Chain Adjustment Issue

[z0sum]

So earlier today, I checked my chain slack and it was pretty loose. So I put it up on a rear stand, loosened the main bolt in the tire and tightened it up until the slack was about an inch, since I knew the spec calls for between .8 and 1.2.

Got it in spec, used a screwdriver to keep the slack still while I tightened the main bolt back up. So then I ride around some, get back home. Now when I check the slack it's super tight. There's next to no slack in the chain, as if I tightened it too much.

Before I went to ride around, the slack was perfect. What happened?

[CaliGrrl]

Some parts of the chain are looser than others. Rotate it around until you identify the tightest spot of the whole thing, and adjust to that.

[jkv45]

Watch this video - http://canyonchasers.com/video/howto/chain.php

[CC Cowboy]

Originally Posted by jkv45

Watch this video - http://canyonchasers.com/video/howto/chain.php

Nancy really knows his stuff!

[z0sum]

So I checked the slack again today. The last I rode was yesterday. When I checked the slack now it's sorta okay again, if anything now a little on the loose side, but fine overall. I did spin the wheel to feel the slack change a little, but it seemed way better than yesterday, when it seemed to have no slack after riding a bit. This is a little confusing, what's happening?

[RacinNinja]

Chain warmed up since you rode it? Did you check it right after a ride?

Might have some old lube creating a sticky spot. chain might need a good scrubbing with kerosene and a chain brush.

[z0sum]

Originally Posted by RacinNinja

Chain warmed up since you rode it? Did you check it right after a ride?

Might have some old lube creating a sticky spot. chain might need a good scrubbing with kerosene and a chain brush.

Yes I checked it right after a ride and it was tight. Just rode it a little more and it seems as the bike warms up the chain gets tighter. Is that normal?

[Motofool]

Originally Posted by z0sum

........
Before I went to ride around, the slack was perfect. What happened?

First, verify that there is no appreciable play at the pivot points of the swing-arm.
http://faq.ninja250.org/wiki/Servicing_the_swingarm

What keeps the rear wheel from sliding back and forth in the swing-arm is the torque of the axle bolt rather than the adjusters.

If the axle is loose, the wheel could move slightly forward under acceleration and slightly aft under rear braking.

Tighten the axle bolt to 80 ft-lb (108.4 N-m) with the torque wrench on the crown nut and another wrench keeping the head of the bolt from rotating.

If you can, use a helper to hold the bike, kick the tire forward at the beginning of tightening and push both wrenches forward at the end, so both adjusters are fully under tension, with no longitudinal play.
Your slack should be consistent that way, as the wheel is as forward as the adjusters allow it to be.

Then, verify that the alignment of front and rear tires is more or less correct.

[rgx107]

I have had the same experience on the 300, which I think has the same rear suspension. The recommended 20-30 mm is too tight, even if you measure on the tightest part of the chain. 20 mm is definitely too tight.

I am adjusting the chain less tight now, there was a thread about the pregen recommending 35-45 mm, which is about where I'm at.

It seems unlikely that the chain could get tighter when warming up. I would expect the opposite, that the swing arm would heat up less than the chain so you get more slack, not less. Assuming they are similar materials, steel in both cases.

[jkv45]

Originally Posted by z0sum

So I checked the slack again today. The last I rode was yesterday. When I checked the slack now it's sorta okay again, if anything now a little on the loose side, but fine overall. I did spin the wheel to feel the slack change a little, but it seemed way better than yesterday, when it seemed to have no slack after riding a bit. This is a little confusing, what's happening?

I would re-check it again.

Get the wheel up in the air and locate the tightest spot - take note of where the valve stem is. That's the most important point, and the place to start.

After you have set the slack properly at that point, check every 90 degrees to see how much it changes. If the change is excessive it means there is an issue with the chain or sprockets and it may be time to replace both.

[CrazyCanuckGoat]

The pregen spec is with the bike on the centerstand. Newgen specs are for both wheels on the ground on the sidestand. Don't use a rear stand (spools), your chain will end up too tight just like this situation.