For those that have the 5000rpm vibes

[conradvr]

My GS had started to vibrate really bad at the 5,000 rpm mark and recently started to make a nasty vibe noise around these rms as well.  

When I removed the tank to change the valve shims (clearance was 0.08 - 0.1mm on the 4 valves) I found one of the two rubber grommets under the tank missing.  

So I replaced the missing one with a home made one from some rubber I had.  I also stuck two rubber strips onto the frame where these rubber grommets sit as the originals had been compressed over time (1996 bike).

Took the bike out for a test spin and was pleasantly surprised by no more vibrations.  The fix was most probably the new rubber strips (and maybe getting the valve clearance tighter helped as well).

Hope this helps
Conrad

[nl_carey]

After I dropped my bike I had to fix up the ignition pickups which had been damaged in the fall - during this I also took off the tank, carbs and airbox and had to refit them. After this, the bike had no vibes in the 5000 rpm range anymore, and ran quite a lot better than before too! I think it was mainly the pickups that fixed things, but it could also have been the other items too.
Best thing I ever did was drop the bike really - I replaced the crappy kawasaki mirrors that were on it at the same time...

[nl_carey]

Oh, and just to note, I had previously replaced one of the rubbers on the tank - and it seemed to make things worse - the vibration was made to be a much higher frequency, which was more annoying. Not to say don't do it though (better stability in the tank is good for quick stops), just that it could be related to other things...

[BRB96Z34]

I seem to get the vibrations only when it's cool out.  When we started to get warmer weather the vibrations seemed to disappear.  I'm confused.    I checked the rubbers on the tank the last time I had it off and all of mine are there so I don't know what's causing it.

[vroomvroomvroom]

I think these engines just vibrate quite a bit no matter what you do.  I have tried insulating the s**t out of the tank and seen little improvement.  
I am wondering if maybe removing the balance shaft and having the lower end properly balanced would improve things (I really don't want to spend the money on that though!).

When I jump on my friends SV650, I really realize how much my GS500 vibrates.  The SV650 is smooth as silk, probably the smoothest engine motorcycle I have ever ridden.

[MarkusN]

[Lars]

My engine also vibrated a lot when I just had the bike (it's a '93, bought it with 20.000 km's) First it was restricted to 25kW but after 2 years I could remove the restriction and started to ride it harder. I also switched to using  mineral oil and changing that every 5000 km's.
After a while, the engine became smoother and now it's almost vibration-free at some rpm's.

The difference is big, first I had numb hands sometimes, so much it vibrated. Now you only feel very gentle vibrations if you go over 5000 rpm and if you ride 150 km/h at 7500 rpm it's even completely vibration free like the engine doesn't run!

Maybe I broke the engine in better (After 35000 km's  :dunno:   ) by using mineral oil. I also had that in the engine while I was on vacation. At least 1500 km's at a constant 7000 rpm.  When I came back, the engine was smoother and the topspeed had improved by 10 km/h to 187 km/h.

I think the kind of oil makes a big difference. First I used Shell semi-synthetic, but especially when the oil got older, shifting got harder and the clutch felt like it wanted to slip. With the Castrol GP (Mineral) That all was a lot better. Vibrations were also less harsh. Castrol GPS (semi-syntetic) does exactly the same.

[danci1973]

After I dropped my bike I had to fix up the ignition pickups which had been damaged in the fall - during this I also took off the tank, carbs and airbox and had to refit them. After this, the bike had no vibes in the 5000 rpm range anymore, and ran quite a lot better than before too! I think it was mainly the pickups that fixed things, but it could also have been the other items t

Hey, how were your ignition pickups damaged and how did you fix them?

I'm not happy with the way my bike runs and I've done almost everything I could with those carbs - now I'm guessing something else might be a problem...  And it was dropped too.

  D.

[vroomvroomvroom]

Ignition pickups and ignition timing could be an issue with vibration.  But, if the mounts were being bent in a fall (they are on the right side of the engine) the engine would most likely not run.  

These engines vibrate being a parallel twin.  I haven't ridden a newer one than my '89.  Mine is a vibrator at most rpms below 6000.  I have tuned the crap out of her.  Everything looks good.  

I don't get enough vibration to bother me at the handlebars.  Most of the vibration I feel is thru the foot pegs, gas tank area.  

Another comparison of vibration I recently had is jumping off of a 2001 GSXR750 after a long ride at highway speeds.  The GSXR vibrates at a higher frequencey than the 2 cylinder GS500.  The vibration comes thru mainly at lower city speeds (lets say below 100mph, below 8k rpm).  The gixxer high frequency vibration numbs my hands and lower body thru the pegs.  I jumped on my GS500 after that ride and I found the GS500 vibration to be very liveable in comparison, no numbing of the hands or feet.  I have run into this before, even thou it seems that the 2 cylinder GS can dish out a pretty hard vibration, it tends to not numb the body as much as the higher frequency 4 cylinder.  I know, this is kinda like comparing apples and oranges here with bikes.  I have ridden many 4 cylinder bikes and many 2 cylinder bikes, the 2 cylinder bikes are always less bothersome with vibration over long rides.

[nl_carey]

I found the bottom pickup had been knocked and damaged in the fall (the cover had been knocked clean off and it skidded for a bit).
Initially it worked ok, but the casing had been broken. I thought everything was hunky-dory, and used it for a bit but then it lost one cylinder, and would get it back occaisionally. I found out this was the pickup after some inspection, and taped it down. Things ran well for about 3 kms, then it stopped again, and i found the pickup had gotten too close and been completely destroyed by the crank.
I think that in a previous crash it had been knocked and wasn't working very well (it had marks and stuff on it previously, but worked ok).

Suzuki wants your firstborn child to replace the entire unit from the battery to the pickups (plate and all). I got another damaged one from a wrecker, and soldered off the top pickup and put it on the bottom of mine.

At the same time, I checked to ensure that the pickups were at the same distance from the crank, and after this the bike ran a lot better - in fact, so well I actually started noticing fuel starvation at high speed - I could never tell before as it just ran out of puff

You should also be careful that the crank wasn't bent in the crash, so ensure everything is tight and the crank rotates normally (mine does, but a lot of the nut has been ground off - not my fault - previous crash!).
I wouldn't suspect a frame bend unless it was a serious crash - one benefit of our steel chassis is that it doesn't bend as easily as modern alloy ones. And it actually triggers the pressure pad at lights!