Norton Exhaust Thread Chaser

[motorson]

The two bolt looking ones are the Left Hand pedal shafts from bicycles. I hardened them really hard before cutting the groves with the cut off wheel. I tried to harden the Norton exhaust nut but it wouldn't get any harder. (must not have much carbon in the steel) It helps that I have a single thread thread-file my grandfather used to own.

 

[rvich]

I'm not surprised that the exhaust ring wouldn't harden very well. I didn't know that the bicycle pedal shafts have the same thread count and profile. Police will be baffled when left side pedals start disappearing across three continents.

Russ

 

[motorson]

The photos of the bicycle pedal shaft thread chasers are just to illustrate the idea. They are unmodified left hand threads and only used to chase the threads in the bicycle crank arm that has left hand threads. (The right hand tap for the other side is not hard to find for sale commercially.)

The Norton exhaust nut with the slots gound in it straightens out mildly messed up threads quite well so I just thought I'd give away the idea for everyone’s use or amusement.
Cheers, Dan.

 

[cjandme]

Thanks for the Idea, I do have an 850 head on my project bike where the left hand side exhaust port threads are messed up. But I doubt that there is enough material remaining in the ports for me to chase and clean up. I'll have it repaired when the time comes. Our forum's own comonoz (did I spell that right), will do them very reasonably using the new bronze aluminum material for his inserts. Cj

 

[lcrken]

Thanks for the Idea, I do have an 850 head on my project bike where the left hand side exhaust port threads are messed up. But I doubt that there is enough material remaining in the ports for me to chase and clean up. I'll have it repaired when the time comes. Our forum's own comonoz (did I spell that right), will do them very reasonably using the new bronze aluminum material for his inserts. Cj

That would be comnoz, our own Jim Comstock.

Ken

 

[stockie2]

Just curious what TPI where your, mine are 12 and I believe the std is 14TPI?

Cheers Richard

 

[motorson]

The stock Norton Commando exhaust thread is 1 15/16 or 1.9375 inches x 14tpi. There is a tap available for sale for US $134 at the link below.
If mine needed more than just chasing I would look into sending the head to some one like Comnoz for a complete insert job. I can't imagine an insert with a different thread count than the stock Commando thread though.

http://drillsandcutters.com/qualtechdwt ... ecial.aspx