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Rohan said:
Or sad they didn't start ten years earlier.
The 650SS
- Thread starter worntorn
- Start date
Or sad they didn't start ten years earlier.
Rohan, that is what interests me about the Domiracer, the undeveloped potential of the bike, as well as its direct connection to the 650ss. Norton had developed the Manx for about thirty years and really had nowhere left to go with it. This was just the beginning for the little twin and already it was right there, nudging up against top riders on the fully developed Manx.
From Walker's book:
"Later, at the presentation at the Villa Marina in Douglas, Tom was full of praise for the experimental Norton Twin. Although there had been a slight falling off of power during the last half lap (one piston crown having slightly touched the cylinder head), no other problem was obvious when the engine was later stripped for examination.
Tom's verdict was that steering and acceleration were superior to those of a standard Manx model, but top speed was perhaps fractionally lower. Also, the lighter weight made the front more prone to lift on full-bore bumps"
Glen
From Walker's book:
"Later, at the presentation at the Villa Marina in Douglas, Tom was full of praise for the experimental Norton Twin. Although there had been a slight falling off of power during the last half lap (one piston crown having slightly touched the cylinder head), no other problem was obvious when the engine was later stripped for examination.
Tom's verdict was that steering and acceleration were superior to those of a standard Manx model, but top speed was perhaps fractionally lower. Also, the lighter weight made the front more prone to lift on full-bore bumps"
Glen
Bernhard - you're not raining on my parade. Read my post again. I said it was new to me! You might know about it, but I was not aware they had this potential. Yes, I could buy the book, but I'm happy to learn more from Worntorn's posts.
I am intrigued by this, because during the time I have been involved in classic racing, the pukka race singles have usually had the advantage over British pushrod twins of the same capacity. Either the twins haven't been fast enough or they have been less reliable, or both, and that includes Nourish 4 valvers. Even the Honda 450 twins, which have strong motors, have not dominated the big classic events, even though they can be tuned to give greater outputs on the dyno than the replica singles. Only the replica Paton 4 valve twins seem to be able to out-perform the singles on a regular basis - at least in this part of the world. This leaves me wondering about 'what might have been' for the works Norton twins of the time.
I'm off to now to celebrate New Year's Eve, so best wishes for 2013 to all.
Dave
I am intrigued by this, because during the time I have been involved in classic racing, the pukka race singles have usually had the advantage over British pushrod twins of the same capacity. Either the twins haven't been fast enough or they have been less reliable, or both, and that includes Nourish 4 valvers. Even the Honda 450 twins, which have strong motors, have not dominated the big classic events, even though they can be tuned to give greater outputs on the dyno than the replica singles. Only the replica Paton 4 valve twins seem to be able to out-perform the singles on a regular basis - at least in this part of the world. This leaves me wondering about 'what might have been' for the works Norton twins of the time.
I'm off to now to celebrate New Year's Eve, so best wishes for 2013 to all.
Dave
Regards the potential, it was this bit that really caught my attention:
"An important step in the Domiracer's developement would have been to make suitable changes to exploit the engine's breathing potential at higher rpm. Hele was convinced that 8,000 rpm was easily within the development team's reach.
Power output of the 1961 Senior TT third-place bike was thought to be around 50 bhp, so it should have been possible to comfortably exceed the output of the fivehundred Manx, which was then producing a claimed 52 bhp.
Actually it was later discovered the TT Domiracer produced 58 BHP at 7,800 and was 'safe' to 9,000! "
Glen
"An important step in the Domiracer's developement would have been to make suitable changes to exploit the engine's breathing potential at higher rpm. Hele was convinced that 8,000 rpm was easily within the development team's reach.
Power output of the 1961 Senior TT third-place bike was thought to be around 50 bhp, so it should have been possible to comfortably exceed the output of the fivehundred Manx, which was then producing a claimed 52 bhp.
Actually it was later discovered the TT Domiracer produced 58 BHP at 7,800 and was 'safe' to 9,000! "
Glen
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Please forgive me for meddling with history, but I did some judicious editing, hope you like this :
http://www.youtube.com/watch?v=K2FWKO_8 ... e=youtu.be
http://www.youtube.com/watch?v=K2FWKO_8 ... e=youtu.be
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A claimed 58bhp doesn't mean much. It is the torque characteristics which are important. The domiracer would have had a fairly long stroke, but the manx would probably be a better package. Phillis could probably use the power to advantage on the IOM, and get decent lap times. The reality is that the IOM is only run a couple of times per year, and most guys don't race there . The 1961 manx I once rode was slower down the straights than my short stroke Triumph, but faster around any circuit. The Triumph had a top end motor, but the manx was much better to ride. You will note that when Agostini raced the MV 500-3 against the Hondas, the Hondas were more powerful, however the MV won more races , it was a much better package - torque and steering geometry - it is the way the power is delivered that matters. You need a bike which inspires confidence. If I had to choose between riding a manx or a domiracer, I know what I would be riding.
Tom Phillis would have been very familiar with the power band of the Manx single and he said the acceleration of the domiracer was greater, that seems to agrees with the 58 bhp claim.
If offered the two rides, I know what I would choose, it would be the Domiracer hands down!
The Manx is a great bike, but pretty common nowadays with Molnar and others building all these great replicas. Plus the originals are so highly prized that the survival rate is very high, like a Vincent.
I don't know how many Domiracer 500s Norton were ever built, but there cannot be all that many still in existence. Does anyone here know if the 61 IOM domiracer is still around in a Museum somewhere?
It would be wonderful to get a ride on one.
Glen
If offered the two rides, I know what I would choose, it would be the Domiracer hands down!
The Manx is a great bike, but pretty common nowadays with Molnar and others building all these great replicas. Plus the originals are so highly prized that the survival rate is very high, like a Vincent.
I don't know how many Domiracer 500s Norton were ever built, but there cannot be all that many still in existence. Does anyone here know if the 61 IOM domiracer is still around in a Museum somewhere?
It would be wonderful to get a ride on one.
Glen
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You've cropped off the right hand edge.
Triton Thrasher said:
Only on the last page...
Thanks for that.
Many of these old road tests are republished in "Norton Dominator Performance Portfolio 1949-1970" by Brooklands Books.
But not that one.
Suppose its an inopportune moment to mention that the road test of the Atlas mentioned in there, by Cycle World, produced 124 mph
(and an average of 119 mph). (They mention the 'slithery saddle'). (And show high handlebars !!)
And various tests of the Dunstall 750 Atlas produced 126 and 130 mph.
Even the Atlas Scrambler was said to be good for 111 mph - knobbly tyres and all ?!!
Maybe they just read the numbers out of the press kit ?
110 might be 95 in that case, especially withcthe vibes of the Atlas! I don't think many of those old cycle world tests involved proper testing tracks and speed trap equipment.worntorn said:
This bike was brought by Dunstall, prior to Norton’s moving down south from Bracebridge street. It was raced by Ray Prickell and became worn out. I am informed that Dunstall tried to sell it without success, and as the whole engine was virtually a one –off, it ended up in a skip, but I have been unable to confirm that last story.
Isn't that sad. Not surprising though. By the time it was worn out, it would have been yesterday's news, but still too new for collectors or museums to show interest in.
I had a good chat with Ken Molyneaux yesterday. His was the last British bike to hold the lap record at Westwood. The record was set in 63 and held for over ten years.
His bike started life as a 1955 Daytona Manx. It had alloy tanks, lightweight Manx stuff everywhere except the rims. These were steel to meet AMRA rules at the time. He raced it with good success thru the late fifties He changed the rims to Borrani alloy and in 1962 sold off the Manx 500 to pay for a new 650SS engine. He increased the compression and added a Dunstall race cam.
In his words " It would make a Short Stroke Manx or G50 look silly"
At 650cc I guess it should, and he had the record to prove it.
Glen
I had a good chat with Ken Molyneaux yesterday. His was the last British bike to hold the lap record at Westwood. The record was set in 63 and held for over ten years.
His bike started life as a 1955 Daytona Manx. It had alloy tanks, lightweight Manx stuff everywhere except the rims. These were steel to meet AMRA rules at the time. He raced it with good success thru the late fifties He changed the rims to Borrani alloy and in 1962 sold off the Manx 500 to pay for a new 650SS engine. He increased the compression and added a Dunstall race cam.
In his words " It would make a Short Stroke Manx or G50 look silly"
At 650cc I guess it should, and he had the record to prove it.
Glen
A 55 Manx would be less than competitive against even a 61 Manx.
Once Doug Hele got his hands on them, they improved, a lot.
What did they get out the 500cc Triumph that did so well at Daytona - 145 mph laps ?
And became the Daytona Model road bike, although not quite as fast in that guise...
Once Doug Hele got his hands on them, they improved, a lot.
What did they get out the 500cc Triumph that did so well at Daytona - 145 mph laps ?
And became the Daytona Model road bike, although not quite as fast in that guise...
True, Hele did a lot of work on the Manx and came up with the domiracer at the same time. I guess he didn't watch much tv or sleep in very often!
He clearly saw the domiracer as the way forward, but AMC had different ideas. Not sure if he quit or was let go, but he went down the road and did other great things. This was a real loss for the Norton motorcycle brand, but I'm thankful that AMC carried on building the SS bikes at least.
Glen
He clearly saw the domiracer as the way forward, but AMC had different ideas. Not sure if he quit or was let go, but he went down the road and did other great things. This was a real loss for the Norton motorcycle brand, but I'm thankful that AMC carried on building the SS bikes at least.
Glen
Norton moved from Bracebridge Street in the 1960s to the AMC factory at Plumstead, Helne refused to move down south, so went to work at the Triumph factory at Coventry, he ended up in their “race department” tuning their race winning 500 twins 750 triples.worntorn said:
daveh said:
Sorry I caused offence to you in any way.
I was merely pointing out what appears to you, as new information.
BTY I do not own the books or any of the books sometimes shown on this website, I obtain them from my local library, as I could spend an absolute fortune on books on subjects that I have an interest in, preferring to spend my money on what’s more important to me, the bikes
Hope you had a happy New Year celebration and didn’t get too bad a hangover :!:
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