Chain adjustment / correct tension ideas please.

[mudguard]

Installing a new chain and wanting info for correct tension / adjustment. May seem second nature to most but wanting to know your methods as could be different options?
Is the amount of chain slack different for different suspension set ups, eg, monoshock, twinshock or linkage?
Is the adjustment measured with the bike suspended on a stand, bike off the stand, or bike with rider sitting on it?
Is the measurement taken from centre of swingarm on top edge?

[pokey]

What you dont want is a chain that tightens so much when suspension compress that the chain is tight as it will snap. Thats your adjustment rule and why long travel bikes run spring loaded chain tensioners.

[bazza]

What bike???  Then you will get experienced answer

[skypig]

The best way:

1. Identify the tightest spot (if applicable - not required with a new chain.
2. With the bike supported remove the rear shock/s
3. Raise the back wheel until it it a straight line between CS sproket, swing arm pivot, and rear axle. (I support the wheel in the position with "shims" of wood. Use stringline or straight edge for lining up the three points)
4. Adjust the chain to be free, but not loose in this, the tightest position. (I'd err towards loose if any doubt exists)
5. Install shock/s
6. With the wheel off the ground measure free play in a way you can repeat for the rest of the bikes life. This, is your correct adjustment - record it.

Have I explained that ok?

[mick25]

The tightest part of your chain is when the swingarm is dead straight with the centre of the front cog and centre of swingarm pivot bolt and centre of rear axle.
Best thing is to do is remove then rear shocks or mono shock and while on the stand get the swingarm straight and get the chain ten right say 10mm -15mm
Then put the shocks or shock back on then find a mark under neath the swingarm near the front say 150mm back from the  swingarm pivot and push the chain up under Neath the swingarm while the bike is still on the stand write this measurement down .
This will make things easy when you want to check chain tenshion , it may sound a bit hard to work out , I have a peice of alloy the right length .
I Just put the bike on the stand then fit the alloy peice between the swingarm and chain this gives me the spot on chain tenshion with out trying to sit on the bike and try to get the swingarm straight and leen down and check the tenshion .
The ktm 2011 530 has the same idea they stole mine , I removed the shock on the ktm and checked it and it was spot on while the bike is on the stand you push the chain up under the swingarm near the front and it has a sticker on the swingarm 8mm to 10mm gap for chain tenshion .

Hope this helps or makes sense .
I like chain rollers instead of spring loaded tensioners .

[mick25]

Skypig just beat me to the post he's spot on and said it better than me .

[mudguard]

The bike is a YZ250C, without a chain tensioner. That's great advice. I thought there was more to it than having a guess of "50mm slack will do".