Chain tensioning with a Kat shock + dumb tension question

[PachmanP]

So I'm adjusting my new chain, and I'm trying to figure out how much freeplay to give it with my 06 Kat 600 shock. 

ineedanap pinpointed about 1.5 in in this thread, but I'm trying to get it right by checking the freeplay with the suspension compressed to max(ish) tension. Does anybody know how much freeplay it should have at that point?  I found one thing on the interwebs saying .5 in.  Is that right?  How would I even tell if the chain was too tight?

Now for the dumb question... Is freeplay the difference between a slack chain and the pushed up chain, or is it the difference between a pulled down chain and a pushed up chain? I had sort of guess at it being slack to pushed up, but randome guy on the internet seems to think it's pulled to pushed.

Thanks 

[ineedanap]

There are no dumb questions!

Yes, it's the difference between pushed and pulled.  

If it was me I wouldn't get too worried about the magic .5 number.  The important thing is that it doesn't bind.  You'll know if your chain is too tight because it'll be nearly rigid.  I was running about .1 inches of extra slack at max tension and my chain/sprockets showed no abnormal wear.  

If it was me I'd just use 1.8 inches and re-adjust at 2 inches.  That's what Danny got with his Kat shock. 

[burning1]

Chain slack is based on swing-arm and sprocket geometry, not the shock. Use the stock freeplay.

If in doubt, you can always remove the shock, and run the swingarm through the full range of motion. So long as you have some slack when the chain is at it's tightest point, you are okay.

[ineedanap]

Chain slack is based on swing-arm and sprocket geometry, not the shock. Use the stock freeplay.

Except that the shock length affects swingarm and sprocket geometry since their angles are based on position of the shock.  

We don't actually change the pivot points of the swingarm or the chain when we change the shock, but since they don't share a common pivot point their relationship to each other changes at different angles.

With a longer shock we have increased our initial swingarm angle.  The rear sprocket will be slightly closer to the front sprocket at full shock extention (where we measure) than it would be with a stock shock.  The problem is that at it's tightest point (swingarm parallel to the ground) nothing has changed.  It still requires the same amount of slack as it did before we changed shocks.  All has to be factored into your initial setting.

If in doubt, you can always remove the shock, and run the swingarm through the full range of motion. So long as you have some slack when the chain is at it's tightest point, you are okay.  

You're absolutely right about pulling the shock and moving the swingarm thru its range of motion.  That's what I had to do (and everybody should do) to figure out the binding problem. Put in a longer shock and set the slack to factory recommendations.  You'll find that it binds unless you run more initial slack.  

[burning1]

The spring rate difference should be irrelevant*, and as far as I know, the Katana shock and GS shock are about the same length when fully topped out.

* Measure your static sag with the bike sitting on it's side stand. I think you'll find that even with the stock shock, the suspension is fully topped out.

[joshr08]

kat shock lifts bike about 1.5 inches

[burning1]

Is that static sag, or rider sag?

I have a Kat 750 shock on my GS. IIRC, they are the same length, fully extended.

[joshr08]

without and with rider on my 05 is 1.5 inches higher

[burning1]

Huh... Interesting. Okay. My mistake then.