Chain guide rubbing.

[etorty]

I put my new chain guide on about ten days ago.
I've ridden for about 1200 km, and the "new" chain guide is like you see:
 

 

 
I was searching for any fault or any thing that I can do in order to improve the lasting of this piece of rubber.
No way: there's only one way to mount it. And it seems that the guide, without any fixing system in the middle (of the upper section) tends to bend in the outer direction.
The rubber (this is an OE Yamaha replacement) seems to be even softer than the original guide.
I will be very surprised if it can last 15k km.

[Guest ChicagoAJ]

If your chain is sitting on the raised portion of the guide, your rear wheel/sprocket might be misaligned. My chain rollers rest on the raised portion of the guide when the wheel/sprocket is straight, (according to my MotionPro alignment tool) but it does seem to be a bit off center and the chain is closer to the ribbed portion of the guide on the clutch lever side of the bike. The chain guide is also super floppy, so I'm sure it scoots around whenever it's hit by the chain. 
 
Have you checked your wheel/chain/rear sprocket alignment?
 
 
I wouldn't worry so much about yours. Mine was eaten through to the swingarm but the raised center portion was barely touched (chain was too loose). 

[etorty]

@ChicagoAJ, I was sure that the rear wheel was correctly aligned (anche the chain slack was already ok), but I've checked another time with an "home made" tool.
This tool is home made, but it's reliable.
The result: no difference between left and right measurement.
 

 

[rick]

Have to wonder if some of these swing arms are not centered properly.
 
Does the front sprocket on this bike have an offset? By that I mean, do the teeth sit off-center? Maybe some have been installed inside out and that's what's causing the chain to be off-center.
 
I don't have the miles on mine that a lot of guys do, but my guide looks pretty much new. My chain's not dead center over the ridge, but sure close enough.

[markstertt]

Well it would appear my guide is also wearing in an off center fashion, it's also rather floppy and has assumed a mild 'S' shape from front to back with the aft end of the top run more inboard than it should be but of course it's pinned there by the hole in the swing arm. I haven't rechecked the wheel alignment or looked any further yet but found that the paint on the swing arm, under the center area of the guide, is worn off so perhaps the prior owner replaced the guide after having a problem with the original. Or perhaps debris under the guide wore the paint off, although initially it looks like chain slap damage. My bike has a bit over 8000 miles. I'm a bit suspicious about whether or not the c/s sprocket and rear sprocket are in the same plane as I was meticulous about chain alignment measuring between machined pins inserted in the swing arm pivot and rear axle. More investigation is necessary for sure.

[rick]

those guides are really free to move about a bit. It wouldn't surprise me if road dirt gets between the lower guard and the paint and the paint suffers - it's not exactly thick.
 
That the guide is no longer straight is interesting. Everyone is so hot to clean the chain, wonder what effect kerosene or other solvents is having on that piece of rubber? Only thing my chain ever sees is a mix of gear oil and Li based grease.
 
I seem to recall someone mention the front sprocket having some rubber on the inside meant to damp out some vibration. I would think the rubber would face inward if that's the case.
 
 

[Guest ChicagoAJ]

those guides are really free to move about a bit. It wouldn't surprise me if road dirt gets between the lower guard and the paint and the paint suffers - it's not exactly thick.  
That the guide is no longer straight is interesting. Everyone is so hot to clean the chain, wonder what effect kerosene or other solvents is having on that piece of rubber? Only thing my chain ever sees is a mix of gear oil and Li based grease.
 
I seem to recall someone mention the front sprocket having some rubber on the inside meant to damp out some vibration. I would think the rubber would face inward if that's the case.
 

Rubber is on both sides of the drive sprocket. The chain sits on it when on the sprocket, but the rubber gets worn in after a while by the chain. 

[rick]

Ah, I guess both sides makes sense. But is the sprocket symmetrical with a faced in side ? Can it be put on the output shaft wrong side out?

[Guest ChicagoAJ]

Ah, I guess both sides makes sense. But is the sprocket symmetrical with a faced in side ? Can it be put on the output shaft wrong side out?

Sprocket goes on either way.

[etorty]

Have to wonder if some of these swing arms are not centered properly.  
[...]

My swing arm is a little bit off-center. Looking at the frame, the space between the frame in the left side is about 3,5 mm.You can see that in the pict:
 

 
I can't do a photo at the right side, but I can see a space of about 1 mm or 1,5 mm. No more.
 
The swing arm of the MT-07 of an Italian friend is more centered:
 

 
maybe this is a little bit off-center (less than mine), but in the opposite way.
 
I think that if my swing arm will be more centered (1,5 mm in the right direction), the chain guide will be more centered under the chain, and the wear maybe will be less than now.
 
I've loosened the bolt of the axle of the swing arm and I've tried to push the swing arm in the right direction, but it is firm.

[Guest ChicagoAJ]

Mine is centered, @etorty. But where the gap is that you have - a dust cover is working its way out on my bike (red arrow is pointing to it). It's in the shop now getting fixed under warranty along with other issues. I've decided I'm likely getting rid of this bike halfway through next season and getting a GSX-S1000 over the winter.
 

 

[etorty]

The gap that I've is between the swing arm and the frame in the center of the bike.
 
I've seen the dust cover that you've highlighted with the red arrow.
In my bike this was shifting just a little (about 1 mm, only in one point) off the metal cover that's between the swing arm and the rearset's plate.
Sunday (when I've loosened the swing arm nut) I've fixed this little problem and now the dust cover stay at his place.

[Guest ChicagoAJ]

I've tried pushing mine back in a few times. Comes out after a few miles every time. I'll let the dealer replace it and the bearing.

[etorty]

Mh... it seems that I have another thing to survey time to time... 
Thanks, @ChicagoAJ!

[markstertt]

So I reinstalled the rear wheel and chain and checked the guide and it appears that the front and rear rib does indeed rest beneath the center of the chain, however, the center of the guide bows to the outside and is grooved by the chains outside plates. Might just get a new guide and adhere the center with an adhesive, I only wish it was made of tougher material.
 
While playing with the guide/chain and rear wheel, I noticed that the rear sprocket has about .020-.025" runout, wheel looks ok but need to check sprocket and carrier now. Anyone else notice this on there bike?

[Guest ChicagoAJ]

So I reinstalled the rear wheel and chain and checked the guide and it appears that the front and rear rib does indeed rest beneath the center of the chain, however, the center of the guide bows to the outside and is grooved by the chains outside plates. Might just get a new guide and adhere the center with an adhesive, I only wish it was made of tougher material. 
While playing with the guide/chain and rear wheel, I noticed that the rear sprocket has about .020-.025" runout, wheel looks ok but need to check sprocket and carrier now. Anyone else notice this on there bike?

I was using a Motion Pro chain tool to check sprocket/chain/wheel alignment. Ended up having the brake side adjuster plate about half a hash mark behind the sprocket side. The tool says the sprocket and chain are lined up, but looking down the chain to the front sprocket, it's not perfectly straight, that's probably why the chains on these bikes are set to be so loose.  
The sprocket carrier is only press fit into the rear rim and then smashed with the spacers by the axle, so there's no way it's going to be perfect. I've decided if things are close enough with this bike, then that's just going to have to be good enough because it's not worth the time spent to get everything exact. 
 
Also, my brand new chain guide is exactly like yours. The center of the guide bows outward and the chain seems to ride on the rib until right after the footrest and then the rollers of the chain ride the rib to the end of the guide. If I didn't let my chain get loose, I'm sure the old guide would've lasted longer than 3,800 miles. I'll see with the new one, I guess. 

[rick]

I would definitely clean the swinger and the rubber guide and tack it down with a couple dabs of RTV silicone so that it's straight. That'll be most of the battle.
 
Sprockets made for these bikes are usually just stamped chunks of steel. Combine that with the fact that they are basically rubber mounted in those cush blocks, there's always gonna be some play. The sprocket might not even spin perfectly centered so there might be some up and down to the chain as it goes round that back sprocket.
 
As for the specified play, well, it's probably more about the width of the swinger where the chain is, the geometry and angles created by where the swinger pivots in relation to the front sprocket, the length of the swing arm and then throw in sprocket diameters.
 
And just my own personal preference when it comes to rubber bits and solvents. I wouldn't get any solvents of any kind on that rubber guide - that includes the kerosene that lots of folk like to use for cleaning the chain. Maybe a short exposure to kerosene doesn't hurt chain the o-rings, but who knows what it might do to that guide - maybe making it harder or maybe softer causing it to swell a bit.
 
Maybe that 2" play is a compromise that Yamaha had to use, but chances are if you run the chain tighter, more expensive bits ( and harder to replace if in the gearbox) than that rubber guide will toast
 
 

[markstertt]

The 2" play doesn't appear to be a compromise Rick, it's pretty much spot on and if you remove your shock and raise the swing arm so that the c/s sprocket center, swing arm pivot and rear axle center are all in a straight line you'll find that the chain tension is neither to loose nor to tight.
 
 
I'll remove the sprocket and carrier and see what's up, if it's the cheap stamped sprocket, then I've got a good excuse to upgrade to a 17/45 combo, my original set has a bit over 8000 miles but still has many miles left.  Anyway, the larger diameter sprockets should help with keeping the chain off the slider prolonging it's life and tacking down the center of the run with some adhesive is also a good idea.
 
I'm also thinking that adding a spring loaded chain tensioner on the bottom chain run might be a good idea, less chain slap, less vibration perhaps. There are several mfg. of these tensioners that use a skate board type wheel or in some cases a small sprocket, either way with the lower run under tension there should be less slap in the top chain run when off throttle hence less possible contact with that upper rubber guide. In the old days, swing arms had less droop, less anti-squat if you will so this chain to swing arm contact wasn't as big an issue, I'm talking street not dirt bikes.
 

[rick]

Probably shouldn't have called it a compromise. But yeah, it's all about those angles.  it's likely with those 3 points (front sprocket, pivot and rear axle) in line, If the chain slack was only an inch with the bike on the sidestand, it would be way too tight with the suspension compressed.
 
By comparison, the chain tension on my Aprilia is measured with the bike on the centerstand - so full extension where the chain will be loosest - and the slack is spec'd at an inch! That single sided swinger is massively tall on the chain side.
 
Would have to do some measuring and drawing to understand why such a big difference. That bikes guides are now 14 years old and have a bit of wear - not enough to think about replacin' them though
 
I'm happy to just use what Yamaha recommends for this bike. I was ultra fussy with my 1st chain after decades of drive shafts back in 2003. Not so much now. Set it and forget it - with a bit of gear oil in between.
 

[peteinpa]

How many of you have the 520 chain? It's narrower, harder to stay on the ridge.

[Guest ChicagoAJ]

I'm running stock chain.

[etorty]

Me too: stock chain and stock sprockets.

[motocr]

Found the issue with my chain, after waiting 2 month for the chain guide to come in. My chain got onto the guide and wore a new line into the guide instead of the rollers being the only contact point the side of the chain cut a new groove into the center area I replaced the guide it all works fine. I'll upload a picture of the old guide tonight.

[markstertt]

Found the issue with my chain, after waiting 2 month for the chain guide to come in. My chain got onto the guide and wore a new line into the guide instead of the rollers being the only contact point the side of the chain cut a new groove into the center area I replaced the guide it all works fine. I'll upload a picture of the old guide tonight.

I took a short 1" pc. of thin dbl. sticky back foam tape and adhered the center section of the guide to the swing arm, the guide now stays centered under the chain and has stayed put over the last couple hundred miles. While cleaning the swing arm and under side of guide with acetone (before applying the tape)I noticed that debris trapped under the flexy guide had abraded thru the swing arm paint, once stuck in place, the guide won't be able to do this damage. 

[avanti]

In looking at ALL this, I think the most common issue (though probably not the only one for some) is simply a crappola chain-guide from the manufacturer... pure and simple. It's not a very good design from the git-go and it isn't particularly durable, in any sense of the word... it wears and warps, etc. Fortunately, it's cheap and easily replaced.
 
And, if you are going to error, don't adjust the chain too tightly, usually potential damage is far greater than too loose. And, either before your very first adjustment OR when absolutely sure your wheel is aligned correctly, mark the top of your two nuts (adjusting, of course) before turning them; then, turn them BOTH the exact same amount to adjust the chain. This has never failed me.