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1953 comp frame

Posted: Fri Nov 09, 2018 3:09 pm
by alanengineer
I have a 1953 comp frame and its been dated as a G3LC. Trouble is it has Jampots. can i just get a rigid rear frame and bolt it on? parts book show that the front frame for a comp model and a standard model have different part numbers, so does anybody know the difference.
Got the bug to build this after lots of years, just need some answers
Alan

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 4:41 pm
by Rob Harknett
A standard road model for circa 1953 will have a 5 digit number. A comp model a 4 digit number with C or CS suffix. ( I would have thought, LC would be rigid with S added for rear suspension. )

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 5:04 pm
by ajscomboman
Here's the answer that you were looking for Alan! The short answer is yes it will bolt straight on. I have (sorry) her Ladyship has a 52 LC that has had the Jampot conversion carried out. Talking to Steven Surbey it was a very common period mod seemingly, once the springers were launched everyone jumped on the conversion band wagon . If you have a genuine comp rigid rear end consider yourself very fortunate indeed as they're like hen's teeth!!

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 5:48 pm
by alanengineer
Hi, thanks for the replies
The frame has a 'c' number, and has been dated as an LC so i assume now that it has been converted.
So the question still remains, whats the difference between comp and road frames .ie why different part numbers.
And the new question is, what does a comp rear rigid frame look like/ what the difference between road and comp rigid rear ends.
Maybe, i might be digging too much of a deep hole for myself if i start to go too original. I have a rigid petrol tank!

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 6:13 pm
by Rob Harknett
There are some easy to spot differences, like fittings for seats tool boxes etc. Some can be spotted comparing pictures.
http://archives.jampot.dk/promotional/S ... _color.pdf

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 7:18 pm
by dave16mct
It might be something to do with the seat front mounting lug. On the rigids theres a stand up pillar that takes the seat nose. The tank doesn't have a cut-away. On the springer the seat fits right into the tank cut-away on the usual frame lug. Sspringer o the tank has a cut-away.
Dave.

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 9:26 pm
by alanengineer
Thanks for the link Dave, been there several times this last week comparing this and that.
Now on page two (in colour) their is somebody on a bike in the air. i want a seat like his. Its not listed. Um.

As its going, im going to build it with the bits i have and enjoy it. I have a rigid tank that i probably wont have room for and i have a road tank with cutaways for the forks. Nicely done job, not done with a swift turn left and right. Six day look alike, but it might take me longer.

Dave, on one of the images ive seen, it shows a big boss on the front frame for the single seat, but did they make changes in 53 for comp frames. i would imagine the comp shop just half inched a few rear frames from the main factory

Re: 1953 comp frame

Posted: Fri Nov 09, 2018 9:35 pm
by Rob Harknett
Getting lost on the topic now. Has Dave provided a link for something off forum, If so we cannot comment on what we have not seen.

Re: 1953 comp frame

Posted: Sat Nov 10, 2018 11:00 am
by dave16mct
No Rob, I think Alan meant your link. I'm no expert on this but I had a chat with Dudley his comp bike at our Alternative and he explained about the different tanks. Maybe ask Dudley?
Dave

Re: 1953 comp frame

Posted: Sat Nov 10, 2018 1:55 pm
by alanengineer
Hi your replies have been really useful. It wasnt Daves link as i put it, it was Robs.
I dont want to throw it together without thoughts of originality, but i do understand the way in which they were altered for specific off road tasks/upgrades.
What i have will be a good representation to a 52 G3LC. currently sourcing a comp engine case at this moment. fingers crossed.
Alan