Alignment of gearbox and play in mainshaft

I have a belt drive on my commando and was wondering how you who also uses a beltdrive align the gearbox, I find it difficult to measure.
Is it OK if you see the belt centralizing on the clutch when kicking it over several times?

I have noticed I have a "little" play in the mainshaft, if I use the belt as a lever, hope you understand what I mean, I can measure around 0,25-0,3mm movement is this something to worry about.

B.R.
Henrik

I have used an RGM belt drive for some time on a 1970 Fastback. I leave the cover off and check the belt alignment in both the hot and cold state. I also believe that the belt tracking is a good indicator of proper alignment. If you do not have the proper adjusters on both sides of the rear plates than you can have the belt get off track.
Give it a lots of slack and I have also noticed the play that you have mentioned. It appears to be normal and the clutch basket seems to wobble sometimes on mine.
This has worked well for me.
Mike 8)

I have a Norvil BD. The procedure is to install the pulley, clutch and belt and if you have a separate keeper/side plate on the front pulley leave it off for now. Rotate the engine in it's normal CCW direction a 3-4 revs and if the belt runs off to the side (comes off or starts to come off pulley) you need to check for oversize gearbox holes. The twin adjuster helps but since it only pulls at the top it can't compensate for the lower mounting hole being oversize/oval etc.
Mine has twin adjusters and the belt runs off a little but aligns itself after a few revs. There is some dust after a few thousand miles and I know I should change it but has done 20k miles like this.
If you have a front pulley with built in side plates I guess all you can do is check the parallelism of the clutch and pulley with a straight edge.

OK guys

Thanks for the advises

Have it running now

B.R.
Henrik