750/1000 sprocket alignment

[petrolhead]

I have started a 750/1000 8V swap, it isn't straightforward.
I have made the brackets for the front, top rear and center bottom.
For the center bottom I also made some new mounts in the frame and let them weld at the neighbor/workshop.
I have kept the rear bottom mounts as a reference point.
But now the chain sprocket seems misaligned with the rear wheel sprocket.
It seems the sprocket is about half an inch to the right.
Does anyone have had the same problem ?

 

[tkent02]

They lined up straight on the two 750/1000s I've done.

 

[petrolhead]

That's good news; can you tell me how you connect the generator ?

 

[tkent02]

Three identical stator wires, which one's which doesn't matter. Same as the 750's stator.

 

[petrolhead]

Thanks, the electrics are easy this way.
My chain sprocket is 3/8 inch off center to the right from the chain guard.
I don't know how it's possible but I might buy an offset sprocket.
Also the thread from the outgoing axle is a bit damaged and the nut looks bad.
I probably try to clean up the thread and use a new nut.
It seems strange to me that the nut has some kind of lock-thread while it can work on the axle.
This seems a recipe for stripping the thread.

 

[GregT]

Don't take the chain guard as a datum. Straight edge between the sprockets is the accurate way.

What do you mean, the nut can work on the axle ? The nut retaining the sprocket is supposed to be tight against the sprocket - which doesn't move...

 

[petrolhead]

That is good advise.
I have corrected the wheel alignment and measured the difference between the sprockets with a metal ruler.
The engine sprocket is 3 mm. (0-1/8 inch) to the right compared to the rear wheel sprocket.
It does not seem much so maybe I can shim the sprocket.
The nut has worked it's way loose and the thread is damaged (at least the thread from the nut)
Are the disks beside the sprocket also supposed to be tight to the sprocket when the nut is loose ?

 

[GregT]

That is good advise.
I have corrected the wheel alignment and measured the difference between the sprockets with a metal ruler.
The engine sprocket is 3 mm. (0-1/8 inch) to the right compared to the rear wheel sprocket.
It does not seem much so maybe I can shim the sprocket.
The nut has worked it's way loose and the thread is damaged (at least the thread from the nut)
Are the disks beside the sprocket also supposed to be tight to the sprocket when the nut is loose ?

The discs - sometimes washers, sometimes sound deadening fiber washers, depending on whether it's a factory or aftermarket sprocket - should be tight when the nut is done up. It is often possible to move the sprocket position by swapping the washers around. There's no guarantee that they were in the correct place when you bought the bike....

 

[posplayr]

A straight edge against the sprocket would be great if you can do it, unfortunately unless the bike is largely disassembled you can't get a straight edge in there. An alternative I have used which I feel is adequate is to put a straight edge against the tire and check for alignment of the chain. Obviously this depends on the tire runout not being severe but this is also mitigated by the wide base over which that deviation would operate. For example even a 0.1" tire burble over 17" wheel is only (0.1/17*2)=0.011 Rad ==>.7 degrees. This is going to be way better than any laser thingy attached to the rear sprocket.

The straight edge is best if it will fit, alternatively here is a picture of construction level against the rear tire showing alignment of the level and chain.