Another 650 SS thread !

norton bob

norton bob

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After reading about the 650 in earlier threads I would like to add some titbits that I picked up. The 1.75 journals were used in the 500 Dommyracer and in the aborted Unified twins before the SS or Manxman. I had understood there were only 2 Unified complete engines Built back in the day , AJD writes there were 6 bikes , Would like to know where she found that info. I am personally familiar with the two current reconstructions which run really well. I understood that the Lawton 650 was seized up by the works rider before delivery and had to have another barrel to replace the one with out of parralel bores . The Lawton bike was reported destroyed in the museum fire , but perhaps it just dissapeared !. I am Currently building a tribute SS producton racer so any information or photos of the Thruxton 650 bikes would be very helpfull.
 
My Lawton and Wilson Production racer 650SS replica is coming along , Already looks the part with its upswept silencers ,grey tank and Ace bars. I am not really sure how the bike was finished and kitted out in its first appearances (1962?) as there are no pictures that give much away. I think it had a black frame and primary case . There are photos of it many years later in the hands of a private owner with a repainted grey frame and lined tanks but I think this is after it went through a few hands .I think It started with a Manx type cowling and gained an Avon sports fairing later. It had Manx or Inter rearsets and a manx type seat , and a modified sls brake with big air scoops . Any additional info would be a help .
 


Freeze Frame , copy & paste . Get out the magnifying glass .

Or just emulate there satorial elegance , and it wont matter what the bike looks like .
 
Hi Matt, I have found a photo of Phill Read on the LW bike in 1963 , and the spec is as I stated above . A very basic bike ,the only special bits being manx seat ,rearsets ,exhaust lifted,ATRC tacho , manx cowl ,ace bars and tank padding. It soon lost the manual Mag and got an Automatic Advance and std K2F mag. The rear brake got some ventillation holes . A lot of attention was given to the primary chain which was the weakest link . Handling was not good untill the weight distribution was corrected by offsetting the rims to the left.
 
The 650ss as a race bike is an interesting machine. They make a great roadster but also did very well in racing, considering they received very little factory racing support and development. The Manx had received tremendous factory effort for decades and really showed that.
Nonetheless, when put up against the Manx, the 650 was pretty impressive.
For example, from Mick Woollett's book-
" Minter rode a Works 650 ( described by Hele as a tuned roadster engine in a Manx frame) at Brands where he beat Hailwood on his very fast Manx"

Glen
 
Let's not forget that Minter was known as the "King of Brands", so that would be a leg up.

Would be interesting to find out what was meant by "a tuned roadster engine". It reportedly ran the stock SS cam, so higher compression, a little sweetening of the inlets and GP carbs? Those pics are pretty grainy...
 
FWIW, racing a 650SS today I think would prove far more difficult than a Manx.

For one, there is a dwindling supply of 650 crankshafts, crankcases and cylinders.
Although not quite as bad as a 500, it is still pretty bad whereas everything is available for a Manx.

Would like to see any pictures of the Works 650.
 
I won't be converting mine to a racebike but the brief racing history is interesting.
My friend Murray Neibel was 250cc champion at Westwood and I believe at one of the Washington tracks as well. He also raced a 500 Manx Norton and a 7r AJS. Both bikes are restored to as new spec and reside in his basement motorcycle museum.
He told me that when the 650 ss based racebikes showed up at Westwood he stopped winning most everything, as he had been on the Manx. The 650s outpowered the Manx on the big hill climb and had more power out of corners while handling on par with the Manx.
The two 650s that he referred to both used Manx frames and running gear. They used 600 pistons to raise the compression for racing.

Things were just get going with the 650 when Norton started to pull back from racing and Doug Hele moved on to Triumph.

Glen
 
elefantrider said:
For one, there is a dwindling supply of 650 crankshafts, crankcases and cylinders.
Although not quite as bad as a 500, it is still pretty bad whereas everything is available for a Manx.
Click to expand...
The crank and cases can be subbed out with 750 items. The cases would require redrilling, but not out of the question for stronger aftermarket cases, but then you go down the road of the question of thru-bolts, etc. The crank has the same 89mm stroke (big ends and rods too) as the 750, so all the aftermarket Commando bottom end items are applicable.

I think where the rubber meets the road is the Manx has continued to have been developed as a no-holds-barred race bike that had not been superseded, so gets all the new super trick 4-valve heads, etc, whereas the 650 had been superseded by the Commando, and it seems like all development was more or less stopped in favor of the faster 750 starting point. There's no Full Auto 650 heads.

All kind of moot since there's not a race category I'm aware of, where a 650 would be terribly competitive these days. Fun to think about though!
 
t ingermanson said:
The crank and cases can be subbed out with 750 items. The cases would require redrilling, but not out of the question for stronger aftermarket cases, but then you go down the road of the question of thru-bolts, etc. The crank has the same 89mm stroke (big ends and rods too) as the 750, so all the aftermarket Commando bottom end items are applicable.

I think where the rubber meets the road is the Manx has continued to have been developed as a no-holds-barred race bike that had not been superseded, so gets all the new super trick 4-valve heads, etc, whereas the 650 had been superseded by the Commando, and it seems like all development was more or less stopped in favor of the faster 750 starting point. There's no Full Auto 650 heads.

All kind of moot since there's not a race category I'm aware of, where a 650 would be terribly competitive these days. Fun to think about though!
Click to expand...
I think you’re right. We’ve had articles before showing what Hele was up to with the twin and it’s a proper case of ‘what might have been’ especially as that development would have fed directly into Commando production etc!

And as you say, Manxes now are different to Manxes then. 60 rwhp is possible now. I don’t think anyone today is building 60rwhp 650 Brit twins. In fact there aren’t very many Norton twins of any size doing that !

And the market just ain’t there to do so, there are too few Norton twins racing already these days, and I’m also not aware of any 650 class for them.

The Doug Hele ‘what if’ effect is the same at Triumph, and they did keep racing, so in many ways it’s an even greater shame that more of his ideas didn’t make it into production.

No doubt the 650SS is a sweet bike though, and one that could be made even sweeter today, I do sometimes find myself wondering what a fully kitted JS 650 would be like with ultra light pistons and rods and a lighter crank etc. I think it’d be quite impressive and fun !
 
Fast Eddie said:
And as you say, Manxes now are different to Manxes then. 60 rwhp is possible now. I don’t think anyone today is building 60rwhp 650 Brit twins. In fact there aren’t very many Norton twins of any size doing that !
Click to expand...

Another 650 SS thread !

Well, there's Alp, who's good to 175mph, but then we digress...

(But if you're looking, there's what looks to be a Hunt magneto on there.)
 
My 1962 650ss is a lovely thing to ride & just to look at. It is also the most original bike I own, as I aquired it from the first owner in original trim, with the exception of Dunstall silencers. It would suit me better to have rearsets & slightly raised bars, but as it's so original I built a modified Atlas with all the goodies instead.
 
A Manx prepared today with aftermarket parts would be hard to beat.

The power potential of a 650 being within factory parts, I have never considered aftermarket barrels or cases for a 650. The small bore diameter of 68mm is probably going to be a handicap as it likely restricts breathing of a good head, IMHO. The small valves also.

Would be good to see more information and internals of the Works 650.

I have done JS rods and JE mid-dome pistons in mine. The next parts i’d consider changing is a billet, lighter flywheel and higher dome 4032 pistons and a radius cam to run the lighter-weight lifters.
 
At Bathurst in 1963, Jack Forrest beat all the 500cc Manx Nortons in an Allpowers race with a 650SS. He was a work's rider for BMW.
Small valves do not stop a motor from being powerful. Flow is a function of rate and pressure. In small inlet tracts and exhaust systems, the gas pressure is higher, and the pulses are stronger - but the port shape might be more critical.
Bob Rosenthal became an A grade rider in Australia by beating 500cc Manx Nortons with a 750cc Norton Atlas. It does not mean much. What we all need to do is race each other using single cylinder 500cc two valve motorcycles.
I have watched the best Australian riders competing with 500cc Manx Nortons. I do not kid myself that I could ever ride at that level.
A Norton Domiracer replica might get you into this :
 
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