• Welcome to the website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Hon. Editor and Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this website.

    If you have previously registered to use this forum, you should log in now. CLICK HERE.

    If you have never registered to use this website before, please CLICK HERE.

Misc: Everything Else Standard Comet Special


Oldhaven

Well Known and Active Website User
VOC Member
I am underway on what will likely be my last motorcycle project and two weeks ago a set of 1951 Comet cases and covers arrived from Australia. The Comet was originally delivered to Liverpool, so they have traveled a bit. Mal Hewitt bought them several years ago thinking he would build a Comet special, but his time has been otherwise occupied it seems. I will probably use this new thread to ask a few questions, and here is the first one. The crankcases at one time passed through the Horner's shop for some repair work on the main bearing bores, but I am puzzled by the spigots for the push rod tubes. They are threaded. Does this modification ring a bell for anyone? Perhaps some clever attempt at sealing?

P1050079.JPG P1050104.JPG
 

Bill Thomas

Well Known and Active Website User
VOC Member
I am underway on what will likely be my last motorcycle project and two weeks ago a set of 1951 Comet cases and covers arrived from Australia. The Comet was originally delivered to Liverpool, so they have traveled a bit. Mal Hewitt bought them several years ago thinking he would build a Comet special, but his time has been otherwise occupied it seems. I will probably use this new thread to ask a few questions, and here is the first one. The crankcases at one time passed through the Horner's shop for some repair work on the main bearing bores, but I am puzzled by the spigots for the push rod tubes. They are threaded. Does this modification ring a bell for anyone? Perhaps some clever attempt at sealing?

View attachment 16213 View attachment 16214
Can't help you Ron, But does a standard pushrod tube seal fit what you have, In which case you may be able to drill the threads out and go back to standard ?.
Good Luck , Bill.
 

davidd

Well Known and Active Website User
VOC Member
Robert Watson used an O-ring. It would be interesting to know if he still uses it. It was a lovely job of cutting an O-ring in an aluminum tube and pressing it into the case. I thought it was brilliant because you could move the push rod tube up and down without yanking the seal out of place, which can happen with the stock set up.

David
 

timetraveller

Well Known and Active Website User
VOC Member
It looks to me as though they designed something which would go round the pushrod tube and compress an 'o' ring when it was tightened down. I can see that this would make a better seal than the original set up if there is lots of crank case pressure but for normal use the original set up works well if the tubes and the seal housings are in good order.
 

Oldhaven

Well Known and Active Website User
VOC Member
I think I have figured out what the modification is. I mentioned that the cases had been at the Horners for repairs, so I took a look at pictures here of one of their other projects and found this. The thread looks like a metric 22mm and the screwed or pressed in fittings in the cases of the Rapide must have some sort of seal like TT mentions above. I can almost see an o-ring or oil seal if I zoom in. they must have been experimenting with something like that. I wonder if the slight differences in angles of the tubes is compensated for. It also looks like the upper gland nut has been modified.

push rod tubes (Large).jpg
 

robin

Well Known and Active Website User
VOC Member
This is a well known mod, if done correctly, you use a threaded gland nut similar to an ET127 and an 'O' ring. No more leaks.
Robin
 

vibrac

Well Known and Active Website User
VOC Member
seven years of advice is sitting on the little search button above
SEALING PUSHROD TUBES
2015
Leaking Push Rod Tubes
2012
Push rod Tubes
2010
 

Cyborg

Well Known and Active Website User
VOC Member
What's your plan for a frame, forks, brakes, etc? I have a set of Comet cases and have been mulling over what to do with them. One thought is a spine frame and some Japanese forks and brakes. Would that get me drummed out of the VOC?
 

vibrac

Well Known and Active Website User
VOC Member
What's your plan for a frame, forks, brakes, etc? I have a set of Comet cases and have been mulling over what to do with them. One thought is a spine frame and some Japanese forks and brakes. Would that get me drummed out of the VOC?
It didnt seem to affect the standing of a certain Swiss Gentleman:) of course if you are from an EU country you should be more worried about trying to get it registered rather than the aprobation of a few Vincent owners, but then again a certain French Gentleman seems to manage it....:cool:
 

Cyborg

Well Known and Active Website User
VOC Member
The frame has the necessary paperwork. It's not my first choice, but it's the path of least resistance from a registration and budget point of view. Although having said that.... I'm in the process of registering an orphan bike now and other than being annoying and time consuming it appears to be more or less straight forward (so far). An upside to living in the colonies and being 4,362.7 km from the nation's capital perhaps.
 

Oldhaven

Well Known and Active Website User
VOC Member
What's your plan for a frame, forks, brakes, etc? I have a set of Comet cases and have been mulling over whsat to do with them. One thought is a spine frame and some Japanese forks and brakes. Would that get me drummed out of the VOC?
With what you are working on now I don't think you will be drummed out anytime soon.

My plan is a 600cc Comet using Terry's latest stuff in and on the engine. Standard stroke flywheel. A Commando box, they are all here now. Newby Clutch and belt to arrive anytime now. David Dunfey has agreed to sell me one of the tubular spine monoshock frames he is doing. It can use the Works Performance coil over on the rear and it will be set up for a 750 GSX-R front end and brakes. I will start with a standard Suzuki front wheel and for sure the brakes and rotors, but I have a few ideas and I am not sure about rear wheel and brakes quite yet. The japanese stuff is really inexpensive on the Bay. I am selling my '75 Ducati 750 GT plus a bunch of stuff from a lifetime of Land Rovers to finance this all. So there you have it....2017 version of the Standard Comet Special and I will be busy this fall and winter. For now I need to get the oil changed and do a spring once over on the Rapide. I hope everyone had a great Easter. It got to 84F here today, but will be back in the 40's and 50's next week. Good riding weather
 

Cyborg

Well Known and Active Website User
VOC Member
When you say standard stroke, are you going to use a crank from Terry or the factory one you have in the photo?
For my brakes, wheels and forks, I'm tempted to use the internal disc CBX550 stuff that has been sitting in my "someday I'll use that" pile since the early 80's. I have a lay down Norton box, but for the sake of oil retention, I think I will try and find a Commando box as well. I shouldn't even be thinking about it at this point. Must try and stay on track... spent some quality time with my favourite bastard file today. Fitting the rear fender flap.
 

A_HRD

Well Known and Active Website User
VOC Member
"Standard" Comet "Special", isn't that an oxymoron?
No, of course it's not! I own one! :p

Check your Vincent history. From memory about 40 "Comet Specials" left the HRD-Vincent factory around 1935-1937. They were also designated TTC. They were basically road-going Series A Comets but fitted with slightly de-tuned TT Replica racing engines with bronze heads, TT Carbs, TT Forks, TT Brakes, etc. Customers could tweak the spec as they wished, but when each left the factory it was a factory standard "Comet Special". :cool:

http://thevincent.com/vinprod.html

Peter B
Bristol, UK.
TTC 20 - Comet Special.
 

Bill Thomas

Well Known and Active Website User
VOC Member
No, of course it's not! I own one! :p

Check your Vincent history. From memory about 40 "Comet Specials" left the HRD-Vincent factory around 1935-1937. They were also designated TTC. They were basically road-going Series A Comets but fitted with slightly de-tuned TT Replica racing engines with bronze heads, TT Carbs, TT Forks, TT Brakes, etc. Customers could tweak the spec as they wished, but when each left the factory it was a factory standard "Comet Special". :cool:

http://thevincent.com/vinprod.html

Peter B
Bristol, UK.
TTC 20 - Comet Special.
They had Funny Pushrod Tubes Also !!. Cheers Bill.
 

Oldhaven

Well Known and Active Website User
VOC Member
When you say standard stroke, are you going to use a crank from Terry or the factory one you have in the photo?
.
I have a new one that arrived from Australia this last Friday. The one that came with the cases looks OK and has zero side and end play, but I have not checked it for runout. It looks to be either all over polished or perhaps even chromed, hard to tell. I decided to go with new everywhere except for a few necessary frame attachment parts since there was nothing in or on the cases except the magneto studs and I could match the flywheel and the top end from the same maker. I will be keeping the VOC spares company and Coventry Spares busy. It is times like this that makes me realize how fortunate we are with our choice of machine, since if I had decided to rebuild my old 750 GT I would have had considerable difficulty and much more expense than doing this Comet special basically from scratch. I have to agree with Bill's advice to only keep Vincents so you can swap things around. I also feel I am not doing anything sacreligious with the Comet cases since they have had considerable repair work done and would never have become an original bike again.

Here is one of David's UFM's on a twin. There are no rear seat shock mount tubes as on a normal Egli type frame, and the seat can be cantilevered. The RFM is more Vincent like but it will be used with a coil over:

DSCN1051.JPG
 

Top