Hi Everyone,

I have a question for all the gurus out there in NSR land.

Has anyone tried to stoke a standard 250 crank or had new webs made.

The reason I'm asking is that the standard 250 has a bore/stroke of 54 x 54.5 which is nicely balanced and gives a generous time angle area for the stroke. This gives it a decent mid-range but also a substantial top end. By bolting on a NSR150 barrel the bore x stroke becomes 59 x 54.5, which is great for mid-range not so for top end as there is proportionally less transfer port time angle area. Therefore to rebalance the ports you need to increase the stroke, modify the height of the ports and includes a base spacer, crank case work etc.

Has anyone manage to stroke the crank successfully to give a 59mm stroke for example?

Regards
Dave