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Singles / Re: B31 crankshaft/ cushdrive woes
« on: 09 February, 2017, 08:17:18 »
Thanks John, if you are correct that would explain the odd size and if I could find any sort of nut with that thread then I'd be able to make a retaining nut and save buying a new crankshaft, which would be a great relief given the time I've spent building this one.
I'll start searching for a nut or a tap before splashing out on a replacement shaft.

Singles / Re: B31 crankshaft/ cushdrive woes
« on: 06 February, 2017, 12:11:12 »
Thanks Andy, I'm a couple of hours away in North Yorkshire so postal costs will need to be considered. I've just bought a new big end so it wouldn't matter if I got a shaft with a knackered big end. Let me check prices and costs.

Singles / Re: B31 crankshaft/ cushdrive woes
« on: 05 February, 2017, 17:35:28 »
Thanks one and all for the comments. I've just been out to check my measurements and I can confirm that the shaft thread is 22 tpi and 11/16" and measured my pals which is 20 tpi and 3/4". It beats me as to why mine would be an odd size.
I don't have access to the type of equipment to make a suitable nut, and I haven't found a listing for one, so I guess I'll simplest solution would be a replacement crankshaft, which hurts a bit having spent a lot of time truing mine.
I could be interested in yours Andy, what were you thinking, and where are you based?

Singles / Re: B31 crankshaft/ cushdrive woes
« on: 03 February, 2017, 19:33:48 »
Hi Arthur
It's a box of bits I'm afraid. Shaft thread seems to be 22 tpi, if I'm reading my gauge correctly. I had thought if all else fails I'd find a nut and weld a big washer to it, but as yet, I can't find any reference to 11/16 22tpi.

Singles / B31 crankshaft/ cushdrive woes
« on: 03 February, 2017, 14:13:26 »
I'm building a B31 from parts, I have a 2 lobe cushdrive but not the retaining nut/collar to screw it to my crankshaft. The problem is I've discovered that threads where it screws on, measure 11/16" on my crankshaft, whereas my pals crankshaft measure 3/4" (Draganfly list this size). Does anybody have any thoughts on why my crankshaft thread is a different size? It has the 66 610 casting stamp which I believe is normal, and it fits into the bearings and cases fine. Is there a smaller size retaining nut/collar?
I could look for a complete cushdrive but I'll still have o find a nut for the smaller crank thread whichever cushdrive I use.
All suggestions welcome.

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