I've read with interest the advice in Tech Connection and in other places on the recomended 1.5" slack (measured at midpoint of the chain)in the drive chain on a 300EX. This is also what it says in the manual.
If this setting is used it usually means at past 1/2 suspension compression (bottom side) the chain will be tight with no slack. I saw a showroom new 400EX and the chain would actually stop the suspension from full travel. I have been setting the chain with the usual rider sitting on the grab bar and find it doesn't torque the output shaft on max compression but it is looser than recommended.
Are other makes models similar to this and what is the prevailing "pro/racer" solution.

 

I've found that a majority of new machines have improper chain tension. Keep in mind, chain tension should be adjusted with the rider on the bike. So obviously, this will change with different weight people.

I agree with the statement you heard, with the rider seated on the bike, you should have 1/2" to 1" (@ midpoint of chain) of slack. I would be a bit leary exceeding that, but of course it changes with each bike.

 

about 1 5/8" without the rider on it. it should be the same no matter what the rider weight.just because someone weighs more doesn't mean the chain is gonna be any tighter. with a heavier rider the suspension may sag a little more at first and make it a little tighter when you firt sit on it but once you get to 1/2 and 3/4 travel it will be the same with both rider. so just between 1 1/2 and 1 5/8 ". later,Jake