Newbie

Tom Gaynor

Well Known and Active Forum User
VOC Member
Speed and how to obtain it

Hey, good title for a book, no?
While eny fule noe that the Guzzi Gambalunga (literally "leg long") is named for its very long stroke, fewer people know what its bore and stroke were. They were 84 and 90 respectively. Of course if the Vincent had a shorter stroke, the heads wouldn't reach the UFM.........

(Some text from the previous message deleted here) ;6450]I'm heavily involved in the car tuning world and the motto there is , the head is where the power is !! Simple matter of volumetric efficiency. The head and chamber design of Vincents (post war) was probably near state of the art when introduced , but fuel quality was terrible hence the low CR's. I'm happy with some mild porting work , bigger carbs and increased CR on my Rapide as my preference is for originality and the twin has impressive power & torque even in standard spec. However , for a significant increase in power the head and chamber would need serious modification , requiring a full weld up and re-machine. Then more revs would be required and I'm not sure the standard lubrication system could cope. Also , the mag would probably run into problems with high revs so a modern igntion system would be required.[/quote]
 
Last edited by a moderator:

th4neuk

New Forum User
Non-VOC Member
Thanks for all the replies guys.

The reason why I'm asking is that I have a 1951 formula 3 racing car. You may recall the coopers as the well known name from this time.

Anyway mine is a JP racing car from scotland and it originally had a grey flash engine. The chassis and engine were separated in the late 50's early 60's and the engine is now in a VOC members comet.

As I'm unlikely to ever find a grey flash engine I was looking at maybe using a comet 500cc engine to retain the Vincent heritage of the car.

It originally ran with an Abion TT gearbox but I'm likely to use a norton box as the spares are more available.

I was asking about power as it will be running against JAP and Manx Norton engined machines and I was wondering how close I can get to them.

Obviously being a race car I have to stick to certain tuning guidelines to stay in the regs but I'll look into those in more detail.

Once again cheers for the help.

Alan
 

tonythecat

Well Known and Active Forum User
Non-VOC Member
Comet Engine

Hi Alan,
There is a shop in Newcastle, not too far from you, on the famous Westagate Road, called Classic Motorcycles tel:01912614246.

On the shop counter there is a Comet engine, it has been there for more years than I care to remember, it may be for sale? anyhow no harm in giving the guy a ring, best of luck.

Tony
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
JP

And JP is of course Joe Potts, sponsor of Bob MacIntyre, and whom I knew quite well. He was also very keen on vintage Sunbeams, particularly Model 90's. A very shy man, Joe tended to allow the light to fall on others, but in fact he was the "tuning genius". There was a time when it seemed that a large part of Glaswegian engineering talent was contributing, possibly unknowingly, to the Potts pursuit of faster bikes and cars......including a desmodromic motor.
Next to me in the paddock at Chimay was Richard Adams, who had an F3 racing car (JAP engined) in a trailer for an event elsewhere. Richard has an article in the current issue of The Classic Motorcycle (which seduced me by having a picture of the first Black Shadow, JRO 122, on its cover). Richard might well be a good start if you were looking for what can and can't be done. I have his email address and telephone number should you decide to pursue this route.
 

th4neuk

New Forum User
Non-VOC Member
Hi Guys thanks for that, I'll give the Newcastle Shop a call.

Yep it is indeed a Joe Potts Car. It is one of the early ones which was designed for either a 500 or 1000cc engine. It is the same design as the Ron Flockhart car from that period. I'm guessing if you know of the JP's then you will have come across Sean and Ben Waters? 2 Fabulous guys that are helping me with the restoration.

Cheers

Alan
 

Tnecniv Edipar

Well Known and Active Forum User
Non-VOC Member
Hi Alan,
There is a shop in Newcastle, not too far from you, on the famous Westagate Road, called Classic Motorcycles tel:01912614246.

On the shop counter there is a Comet engine, it has been there for more years than I care to remember, it may be for sale? anyhow no harm in giving the guy a ring, best of luck.

Tony

Now that is truly amazing !! I used to live up in Geordie land too !!
 

timetraveller

Well Known and Active Forum User
VOC Member
Hi Alan, you should contact Bob Culver, who manufactures many Vincent parts and who knows more about Vincent history than any one else I know of. He and his son race Vincent 500cc engined cars and as I understand it his son has been national champion in his class for several years while Bob has been up there in the top ten as well. If you do not know how to contact him then contact me privately enw07@btinternet.com and I can send you his phone number.
 
Top