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Discussion Starter #1
The previous owner of my '68 Bonneville has put some questionable handlebar bolts on it and now the chrome is starting to peel. What size were the original bolts? How much "neck" did they have?

I've tried measuring the one I took off but the numbers are a good mix of metric and unified. The bolt is not 1 inch long but I've counted 8-9 threads per half inch.

https://www.dropbox.com/s/vxrwusgu77j6nds/2012-10-10 14.38.02.jpg

Thanks :)
 

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Discussion Starter #3
Great document! But I'm not sure how to read it :) It says the bolts I need are UNF 5/16"-24x1-1/8" HANDLEBAR CAP.
That doesn't seem to match the measurements I've got?
5/16" is the headsize, right? I'm measuring 16.8 mm (10.5/16") on my bolt :)
 

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5/16" is the shank size,and approximately the major diameter of the thread.
The hexagon size on a 5/16" UNF bolt is 1/2" A.F.
 

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Discussion Starter #5
I took the bolt to a machine shop and they measured it. Turns out the PO somehow thought it was a good idea to use a M10x1.5 bolt and retap the hole in the clamp :confused:
 

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I always shudder when some bright spark buys a Triumph and tries to convert every thread to metric.

FFS buy a honda
 
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