Sprockets missaligned

[Bevel bob]

I notice wear on the inside face of the gearbox sprocket , Also the chain drive sounds noisy.Moving the sprocket away from the box does not appear to be an option as the sprocket already overhangs the shaft. I'm left with moving the wheel over towards the brake side,The rear fork has spare clearance so a spacer on the sprocket side seems the way to go plus move the rim on the hub to align with the front ,Am i on the right track here?.

[double diamond]

If you've verified that there is a sprocket alignment issue (maybe attach some sort of straightedge to the sprockets) and that the chain adjusters have the wheel properly centered and in line with the front wheel (and that you don't have a bent swingarm or frame), then I'd say you're on the right track. Matt

[Bevel bob]

I think i may have found the problem. My gearbox sprocket is flat (no shoulder) and is spaced with an aluminium sleeve/spacer, which is not good for support and may be to the wrong dimensions. What was the orriginal sprocket combination for a 250 mark3 narrow case?, same as Mach1? , Lower gearing may be more suitable for the lanes and traffic.Currently running 17/42, seems a bit low, thinking of trying 18/42 ,I think standard is 18/40 which is very high but may be beneficial in that 4th gear would get used mostly(saving the weak 5th from wear).Does anyone else run the high gearing?.