[Fot] TR3 timing cover bolt threads

[Bill Babcock]

I know I'm a terrible person, but i always just tap these things out  
to the next pipe tap size. the notion of a non-tapered pipe thread in  
cast iron just doesn't make that much sense to me.

Of course I once converted a 1958 BSA A-10 to metric, but that's a  
different story. I bet whoever has that bike today wonders WTF.

On Feb 2, 2009, at 7:48 PM, WILLIAM TOBIN wrote:

>  Hi Greg: I ran into this on my TR6.
>  The difference between the British 3/8 pipe and 3/8 American  
> Standard Pipe
> is very small. 1 thread per inch and 0,010 inch diameter.
>  I just took a 3/8 NPT tap and tapped the threads in the housing to
> American Standard tapered pipe threads. Very easy, Now the Auto Meter
> adapter screws right into the housing. Before that I brazed an Auto  
> Meter
> adapter to an original temp fitting; not pretty but worked.
>  I think the part number is 1074-3/8 NPT for the adapter.