, I'd probably have other ideas than the workbench. Carry on !