PT: Exhaust Vincent Head Exhaust Threads

Roslyn

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Non-VOC Member
I am soon to move my bike into the shed ready to try and fix it and one of the things that need doing is the threads on both heads and any advice as to where to to get them repaired as it will the first time i will have stripped a Vincent engine down by my self without any sort of support.
 

vibrac

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Rofor engineering in Milton Keynes (Roger Forsythe) always did mine he even did one on my Comet Trials outfit still on the trailer
 

Roslyn

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Rofor engineering in Milton Keynes (Roger Forsythe) always did mine he even did one on my Comet Trials outfit still on the trailer
When you had them done did you have to strip the heads down before like remove the valves and rockers?
 

vibrac

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VOC Member
No as I say it was on the trailer (exhaust pipe off) and involved an insert and a modified nut normally however you do it in a strip down
 

Bill Thomas

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How bad is the thread ?, Only the nuts vary a lot in size, Maybe a slightly bigger nut would get you out of trouble ?. Cheers Bill.
 

Monkeypants

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I repaired minor damage to one of these by scraping the threads with an appropriate tpi threading tap. This enlarged things slightly so larger exhaust roses were required. As Bill mentions, there are many variations in size for these.

That repair has been ok for about 60,000 miles or so including a couple of careful exhaust off and on agains.

Glen
 

Bill Thomas

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I saw the other day, Albervin, Say use 2 washers, I would not,
It leaves less thread to grip, We need all the thread we can get !.
I think I used a thread chaser, To clean the threads, They are cheap to buy,
Also make sure the pipe flange is square to the inside hole, To give max' thread contact,
Never use a spanner till you are sure it's in square.
 

vibrac

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VOC Member
I put this job with the positioning of push rod ends in rockers as the job I least like doing on a Vin. I find turning backwards helps get the nut square (and some coppa slip). The time to tighten fully is after the first run when engine is hot
Its a job not to do in a hurry which is why on the racer we have stub pipes and springs
 
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