Chain tension thoughts...

[Magnus]

I'm wondering what the general consensus is on this...  the Ducati manual instructs setting it unloaded, ie. no rider.  But the chain gets tighter as the shock compresses, so theoretically if the chain is too tight it could prevent the shock from compressing all the way.  You can do some serious damage with a too tight chain, like frying your output bearing.

So...  better a little too loose than a little too tight?  I read somewhere that the chain should be loose enough to touch the lower slider on the bottom of the swingarm by pushing up on it lightly with one finger.

[Speeddog]

Whether or not your chain should be able to touch the bottom slider depends on a lot of things:

Shock spring preload
Whether you've adjusted the pushrod or yoke
Whether you have a stock length shock
Sprocket sizes
Whether you've repositioned your forks
Fork spring preload
Stock or aftermarket sidestand
On a single sided swingarm, where the eccentric is positioned
Probably a couple other things too....

Generally, a little too loose is better than any amount of too tight.

[johnster]

I used to be really anal about chain tension, thinking that too much either way (loose or tight) was bad, but it's ALWAYS better to run it too loose than too tight.....You're much more likely to cause expensive damage to the driveline with it too tight...

-Mine has a little bit of slop in it right now which makes driveline lash (going from throttle off to on) more annoying, but w/the right throttle/clutch control you can get around it.....

[hypurone]

I used to be really anal about chain tension, thinking that too much either way (loose or tight) was bad, but it's ALWAYS better to run it too loose than too tight.....You're much more likely to cause expensive damage to the driveline with it too tight...

Yup, and mine keeps setting its own tension anyway, no matter how much I fiddle with keeping it "right". Everything is tightened properly but it doesn't matter, I always get end up with a slightly loose chain. Too much power and application of that power is my theory!   :e:v  Damn bike has a mind of its own!!

[Magnus]

why measure tension on an unsprung bike?  it just seems that it would be better to check it while it has a riders weight on it...  but hey, what do i know?

[johnster]

Yup, and mine keeps setting its own tension anyway, no matter how much I fiddle with keeping it "right".

Absolutely....Mine has loose spots and tight spots, and I got sick of always tightening it just to find that it's loose again in spots...I sorta just stopped caring, although a new chain isn't too far away I think....

[Speeddog]

Here's the *absolute* best way to do it.

Compress the suspension until the centers of both sprockets and the swingarm pivot are all on a straight line.
This is the condition under which the chain is the tightest due to the geometry.
Rotate the wheel to find the tightest spot, there's some small variations in sprockets and chain that make the chain tension vary.
If you notice a *bunch* of change in tension, you've got a chain or sprocket issue.
Set the adjusters so that the chain has a little bit of freeplay.

Then, put the bike into the condition under which you want to normally check chain tension.
On the sidestand, on the centerstand if you have one, on a rearstand, whatever.
Accurately measure the distance from some part of the rear of the frame (bottom of the seat lock bracket, for example) to the rear axle, so that in the future you can confirm that you've got the suspension in the same position.
Then measure how much freeplay the chain has.
Use these two measurements as your 'master'.
Any time after that, you can adjust the chain with confidence, as long as the frame to axle distance is the same.

[ScottRNelson]

Here's the *absolute* best way to do it.

Compress the suspension until the centers of both sprockets and the swingarm pivot are all on a straight line.
This is the condition under which the chain is the tightest.
Set the adjusters so that the chain has a little bit of freeplay.

You missed a step: Check for the tightest spot of the chain first.

[hypurone]

Here's the *absolute* best way to do it.

Compress the suspension until the centers of both sprockets and the swingarm pivot are all on a straight line.
This is the condition under which the chain is the tightest.
Set the adjusters so that the chain has a little bit of freeplay.

Then, put the bike into the condition under which you want to normally check chain tension.
On the sidestand, on the centerstand if you have one, on a rearstand, whatever.
Accurately measure the distance from some part of the rear of the frame (bottom of the seat lock bracket, for example) to the rear axle, so that in the future you can confirm that you've got the suspension in the same position.
Then measure how much freeplay the chain has.
Use these two measurements as your 'master'.
Any time after that, you can adjust the chain with confidence, as long as the frame to axle distance is the same.

OK, now THAT is anal!  ;:|  ;:|  ;:|  ;:|

[Speeddog]

You missed a step: Check for the tightest spot of the chain first.

Fixed. Thanks! 

[Howie]

Ducati bases the spec on a stock bike at factory ride height.  Since bike weight is the same and rider weights vary as long as the bike is reasonably stock unloaded works fine. 

[Old-Duckman]

Yup, and mine keeps setting its own tension anyway, no matter how much I fiddle with keeping it "right". Everything is tightened properly but it doesn't matter, I always get end up with a slightly loose chain. Too much power and application of that power is my theory!   :e:v  Damn bike has a mind of its own!!

Sounds like you need a new chain. When a chian is shot it will not keep an adjustment.

[mitt]

I have about 10mm of difference depending if I am in the loose part or tight part of the chain.

I always thought it was the OEM sprockets.

I replaced chain and sprockets last fall, and guess what - same difference.

It seems to be consistent with rear wheel rotation, so maybe it is the carrier?  Maybe it is the cush drive hole locations?

I could use a height gauge and figure it out, but it doesn't seem to bother anything.

mitt

[Armor]

My chain tension seems very consistent, with no tight spots.

[hypurone]

Sounds like you need a new chain. When a chian is shot it will not keep an adjustment.

Doubt it with 6K on it, always lubed and "attempted" to keep adjusted. No kinks, rust or other wierdness. It just runs looser than I like, so now I don't worry about it and it hasn't gotten beyond this "zone" it likes to live in.  <shrug>