What tach do I need for my '52 International?

I used chronometric tachos for years. Vibration usually kills them. The RG250 item is rotating magnet, and the mount is beautiful, and visually correct for the era. (I'm presuming the International is a mid-fifties bike, not a garden gate model ?) I wouldn't run any OHC Norton without a tacho, it is too easy to lose track of the revs, and destroy the valuable motor. I was once offered an Inter motor for sixty Australian pounds, these days it would cost 250 times that for a replica. You would probably be stuck with buying a Summerfield manx motor anyway.
 
daveh said:
I hear figures mentioned for various singles, road and race, old and modern, that I find hard to believe..

acotrel said:
(Just had a conversation with an old Pommie friend who raced in the fifties. He says about 40bhp would be about the max for a single knocker manx.)

40hp would be with big fin head, megaphone, race magneto and race carb. And a bit of luck...?

For something with silencer, lights (magdyno) and something that idles, Nortons always claimed 32 hp for the Inter. That was supposed to good for 100 mph (just ?) if in tip top tune.
It takes about 32 hp for 100mph, average sized rider...
 
It can be surprising the difference fitting a decent race cam into a standard motor makes. You would find it develops a 'cam spot' at a few hundred revs , but still idle. I would be surprised if the late Inter had the best single knocker cam. British manufacturers didn't usually do that. A bike with a hot cam and a well designed silencer can still be fast. But I wouldn't expect you to be as silly as myself and go there .
 
Lurkinclass - do you have any pics of your Inter to share with us?
 
acotrel said:
It can be surprising the difference fitting a decent race cam into a standard motor makes. You would find it develops a 'cam spot' at a few hundred revs , but still idle. I would be surprised if the late Inter had the best single knocker cam. British manufacturers didn't usually do that. A bike with a hot cam and a well designed silencer can still be fast. But I wouldn't expect you to be as silly as myself and go there .

Repeat. All inters from the late 1940s got the (sohc) manx-type magnesium cambox with manx cams. Once the manx went dohc, they probably had a large surplus of them (sohc) in stock, and used them up in the inter....

Not heard of anyone doing a modern cam grind for an inter with muffler ? Long stroke manxs aren't very competitive against the short strokes, so if someone had found a recipe for good cams, it would be VERY obvious. And the cams being slider follower type, not so easy to find a modern performance replacement/equivalent. (Ducati desmo ??!!).
 
daveh said:
Lurkinclass - do you have any pics of your Inter to share with us?

Pics have been posted here previously - perhaps someone can find the thread ?
 
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