The 650SS

acotrel · Dec 29, 2012

I rode hot 650cc Triumph twins for years , I've also ridden a good 1961 model Manx. I defy anyone to beat me around our local circuit with a near standard Triumph 650, if I was on the Manx. The Manx is actually a fantastic package, - goes, stops and handles. I've had the experience, and now I know why our old top liners loved them so much - very hard to beat. As for the 500 domiracer - you used to rebuild a manx once per season. When the domiracer slowed when Phillis was riding it on the IOM, perhaps the pushrods had become shorter ?

Rohan · Dec 29, 2012

These accounts remind of the story of Bob McIntyre in the 1959 Junior TT was it ? - on a privately entered AJS 7R, he harried the MV Augustas for most of the race (on paper, they should have been streets ahead), until his cam chain broke on the last lap (7R's never broke cam chains !!). And in the Ulster Junior GP of 1960, Alan Shephard on a privately entered 7R harried John Surtees on the MV 350 multi all the way. So much so that MV protested the 7R, and insisted it be measured (in case it was a 500cc). It was exactly a 349cc.

Maybe the rider has something to do with it.... ??
We digress from the 650SS a little here but.

worntorn · Dec 29, 2012

It would be interesting to see if any Goldies were entered in the production races won by the 650SS. Will do some research.

Glen

worntorn · Dec 29, 2012

Had an interesting chat today with Murray Neibel, owner of Modern motorcycling. Murray is an oldtime racer. He pretty much dominated the 250 class with his x6 Suzuki back in the late sixties. He was also a contender on his 500 Manx in the 500 division.
He also has a 350 Manx and an AJS 7r.
He remembers the first 650 ss Norton that ran at Westwood in 62. A friend purchased it new, broke it in then got it ready for racing. This involved nothing more than removing the headlight and swapping the cigar mufflers for some reverse cone megas.
It laid waste to all the Manxes and G 50s running at Westwood at that time. Westwood is a small, tight mountain track, with a decent straight, a hairpin or two and 900 ft of vertical rise in a 2 mile track.

Another bit of SS trivia- the 650 ss that won the Thruxton in 1962 (Brian Setchell and Phil Read) did so at a higher average speed than the 1970 winner, Peter Williams & friend on a 750 Commando.

Glen

daveh · Dec 30, 2012

worntorn said:
Had an interesting chat today with Murray Neibel, owner of Modern motorcycling. Murray is an oldtime racer. He pretty much dominated the 250 class with his x6 Suzuki back in the late sixties. He was also a contender on his 500 Manx in the 500 division.
He also has a 350 Manx and an AJS 7r.
He remembers the first 650 ss Norton that ran at Westwood in 62. A friend purchased it new, broke it in then got it ready for racing. This involved nothing more than removing the headlight and swapping the cigar mufflers for some reverse cone megas.
It laid waste to all the Manxes and G 50s running at Westwood at that time. Westwood is a small, tight mountain track, with a decent straight, a hairpin or two and 900 ft of vertical rise in a 2 mile track.

Another bit of SS trivia- the 650 ss that won the Thruxton in 1962 (Brian Setchell and Phil Read) did so at a higher average speed than the 1970 winner, Peter Williams & friend on a 750 Commando.

Glen

So the extra 150cc and wider spread of usable power would have given the twin an advantage against the racing singles on that circuit? When classic racing took off in Ireland in the 1980s, there were some original Manxes and G50s on the grid, and if the circuit was tight, I could keep with them. (I had a not very competitive Ducati 450 at the time). The 4 speed close ratio 'boxes on the Manxes and G50s meant that they took time to get up to speed after exiting slow corners. The longer the straights, the more likely they were to come by me.

grandpaul · Dec 30, 2012

Rohan said:
Maybe the rider has something to do with it??

YAHTZEE!

acotrel · Dec 30, 2012

In about 1961 I watched Tom Phillis trounce all of our top guys in the Australian TT at Phillip Island. He would not have been hanging around with the Domiracer at the IOM. But all things considered the twin motor in the featherbed frame can never be as good as the single it was designed for. THe manx engine always sits lower and further forward, and it is a much more developed engine anyway. If you want to see a highly developed twin, have a look at the Paton. The Norton twin motor is surprisingly good for what it is, but it is not in the same league as the Paton or even the Laverda twins. I suggest that a Montjuich 500 would cream the domiracer. The domiracer would have been difficult to develop. I understand that Norton sent one of their guys to buy a Triumph race cam so they could copy it, but they would have found it very difficult to optimise the timings without being able to move the exhaust and inlet cams independently. A better option would have been a Triumph bottom end with a Norton style cylinder head. The Matchless G45 might have been an even better starting point. Some of our guys have fitted XS2 Yamaha roller bearing cranks into those old motors which have the centre bearing.

daveh · Dec 30, 2012

worntorn said:
the 650 ss that won the Thruxton in 1962 (Brian Setchell and Phil Read) did so at a higher average speed than the 1970 winner, Peter Williams & friend on a 750 Commando.

Here's a clip of this race from Pathe News. Unfortunately, there's no sound: http://www.britishpathe.com/video/thrux ... cycle-race

coleighf · Dec 30, 2012

Fascinated by all of this. I had my first 650SS in 1965, a 1962 Bracebridge street bike. I still have one now, although it was originally a 1961 99 which I did a full conversion to 650SS in 1970. The comments about "barrels bursting" probably refers to the tendency of the early type con-rods to break at high rpm or after high mileage, cured in 1964 by the introduction of the oval web rods which later went all the way to the final 850 Commando. I still have the Bruce Main Smith road test reports from 1962 in which he got a mean of two ways of 111+ and a best in one direction of 118. 0 to60 was 6 seconds. Interestingly in 1961 he tested the 88S with the earlier head and siamese pipes and got a mean of 106 with best one way of 111. Apart from the early con-rod issue, the main weakness of the 650 motor was frequently fairly limited main bearing life, the complete cure for this being the fitting of Superblend bearings, the same being true for the Atlas and the early Commandos.

acotrel · Dec 30, 2012

I think I should buy myself an Ariel Leader. It passed the Norton going about 40 mph faster !

Rohan · Dec 30, 2012

worntorn said:
He remembers the first 650 ss Norton that ran at Westwood in 62. A friend purchased it new, broke it in then got it ready for racing. This involved nothing more than removing the headlight and swapping the cigar mufflers for some reverse cone megas.

And hopefully changed jetting - or a few burnt valves and pistons ? :mrgreen: :mrgreen:

worntorn said:
It laid waste to all the Manxes and G 50s running at Westwood at that time. Westwood is a small, tight mountain track, with a decent straight, a hairpin or two and 900 ft of vertical rise in a 2 mile track.

Another bit of SS trivia- the 650 ss that won the Thruxton in 1962 (Brian Setchell and Phil Read) did so at a higher average speed than the 1970 winner, Peter Williams & friend on a 750 Commando.

I'd find that a little odd - a roadbike with a claimed 50hp could do a race bike with a genuine 50 hp. ?
But obviously I wasn't there. Did they gear down for the short circuit....

I seem to recall the first time Peter Williams raced a Commando in F750 at the IoM, he lapped slower than a (500cc) Manx had, 10 years earlier. ?

Rohan · Dec 30, 2012

acotrel said:
I think I should buy myself an Ariel Leader. It passed the Norton going about 40 mph faster !

And you wonder why people don't take you seriously...... ???

Triton Thrasher · Dec 30, 2012

Rohan said:
acotrel said:

I think I should buy myself an Ariel Leader. It passed the Norton going about 40 mph faster !

Click to expand...

And you wonder why people don't take you seriously...... ???

Yeah what a dope! That was an Arrow, not a Leader.

Rohan · Dec 30, 2012

Given that the Nortons etc did 6 laps in about the same time as the Ariel did 5 laps, we'd question that 40 mph ?? (they were of course 350cc Nortons)
Good effort though, obviously some serious potential there.
(Scotts aside, was this the beginning of the 2 stroke invasion ?).(in the 250 class)

Unless there was a 250cc Norton in there somewhere ???

Still be interesting to see a 650SS lap time...

worntorn · Dec 30, 2012

acotrel said:
In about 1961 I watched Tom Phillis trounce all of our top guys in the Australian TT at Phillip Island. He would not have been hanging around with the Domiracer at the IOM. But all things considered the twin motor in the featherbed frame can never be as good as the single it was designed for. THe manx engine always sits lower and further forward, and it is a much more developed engine anyway. If you want to see a highly developed twin, have a look at the Paton. The Norton twin motor is surprisingly good for what it is, but it is not in the same league as the Paton or even the Laverda twins. I suggest that a Montjuich 500 would cream the domiracer. The domiracer would have been difficult to develop. I understand that Norton sent one of their guys to buy a Triumph race cam so they could copy it, but they would have found it very difficult to optimise the timings without being able to move the exhaust and inlet cams independently. A better option would have been a Triumph bottom end with a Norton style cylinder head. The Matchless G45 might have been an even better starting point. Some of our guys have fitted XS2 Yamaha roller bearing cranks into those old motors which have the centre bearing.

According th Doug Hele, the engineer who developed the Domiracer, the 500 twin engine with aluminium cases was 28 lbs lighter than the Manx elekton cased engine. Also, because the Manx is such a tall engine, the Dommie racer had a lower centre of gravity.
Here is the quote from Mick Walker's book on dommies-
"Experiments during the past four years have indicated that the Dominator would readily respond to development so that it should not be difficult to extract as much speed as from the Manx (Norton's pukka dohc single cylinder racing motorcycle) , maybe even more. Even with the engine in its present semi-standard form we start with a weight advantage, for it is already 28 lbs. lighter without having to resort to Elektron crankcase castings. Moreover, it is smoother, so we can get away with a much lighter frame. Finally, it has a lower centre of gravity, which should ease handling problems"

Rohan · Dec 30, 2012

It still wasn't as fast as the Manx at the IoM races !! :mrgreen: :mrgreen:

Sad that development wasn't continued though, who knows what may have been....

worntorn · Dec 30, 2012

More to follow....

Glen

daveh · Dec 31, 2012

worntorn said:
According th Doug Hele, the engineer who developed the Domiracer, the 500 twin engine with aluminium cases was 28 lbs lighter than the Manx elekton cased engine. Also, because the Manx is such a tall engine, the Dommie racer had a lower centre of gravity.
Here is the quote from Mick Walker's book on dommies-
"Experiments during the past four years have indicated that the Dominator would readily respond to development so that it should not be difficult to extract as much speed as from the Manx (Norton's pukka dohc single cylinder racing motorcycle) , maybe even more. Even with the engine in its present semi-standard form we start with a weight advantage, for it is already 28 lbs. lighter without having to resort to Elektron crankcase castings. Moreover, it is smoother, so we can get away with a much lighter frame. Finally, it has a lower centre of gravity, which should ease handling problems"

This is new information to me, and I look forward to the next instalment!

Bernhard · Dec 31, 2012

daveh said:
worntorn said:

According th Doug Hele, the engineer who developed the Domiracer, the 500 twin engine with aluminium cases was 28 lbs lighter than the Manx elekton cased engine. Also, because the Manx is such a tall engine, the Dommie racer had a lower centre of gravity.
Here is the quote from Mick Walker's book on dommies-
"Experiments during the past four years have indicated that the Dominator would readily respond to development so that it should not be difficult to extract as much speed as from the Manx (Norton's pukka dohc single cylinder racing motorcycle) , maybe even more. Even with the engine in its present semi-standard form we start with a weight advantage, for it is already 28 lbs. lighter without having to resort to Elektron crankcase castings. Moreover, it is smoother, so we can get away with a much lighter frame. Finally, it has a lower centre of gravity, which should ease handling problems"

Click to expand...

This is new information to me, and I look forward to the next instalment!

Sorry to rain on your parade, this is old information and there is an article on the Domiracer in Roy Bacons Book Of the Norton twins which covers all dominators from the first 500 to the first 750s.
These articles are researched from the earlier MotorCycle archives.

worntorn · Dec 31, 2012

Bernhard, these are old articles and books I'm digging around thru. Since these bikes were a new thing fifty years ago, most of the information available dates back to that time period. Hopefully it is still worth posting?

Glen

The 650SS

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