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Could be a few links stuck together. Don't have a really good way of explaining. ___/\_____ sort of like that.
 

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Hi all,
yesterday I noticed a wobble through my footpegs, it seems to be coming from the rear of the bike, like the wheel or chain.
It's not a wobble like the bike itself is wobbling, but a part is.

I put the bike up on the rearstand, and just let it run in 1st gear.
I can feel a little wobble every couple seconds, I think it's the chain, as i can see the plastic chain guard/slider on the swingarm moving side to side a big (the one the chain slides along right at the front of the swingarm)

Tightness on the chain seems fine, it also seems to be lubed OK.
It's got almost 13,000km on it.

Any ideas what could be causing this?
 

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Since you were still getting it with the rear off the ground, it doesn't sound like a wheel prob. How about maybe a worn sprocket? It'd probably happen more than every couple of seconds if that was the case though. Might be a good excuse to switch to a 520 chain combo though [8D]

Just my thoughts, but I'm no mechanic.
 

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Did somebody chime???


Elimate the obvious, wheel balance.........
My first thought would be, as stated (Nexus), tight links...aka tight spot in the chain.

Spin the wheel by hand slowly and feel for the possible tightness.


Jason
 

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Wheel balance is often the culprit for this sort of thing. I would also suggest doing it 'right'. Nearly everyone mounts the tire improperly, including the dealers and professional shops. It's nothing but an old bad habit. I'll bet you'll find that the yellow dot on your tires is lined up next to the tire valve. The wheel should first be placed on the balancer (before mounting the tire) to find out exactly where the 'true' heavy spot really is. When you have done this as many times as I have you'll discover the the tire valve has nothing to do with it. I often find the tire valve to be the lightest spot, so most mechanics would be installing the tire's light spot right next to the wheel's lightest spot. Actually, the worst situation is when they're off by about 90 degrees. This typically results in a problem like you describe, even when the 'assembly' balances just fine. I have often had customes complain about a noticable wobble right after getting a new tire. You guessed it, the yellow dot is right next to the valve. Re-mounting and doing it right makes a big difference. Just something else to keep in mind.
 

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So Dave.......What does the yellow dot represent?

Why do the manufactures put it there?......Naturally, one would assume a light spot.

So you balance the rim first, then balance a second time for the tire balance on the balanced rim.

Right?

Jason
 

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It sounds to me like the wheel may be out of alignment, not balance. Did you recently tighten your chain? If so, make sure both sides of your axle are lined up with the swingarm marks. The chain going back and forth as you said earlier would be a symptom of an out of alignment wheel. Put it back up on the stand and put it in fifth or sixth gear and stand back and watch the wheel for any side to side swaying.
 

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Badassjake,
I think you've got the right idea, but your terminology is a bit inaccurate. You're not actually balancing the wheel but only placing it on a balancer to find the heavy spot. Don't balance it though, just mark the spot. The yellow spot does indeed identify the tire's light spot. Some tires use red dots while others don't provide the information and others still are perfectly balanced and therefore have no marking at all (Michelin)
 

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Cool Dave,

Normally, (at the shop)when I balance a tire,all is well. On occasion there comes in an older machine(GPZ,GS,etc.),with a wheel that seems to take more than usual wheel weights to bring er around. Naturally I assumed that there was a heavy cast for the rim.

Most newer ones seem to take no weight or 7-10g.
I do recall, in memory,a friend of mine that used to race say that there were some guys at the track that just balanced their rims to save time for tire swaps during the race days events.

A subtle thing, rim weight, but easily over looked.

One question, I noticed a rim the other day on a sport bike that had weights in two completely different spots(say 12 and 4 oclock)(not race balanced )....what gives with this?

I've never had to do this.

Jason
 

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Discussion Starter #12
I check the wheel balance every time I mount a tire. I have not come across any where the heavy spot wasn't at or near the valve stem.

You can balance a tire by splitting the weight. Find the amount of weight that will balance the tire then take that amount of weight and place it 60 degrees on either side of the light spot. It will run smoother and you can make a fine adjustment by altering the angle. Narrowing the angle has the effect of increasing the weight, widening the angle decreases the weight. This might be what you saw.
 
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