Timing Case Assembly

greg brillus

Well Known and Active Forum User
VOC Member
The old Specialloid for racing is I think 9.5 thou, I use 10 on my road bikes, If you live in a hot place and ride hard !! How hot is it in AUS, Never been there, Cheers Bill.

Bill, It's so hot here in Oz.....we have to stop riding every 10 miles or so and park in the shade to let the tyres cool down :) .....Greg.
 

Howard

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VOC Member
The old Specialloid for racing is I think 9.5 thou, I use 10 on my road bikes, If you live in a hot place and ride hard !! How hot is it in AUS, Never been there, Cheers Bill.

I took my Comet barrel for a rebore, gave it to the machinist with the specialoid and told him 9.5 to 10 thou clearance. He looked a bit confused, then said "You mean you want it half worn out?"

H
 

greg brillus

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VOC Member
Gee If I had any of my cylinders running that sort of clearance, I would consider it well passed worn out..... Mind you, I only use modern low expansion forged pistons anyway.......Greg.
 

Howard

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VOC Member
Gee If I had any of my cylinders running that sort of clearance, I would consider it well passed worn out..... Mind you, I only use modern low expansion forged pistons anyway.......Greg.

It was my "race" engine, and it was being rebored because the last piston had siezed.

H
 

Bill Thomas

Well Known and Active Forum User
VOC Member
When I stopped racing I set a pair up at 7 thou, Playing silly beggers with a Kawawotsit on the M4, On the hottest day of the year = Nip !! Any way , It says it in the Book !! It's the rings that give you the seal, Not the pistons, My bikes have been good for Power, It was the Rider that was Rubish !! Have Fun, Bill.
 

Big Sid

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Non-VOC Member
On running the fine older Specialloid pistons . My experiance running then covers many years going all the way back to the 50s and 60s . Not only in my road bike but also in the Rattler at very high compression . And some of our Vincent motors currently run them . The Vincati has them as does Lola , our race twin . We still have a few pairs in our stock of NOS pieces .
With 9 to 1s in a street bike no closer than 5.5 thou if carefully broken in and run on the rich side on gas , and they soon are showing 6 . This will slap a bit when cold . In the drag bike 6 thou quickly opened out to 7 thou after a few runs , these were 12 . 5 to ones on methanol .
I think there is never a need for over 7 , and it will slap when cold . Sid .



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Big Sid

Well Known and Active Forum User
Non-VOC Member
Along those same lines , performance and motor head chatter if a few are interested in such stuff I can send them my of four months running series as appeared in MPH in 1962 titled " The Vincent Dragster " .


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