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Hi,
Can someone please confirm the thread size on the end of the crank on my '74 Interpol.
I believe from Access Norton forum 5/8'' x 20 TPI BSC ?
Reason I ask, so I can get a bolt that will screw into the nut that holds the rota to the crank and then with a few nuts on that bolt, hold a degree disk to check the advance timing for the Boyer.
Thanks - Paul.
Hello Paul - I usually add a…
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The Thread is 5/8 UNF 20 TPI…
The Thread is 5/8 UNF 20 TPI, same thread angle as cycle and same TPI but the peaks and troughs are not the same, you may get them binding part way on if mixed but will be good enough for what you are planning. Reason I know is I made a couple of extended nuts and bought the tap to do the internal thread. The original nut has circles stamped on the hex, this is the normal stamp for UNF.
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Hello Paul - I usually add a few washers outboard of the rotor on the crankshaft and then fit the degree disc between another couple of washers on sleeve nut and gently tighten it all up. The washers stop the degree disc fouling on the stator. I then fasten my marker under one of the side cylinder nuts. You didn't say whether your Interpol is 750 or 850. If it's an 850 the marker needle will have to mount on a forward nut. You're correct about the thread-form and size.