I have installed new sprockets and a new chain today.. (D.I.D VX2 520)
In the manual it says that the weel should be elevated from the ground when measuring the chain slack.. We did set the chain slack to approx 40-45mm when the back wheel was elevated..

When I tried the bike and sat on it the chain felt very tense, almost no slack at all.. So we loosened the chain again and got more slack.. Now the slack is pretty good when I sit on the bike..

But what is the best way to measure (and adjust) the slack? Is it better to measure the slack when the swingarm is compressed a little bit (the usual when riding the bike..) or should it be quite slack when the suspension isn't compressed and pretty tense when compressed?

We also tried to put first gear in and then move the wheel a little bit backwards so the above part of the chain was quite tense and the lower part was quite loose.. But what is right?

Please guide me!

Thanks in advance!

Sounds like you're doing things about right.

The chain slack will decrease as the suspension compresses and the swingarm comes in line with the gearbox sprocket shaft.

I do exactly what you did - check to get the slack about right with suspension fully extended (on centre stand), then sit on the bike and check it's not too tight and adjust if necessary. In a way, it's all about what feels right, you pick it up more easily as you get used to the bike.

Bear in mind the new chain will loosen (stretch) a bit after you've ridden it a couple of times and you'' have to keep readjusting for a few hundred miles. So I wouldn't waste too much time trying to get it perfect now - it will all change as soon as you've ridden it!

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Thanks, good to hear
I will keep an eye on the chain before every ride.
I bought an 46t sprocket to the rear and I was needing a 112 chain for that when I read that in Off the road's table for sprocket and chain size..

But the wheel is quite a bit back on the swing arm now.. I think a 110 chain had been to tense but a 112 chain feels quite long.. Not too long, but a 111 chain had been perfect (if that existed..)

When the chain is stretched quite a bit more I think I will remove 2 links from it.. Will probably be perfect..

After my original chain jumped the rear sprocket, (expensive!) I'm paranoid about a chain too slack.

I adjust mine by slowly tightening it up, test riding it until I get the whine of a too tight chain and then slacken it off 2 sides of the adjustment nut. As already said the tightest point is when the centres of the front sprocket, swinging arm pivot bolt and rear axle are all in line. So you could disconnect the rear shock and move the wheel through this point and check the chain there.

With all my bikes ...
I put a tie down from the swing arm to
the grap handle..pull the back down till
the engine sprocket/ swing arm pivot &
axle are in line... adjust it to have slight
slack at that point..

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Harley Davidson..
The easyest way to turn gasoline into noise with out the side efect of horse power...

Thanks! I did kinda like that when when I adjusted it this time. Seems to work good