GSX-R750 K7 vibrates in rear end after reaching 60+ mph : Suzuki GSX-R Motorcycle Forums: Gixxer.com

**Moroder** · 09-05-2012, 01:06 PM

Hey people,

I have an '06 GSX-R750 in good condition.
But there's a problem, it vibrates

.
I thought it was the chain's tension, but I've tightened it and it's still the same!

When it reaches speeds above 60mph it starts doing it. When I pull the clutch it's gone. If I pull the throttle it vibrates again (the clutchlever is pulled at that time). When I reach a constant speed and I would reduce the throttle slightly it vibrates even more!

I've checked the enginebolts but they're tightened like they're used to be

Now I've put the bike on the paddockstand and let it run in like 3rd gear.
The chain wiggles around at some point. I've put a little film on youtube. Maybe this is the problem?

http://youtu.be/HPj4NKNcb-c

Please help

**rv6john** · 09-05-2012, 03:00 PM

The chain action in the video looks normal. On the stand there is no load on the chain and wheel so things spring back and forth.

Could you explain the clutch/throttle in/out thing? It's not clear to me what you are trying say.

Obviously, rear tire balance would be speed related, and consitant, but would not change when you pulled the clutch.

How many miles on the chain and sprockets? If they are worn out and you tighten it up, it can cause vibrations.

Are you checking the tension while you are sitting on the bike? Many chains are overtightened due to setting the tension on a rear stand without a load. When the ride gets on the bike and the swingarm moves up, the chain tightens.

**Moroder** · 09-05-2012, 03:27 PM

Dear John,

want I ment to say with the clutch/throttle in/out thing is

In - Lever is pushed in
Out - Lever is released

I don't know if u mean this but I'll see.
Sorry, I'm not English/American

.

I don't know how many miles are on the chain/sprockets. I bought the bike with 12,5k on it. But there are JT sprockets on it with a gold chain.

I've tensioned the chain while standing on the sidestand (like the manual says). I set it to 25mm of play (manual says 20-30mm).
Or is that like totaly wrong?

**rv6john** · 09-05-2012, 04:51 PM

Actually, I was not clear.

This is the part that I did not understand.

"When it reaches speeds above 60mph it starts doing it. When I pull the clutch it's gone. If I pull the throttle it vibrates again (the clutchlever is pulled at that time). When I reach a constant speed and I would reduce the throttle slightly it vibrates even more!"

I'm trying to figure out why the clutch engaged/dis-engaged or throttle change would change the vibration.

**Moroder** · 09-05-2012, 05:00 PM

But did i tension the chain in the right way? Or can you explain me how you do it at your own GSX-R?

**Roeland.Vlok** · 09-06-2012, 04:11 AM

Moroder,
You did tension the chain in the right way! It sounds like the issue is in the drive-train. If you pull the clutch and rev the bike this should not change the vibration levels more than engine vibration levels. My k6 750's previous chain had two links that would not swivel any longer. If the chain can pivot nicely around the sprocket and doesnt have any kinks between the front and rear sprockets while running, the chain should be good. It could be the bearing on the front sprocket, but at 12k i dont think so. Like rv6 said, could it be wheel balancing? Also check the sprocket bolts. How bad is the vibration?

Hope you solve the issue...

**Moroder** · 09-09-2012, 10:47 AM

Well,

I've tensioned the chain again. Gave it a little more tension now. And cleaned it real good now (and obviously greased it again). But sadly no changes. The sprocketbolts are all tight, but I did see 2 links which are damaged (from my sight, just the gold coating).

Roeland, how can I see if the links don't swivel rightly??

**RedGixxer60** · 10-28-2012, 03:58 PM

I had the same problem with my K6. Turns out I had a few kinks in the chain. I changed the chain and sprockets and problem when away hope this helps.

**Moroder** · 11-07-2012, 03:08 PM

Quote:

Originally Posted by RedGixxer60

I had the same problem with my K6. Turns out I had a few kinks in the chain. I changed the chain and sprockets and problem when away hope this helps.

Changed the sprockets and chain (even though the "old" ones were fairly new looking). Still vibrates

.

It seems like when I give the clutch lever less slack it vibrates less. But this only counts for the vibrations when driving constant speed/decelerating.
The vibrations at acceleration are still there, no matter what.

I also noticed the vibrations will be worser when taking it for a long ride...

**QuietRider** · 11-08-2012, 04:45 PM

This all sounds to me like an engine problem - uneven torque output when using power. A cylinder not putting out as much power as the others can cause this. I would start by checking the spark plugs. After that I would check compression on all cylinders. It could be an injector problem too.

**Moroder** · 11-12-2012, 04:15 PM

Quote:

Originally Posted by QuietRider

This all sounds to me like an engine problem - uneven torque output when using power. A cylinder not putting out as much power as the others can cause this. I would start by checking the spark plugs. After that I would check compression on all cylinders. It could be an injector problem too.

Checked and changed the plugs (the old plugs were fairly new / in good condition). All the plugs had the same color, so I guess that's ok

.
After I changed the plugs, I balanced the TB's (Cyl 2&3 were slight off).

The bike doesn't seem to having combustion problems, it's fast as hell

.

Can't there be anything wrong with the clutch?