Chain shifting

[Jamieg285]

I was pushing my bike into the garage and notice a repeating click/ting noise.  After some investigation I found the following:


When on the centerstand and rotating the rear wheel slowly forward I can see the chain is hard to the right as it passes over the top of the sprocket.  As it passes around, the chain slips to the left (which is what is making the noise), so that when it is on the bottom half of the sprocket it is hard to the left.


Is this normal?


I tried to work out the physics of it, wondering if it was caused by the wheel not being align properly, but I figure it's an up-down misalignment, not front-rear.


I also wondered if this might happen if the chain was too tight?


Any ideas?

[darrsi]

Wheel alignment is easy enough to check on the notches, just make sure they're exactly the same.
Have a careful visual look at each link of the chain along the bottom, they should all look horizontal, if you see any that are slightly at an angle then they may be siezed up. If there are any, i'd firstly spray lube over them and see if they'll free up using a pair of pliers, they could just be a bit dry. If there's any that aren't really budging at all then you'll be looking at a new chain.
The fact that it moves from left to right does sound more like alignment though.
Chain slack should be around 35mm when aligned properly, you need to adjust it very gradually each side to get it spot on.
You need to keep the chain lubed up much more than normal in this wet weather as well.

[Fazerider]

Assuming the front sprocket is secure on the shaft it's hard to see how such a vertical misalignment could develop unless the bike's been in an accident and the swingarm or frame is twisted.
I suppose there might be enough free play in the slots on the swingarm for the rear wheel spindle to be misaligned in that direction, but if the nut was tightened with the bike on the centrestand  gravity should have made that very unlikely.

[Jamieg285]

The chain is in good condition, and this movement occurs with all links.  It's scotoiled and it's turned up for the weather.  The spindle is aligned equally on the adjustment notches. 


I'll have a another look at the chain tension and see if there is any up/down movement on the spindle before I tighten it.

[darrsi]

Take the front sprocket cover off and have a quick look to make sure there's nothing sinister going on under there, just to eliminate it.

[unfazed]

As Darrsi says, take off the sprocket cover and check inside. Your front sprocket may have fallen off allowing the front sprocket to move around. How worn is the chain, can you lift it off the rear sprocket?

[CharlieDee]

Just a note chaps... dont always assume the notches are exact on the swing arm... I found 2mm difference from one side to the other after measuring up with a digital vernier caliper. 2mm can have a huge impact as I had a similar problem myself with the chain and uneven tyre wear. Which ended up in a new tyre and chain and sprockets. :'(

[Lawrence]

What's the best way to align it without relying on the marks?

[darrsi]

Use the marks initially, but if you still think it's out then adjust gradually using eyes and ears while spinning the wheel, when it's right it should all just glide smoothly with minimal noise.

[CharlieDee]

You can also get a laser chain align tool for about £15 from M&P or Fleabay... I have one and it does the trick spot on!! 

[darrsi]

You shouldn't have to pay anything to adjust a chain, i'm sure everyone else manages just fine with eyes and ears?

[CharlieDee]

Darrsi sometimes its nice to have reassurance... especially with the chain... not everyone on here are experienced and seasoned mechanics  :rolleyes and I think you will find there is a quite a few foccors who use some form of alignment tool/device

[taylor]

mine is the same, the notches are out so eyes and ears for me ,

[Andy FZS]

CharlieDee... Where did you measure "from / to" to decide the alignment marks were wrong?


Andy

[wezdavo]

I measure from the swingarm pivot to the rear axle bolt..
You can also check wheel alignment using string while your on..
I must say though the lines etched on the swingarm are pritty close to perfect on mine..

[CharlieDee]

Andy, I took the measurement from with in the axle/spindle carrying slot.