Hello everybody! I've been using this forum for quite some time now and decided to make my own post as I have an issue with my gs that I can't figure out.

First, a little background of the bike-

It's a 1999 GS500e that I bought last year (2017) with around ~10,000 miles. Was not running (carbs needed cleaning, oil changed as there was nearly A GALLON of gas in the crankcase due to stuck floats during winterization from the previous owner). After I got it running well and did all the maintenance it needed, I got my motorcycle license at age 16  and road all of August, September, and half of October and put around 2000 miles on the bike.

In August when the bike had around 10,800 miles, I had parked the bike in a parking lot after a short ride. However, when I got back to it in a couple of hours to ride home, it was making a strange rattling or buzzing noise coming from the engine, but only at certain rpm ranges, mainly from 4.5k - 5.5k and from 6.5k to 7.5k. It was not making the noise before, and it would make the noise at those same ranges whether I was riding or revving it while it was stationary, and also with the clutch either in or out. Nothing made a difference. I didn't notice any decrease in performance however and continued to ride it until I winterized it in October. I would like to get it fixed ASAP though because I am worried something could be wearing down in the engine, and I just hate the sound.

Has anyone else had this problem? Any help would be greatly appreciated!

it's not the drive train, so start simple and check for any loose fasteners connecting to engine, etc over time everything loosens up from vibration. if thats not it, i'd check cam chain length and cam chain tensioner. how's your clutch feel?

The clutch feels fine to me, not too loose or too tight. However, I've only ever ridden one other motorcycle so maybe it's not as good as I think. I've checked everywhere I can think of for loose fasteners but I'll check it out again just in case I missed something. How tight should the timing chain tension be? I currently have the valve cover off for a valve job so it would be a good time to check that out.

Service manual lists a tolerance for cam chain length, if the chain has stretched beyond that limit, I suppose it could create a vibration, although I personally havent seen this happen. The cam tensioner also has a spec in the SM, and when that fails the cam chain sags, and that could cause vibration too, not to mention your valves may not being close/opening at the ideal times. Im NOT SAYING this is your current problem, but if you have the head off already, it's worth checking both of these anyway. My 10 year old bike had a cam tensioner that was bad.

Okay. I'll check those things out. Thanks for the suggestions.

i had a rattling noise which drove me crazy around 4000-5000 rpm.It was a center stand vibrating against the exhaust bit where there must have been a little rubber damper for stand to rest against when pulled back. sorted that out and no more horrible noise

Cheers,
Lauri

Funny, I've just noticed a similar problem today! I'm getting a garage end of the month so I'll be able to pull it apart and see if I can find out what's going on. It's like a periodic vibration at 5k RPM.

Thing is, it wasn't there when I sat it in neutral and revved it, making me think (hope!) it's just yet another random thing on the bike vibrating at those revs (I figure if it were transmission related, it would most likely happen whilst coasting with the clutch in, which it doesn't).

So much bike work I've wanted to do but haven't because of having to do everything outside. Well, fingers crossed it makes it to the end of the month without grenading!

I had a knocking noise once it turned out that the 3 bolts that hold the starter clutch on the back of the rotor were stripped causing them to knock together.

Also another rattle I had was the rubber that the tank sits on was missing causing the tank to rattle on the frame but this wasn't always noticeable, only at certain revs

My bike has a similar noise from time to time, it's the bolts on the bottom of the tank that hold the U-shaped bracket on getting loose over time. Next time I have it apart I'll loctite it.

Another time I had a similar noise at specific RPMs, it was the right side foot peg mounting plate had a loose bolt. Another good spot for some loctite.

There's about 100 things on my bike that get rattly, truth is I keep just tightening them one at a time but the whole bike needs a complete tear-down, frame repaint, then on reassembly clean and chase all the threads and then loctite just about everything. By now seems like the whole bike wants to come loose.

Update:

Finished spring maintenence last night. Replaced exhaust shim on left cylinder. Was my first valve job since owning the bike. The valve apparently had NO CLEARANCE (clearance was tighter than my smallest feeler gage with 2.65 shim - replaced with 2.60 shim and clearance was .05 mm). Yikes    . Also gave the tank bracket some more cushion as I don't have whatever rubber piece was supposed to be there. When I started the bike, warmed it up, and revved it, I only observed the noise at the lower rpm range (4k - 5k), and it didn't seem as prominent. Maybe something I did affected it. Anyway, I'm just going to wait until I do some more riding this season and see how it is on the road...