81 GS1100e..vibration

[trevor]

Hey guys,
So this is the bike I bought in October...1981 gs1100e 34,000kms (20,000miles)When I bought the bike it was smoking and had my mechanic (yes I am not mechanically inclined but you guys knew that lol) put in new rings and it is fine now.
Ever since I got the bike though I have noticed it vibrates way more than my other bikes. The carbs have been synched and the valves are adjusted to spec too. The bike runs great. fires right up and idles nice but it does sound a little louder than my 83 1100e.
The bike has stock exhaust so I thought it would be smoother than my 83 that has a 4-1 on it. But no..man after 15 min of riding my hands are falling asleep. Pegs vibrate and my wife noticed it to.
The bike seems to perform fine and I don't notice much of a difference in performance from my 83...but the vibration is driving me crazy!!
I'm really hoping im not going to here the words "twisted crank"
Thanks for your help guys and please keep in mind my limitations.

And i have gone over every nut and bolt on the engine and mounts.
Maybe this is the nature of the 80-81 1100E??

[blowerbike]

i would have checked the crank with an index rod when doing the rings(pistons off).
you could have a main failing/failed but you could have an alt. rotor/crank taper damage.
what i mean is it could have spun and been replaced with red loctite to hold it in place for the time being.
pulling the rotor would tell the tale...anything else means a major disassemble job.

[azr]

i would have checked the crank with an index rod when doing the rings(pistons off).
you could have a main failing/failed but you could have an alt. rotor/crank taper damage.
what i mean is it could have spun and been replaced with red loctite to hold it in place for the time being.
pulling the rotor would tell the tale...anything else means a major disassemble job.

oohhhhhhhhhhhhhhhh...........sometimes it's just better not to ask

[trevor]

Thank you blowerbike,
anyone else have anything to offer?
thanks

[BigD_83]

Hey Trevor,

is the vibration noticeable at all RPMs? Does the frequency increase with RPM? Are there ranges where it goes away?

[trevor]

Hey Trevor,

is the vibration noticeable at all RPMs? Does the frequency increase with RPM? Are there ranges where it goes away?

If I'm in 5th gear at 3500rpm it ok but after that no.
It has been mentioned that it could be bars and that it might be unfair comparison to my 83 as there are lots of improvements in bars, pegs, rubber mounting in pegs etc. and I get that, it's just that with stock exhaust on the 81 and 4-1 on the 83 I thought it would be better

[JTGS850GL]

Trevor... for what it's worth, my 1980 GS1000G does exactly the same thing. It's one of the reasons I decided to "upgrade" and replace the engine with a 1983 GS1100G engine. Hope you find the solution. I'll be watching this thread intently.

[trevor]

Trevor... for what it's worth, my 1980 GS1000G does exactly the same thing. It's one of the reasons I decided to "upgrade" and replace the engine with a 1983 GS1100G engine. Hope you find the solution. I'll be watching this thread intently.

Thanks, yeah it doesn't really make me want to ride it when I have choices.

[BigD_83]

Thanks, yeah it doesn't really make me want to ride it when I have choices.

I agree. You should give it away to someone younger, who can tolerate a little buzz.

[mustangflyr]

One thing to consider, I read about this in an old magazine, is that the motor mounts need to be shimmed. The procedure is to loosen the mount bolts and try to settle the engine in it's centered location them look to see if there are gaps between the engine cases and the mounting brackets. If so install washers to fill the gaps and torque the bolts. Seems if the brackets are stressed because of the gap the vibes increase. Did it to mine and it's quite smooth. Also loosen exhaust pipe clamps and mounting bolts to make sure nothing is touching the frame or stressed, whenever I R&R the exhaust it takes some fiddling to adjust everything.

[lemonshindig]

I'm having identical symptoms on a '78 GS1000. I had the vibrations all last season even with my carbs dipped, rebuilt, and synced. I stepped up 2 jet sizes because they were stock but my bike has a Kerker 4-1 and the PO cut a hole in the airbox. The bike is running fine but it didn't help the vibration. If I shut down the engine at speed, the vibration goes away.

My '79 GS1000 didn't have the same vibration.

So if I'm reading this correctly, I am to pull the stator cover off and check the rotor for play? Also check the engine for needed shimming... Got it. I've also been thinking I should see if one of the starter clutch bolts backed out.

The exhaust should be rubber mounted, correct? I haven't checked for that either.

[azr]

You Kerker will not be rubber mounted. Do you have a picture of your bike somewhere, I'd like to see what it looks like, better yet sounds like, with a Kerker.

[hillsy]

Not saying this is definitive, but it can be exhaust related.

I remember back when the new Z1000's came out (2003??) I rode a standard one back to back with one that had a 4-1 exhaust. The difference in engine vibration was very noticeable with the 4-1 bike being so much smoother than the stock one.