Discussion in 'Norton Commando Motorcycles (Classic)' started by acotrel, Dec 11, 2015.
Here is an interesting Norton :
Roy is a facinating man, with some great stories. He was part of the original build with Ken who appears to have been a natural on a bike. Really fast on the track & a real biker who rode his bike on the Queens highway.
Since Mike, Kens brother restored it, its been seen at lots of circuits & is beautifully restored but also such an original design. With its clothes on you would think, Seeley Mk3.
Must admit I did not know that 5 were built. Just remember Roy saying the 750's never caused problems but the 850 grunt pulled them apart. Thats how I met Roy. My Seeley MK3 road bike broke its frame & he advised me to re tube it. He also advised me to keep an eye on my Rickman frames as they were nickel plated like the Redfern bike.
If you have a look at the beautiful Ducati Pantha 600 F2 race bikes from the TT & you will be looking at Roys work. The bit I like is that he has managed to aquire a fair few of them back into his fold. If you fancied a Redfern Norton, you could not be dealing with a better guy.
Kens story was written up in Classic Racer a few years ago. The man was a talent & his end makes sad reading but as a biker its almost story book.
A good friend of mine has bought and restored one here in Belgium. Lovely bike!
And it seems there is a second one in the country...
I'm very short of cash these days, however I have a two stroke project I can sell to finance another commando based racer. A second Seeley frame would be really nice, however there does not seem to be many other viable options which would cost less.
I saw one of them at Gedinne, probably 2 1/2 years ago now...
Does Roy Thersby still make that frame ?
Hello yes is the answer. I am making 5 frames. The frame will be the modified version of the oil in frame version raced by Ken and later by mike redfern. The original frame although handled very well had its little problems. I have complete new front ends to fit the frame with disk brake and the original seat and fiberglass fairings. Please contact me for further details.
How lovely to see you on here!
Any chance you could post up some photographs? Would love to see the detail in the oil in frame.
all the best Chris
Yes, it would be great to see some better photo's.
Hello thank you for the add to the site. I have started on the 3rd frame now. Number 1 was a prototype from the jig made from the original Redfern frame. The original frame although good wasnt in line and Ken and the other riders rode round the problem. The 2nd one Bert Robinson now owns required the seat height raising as knee damage stopped him sitting correctly on the lower seat. He is happy with what we made for him. Well he hasnt said untoward about the frame. The 3rd and the 1st to be made available for sale in now in the jig with the head stock and oil tube and a few other joints assembled in the tube end. At this point i have to make the engine plates before assembling further any seat / rear downtubes to ensure all lines up. For anyone wishing to fit different sized engines i allowed space on the cylinder head engine mount to cover all engines from 500 to 850cc. I will try and post a picture from my fone. Not sure how to accomplish this but if no picture arrives.. i am trying. Also shortly after Ken and Kieth Jeal made the frame, Ken made a drawing for a square section swing arm but never produced it. Kens idea was to fold up flat steel plate into square and assemble it that way. The steel and folding process would not have been strong enough. The square section steel tube now supplied is adequate to cover the wider tyres available and rigid to stop distortion, i may make a little addition just to give it that bit extra. I am keeping it twin shock, as Hagon makes some good rebuildable shocks. The manx front forks i got from a midlands dealer. (He wont be supplying any more.)
I am interested to learn what kind of tubing you employ - 4130 seamless tubes perhaps? And for the backbone tube...? Do you subject finished frames to PWHT as well?
Also, I am interested to know how you qualify your frames for powerful disc brakes. Do you have to satisfy an approval scheme in order to sell frames to the public, even if for racing only?
Roy, would you possibly quote an approximate price for one of your frames ? - within 10% would be OK. I once looked at one of Barbour of Attleborough's frames out of the UK. The cost was a bit prohibitive. The beauty of what you are making is that it has a history. I think a Mk2 Seeley frame would have to cost over $5000 these days.
Thersby. Would you please post a side-on picture of the frame ? Is it the ''drain-pipe Norton' or different ?
If you have trouble posting pics email them to me and i will post them here for you accessnorton @ gmail
Jeez Al, the drain pipe was Paul Dunstall, didn't we cover that somewhere?
Chris said some where earlier the Redfern frame is reminiscent of a Seeley, and that is what it looks most like to me. Roy can probably clarify who did what, when and why!
I thought the Drainpipe was a New Zealand frame. From the photo it looks like the Thersby frame has a large spine like an Egli. But I can never figure out how the rear subframes attach to it, if it is like that..
Dusntall drainpipe pictures. First one from Dunstall tuning manual, other two posted previously on forum, but I don't know by whom.
Which is the most cost-effective frame for a racing commando ? I was looking at a video of a Ron North framed Commando yesterday. - Looks good. And I've seen pictures of an Egli-Commando. I think the re-sale value of a Mk2 Seeley framed Commando would be higher than most others. When you think about it, you can build a lot of motorcycle for $10,000. But if you are doing that, you need to get something back if you sell it.
I wonder why anyone would consider using a frame design for racing which is clearly inferior to later designs wrt. torsional stiffness. The Redfern design relies on torsional stiffness and to lesser extent, small tubing bending stiffness. The torsional stiffness of the spine tube attching to a vertical seat post tube isn't great. Norton's monocoque design had an immensely high torsional rigidity (~ enclosed box section area) but the engine wasn't service friendly. The Rob North design provides great overall torsional stiffness as it relies both on section torsional stiffness and section bending stiffness. The best designs today employs heavily braced 3D framwork designs using small diameter tubes and having a short distance between headstock and rear fork supports (so-called trellis design). This frame concept relies on tube section high tensile strength mainly. It also provides excellent transverse bending strength and low weight. As we know Norton's racing team made the same discovery but by then the engine was not competitive.
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