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Did Norton go backwards with the Commando? The 650ss was clocked at MIRA at 119 .Commands struggled to do 112... what would a modern 650 do with proven goodies? How fast where the Dommiracers?
650 v 750
- Thread starter john robert bould
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I believe the 650ss that clocked 119 at Mira had a tailwind. The two way average speed was just under 112 MPH if memory serves.
The Domiracers were very fast as were Dunstall Dominators. Even his very early Model 99 based racer went very well.
From Motorcycle News, November, 1958, letters to the editor:
" Having seen P. Dunstall perform at Brands Hatch on his Norton Twin, which surely must be a Dominator 99, my friends and I would like to know more of the history of this machine which can pass Manx Nortons on the straight. If there is room for an article in MCN it would be much appreciated."
Two weeks later MCN published a two page feature on Dunstall, written by Mick Woollett.
Glen
The Domiracers were very fast as were Dunstall Dominators. Even his very early Model 99 based racer went very well.
From Motorcycle News, November, 1958, letters to the editor:
" Having seen P. Dunstall perform at Brands Hatch on his Norton Twin, which surely must be a Dominator 99, my friends and I would like to know more of the history of this machine which can pass Manx Nortons on the straight. If there is room for an article in MCN it would be much appreciated."
Two weeks later MCN published a two page feature on Dunstall, written by Mick Woollett.
Glen
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john I think your right,take a look at a dommie motors centreline from the crank up through the cylinders and then a commandos,and you,ll see a definite step back
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Is there a fast sports cam available?
Fast Eddie
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Not really sure what you're getting at John... Are you suggesting the Commando would have been better as a 650?
That would be easy to try wouldn't it? My assumption is however, if it were better, people would do it.
Mines an 840cc now its been bored, I often think about making it bigger, I never think about making it smaller!
I think that if all else is equal, and within limitation, a big engine makes a better road bike. Where you are racing and have to stick to capacity limits, its a different story of course.
All only IMHO of course.
That would be easy to try wouldn't it? My assumption is however, if it were better, people would do it.
Mines an 840cc now its been bored, I often think about making it bigger, I never think about making it smaller!
I think that if all else is equal, and within limitation, a big engine makes a better road bike. Where you are racing and have to stick to capacity limits, its a different story of course.
All only IMHO of course.
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Not sure if bigger was better,but in the Seventies BIG sold...when Honda made the statement a GP bike Rep was on the cards ,people waited with baited breath...then out popped the NS400..a full 100cc less than expected///yam RD500 sold well. Suzuki RG 500 sold well, but a 400 honda? What did buyers do? yep bored it out to 500! I would guess if a 120 mph 650 Commando was produced..it would have flopped, simply because the market wanted Big cc bikes,,,sorry Ed size as always been a man thing . Bore your Commando to 1000cc and it still will lag behind my 500..ever sat on a RZV500 at 12000 rpm? mines tame, Stan Stevens 700cc 140 bhp now thats quick!
Fast Eddie said:
Matchless
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I have a 650,750,& 920 & they are all great to ride in their own right. The 650ss steers the best, no question. It also has a willing & sweet motor, but lacks the torque of the bigger engines. My favourite is the 920. I never stop grinning when I'm on it.
Maybe the ultimate Commando would be a slightly bigger featherbed frame, with a 900cc engine with Jims rods & pistons. I say bigger frame as I find the featherbed bikes somewhat on the small side.
Maybe the ultimate Commando would be a slightly bigger featherbed frame, with a 900cc engine with Jims rods & pistons. I say bigger frame as I find the featherbed bikes somewhat on the small side.
Fast Eddie
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john robert bould said:
I think you're backing me up John... Stans 700 is faster than your 500...!?
Remember I did say 'all else being equal' ie same engine in 650 format Vs 850... and I'm talking about road bikes.
But anyway I didn't say bigger is faster, I said bigger makes a better road bike, ie bigger has more torque, probably only the same power, but at a lower and broader rev range. So you can have more real world road speed, at lower levels of engine stress. Basically this is what Norton did when they went from 750 to 850.
And NO! There's no way I'd put my 850 pushrod 4 stroke antique against your 500. I was actually looking at one on eBay recently and was momentarily tempted. I'm not bad around Mallory on a good day John... So in a moment of high jinks, I might just try and keep up with you around there. Probably have to rebuild it afterwards though...!
I have a 650ss that is in good tune, fresh engine. Once it hits 4 k, it does pull rather well.
But for real roads the 850 Commando MK3 has it licked. For example, pulling up Dyno hill in top, both bikes similar overall gearing, the 650 pulls down to 63 MPH in fourth at top when hitting bottom of hill at 70 MPH.
The 850 Commando pulls over the top in fourth at 75 MPH when hitting the bottom at 70 MPH . The difference in riding a bike that eats up a hill and accelerates as it climbs vs one that slowly loses ground until a downshift is needed, is profound!
I can only guess that a 750 would be about in the middle, that is it would hold a steady seventy MPH up and over.
And then there is the vibration. The Commando was a good development.
Glen
But for real roads the 850 Commando MK3 has it licked. For example, pulling up Dyno hill in top, both bikes similar overall gearing, the 650 pulls down to 63 MPH in fourth at top when hitting bottom of hill at 70 MPH.
The 850 Commando pulls over the top in fourth at 75 MPH when hitting the bottom at 70 MPH . The difference in riding a bike that eats up a hill and accelerates as it climbs vs one that slowly loses ground until a downshift is needed, is profound!
I can only guess that a 750 would be about in the middle, that is it would hold a steady seventy MPH up and over.
And then there is the vibration. The Commando was a good development.
Glen
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Poor manufacturing and design on a lot of things also affect the 750/850 a LOT, so keep that in mind. Having opened up both, I would reckon that the 500/650 is probably a little more...thought out in some regards. By the time the 750/850 rolled out there were a lot of little quirks that were somewhat swept under the rug and ignored that could have had simple solutions if any bothered. Things that spring to mind: oiling ports on the head/alignment, valve/rocker geometry (holy heck is that awful), cam oiling, oil pump rate, oil pump type/lash/sealing, cam hardening, casting porosity, isolastic arrangement/design, etc.... Many quirks were sorted out by the time the 850 came out but the market had definitely changed a lot, as had Norton's priorities.
Given a few more years (but with enough money to actually rub two shillings together) I'm sure the 750/850 motor would have had the opportunity to be developed quite a bit, but it's also a question of IF anyone would have actually bothered if they were selling.
Given a few more years (but with enough money to actually rub two shillings together) I'm sure the 750/850 motor would have had the opportunity to be developed quite a bit, but it's also a question of IF anyone would have actually bothered if they were selling.
Norton was developing their parallel twin and their entire bike constantly until 1975. They really threw everything they had at the design of the MK3. Stronger cases, stonger crank, sealed swing arm, disc rear brake, and vernier isolastics are just a few of the improvements.Somewhere I read that there were about 150 changes from the previous model. Pretty much all of the the changes were intended as improvements and most added some cost.
The early Dominators including the first 650ss had a low output 3 start oil pump which Norton changed to a six/start in the mid sixties. The Dynamo was replaced by a small alternator, then the small alternator was replaced by a larger one and so on. So the Dominators were being improved upon as well, but the rate of change seems to have really accelerated with Commando production.
I know of two 850s that have covered over 100,000 miles without touching the bottom end. One has had the top end freshened once, the other not at all. It still runs, tho it is very tired! I think Norton had a very good machine in the Commando.
The early Dominators including the first 650ss had a low output 3 start oil pump which Norton changed to a six/start in the mid sixties. The Dynamo was replaced by a small alternator, then the small alternator was replaced by a larger one and so on. So the Dominators were being improved upon as well, but the rate of change seems to have really accelerated with Commando production.
I know of two 850s that have covered over 100,000 miles without touching the bottom end. One has had the top end freshened once, the other not at all. It still runs, tho it is very tired! I think Norton had a very good machine in the Commando.
A
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Ta.
Are you referring to the Cosworth Norton ?
Since Cosworth were doing the design, quite possible they looked in their own cupboards for DFV stuff/inspiration. !
Bit after Franks time, this was quite late in the Norton saga.
Been discussed here before.
Car designs don't always good motorcycle engines make, and this was no exception.
Initially anyway.
The later Quantel versions were mentioned here, and sorted they went quite well.
Since Cosworth were doing the design, quite possible they looked in their own cupboards for DFV stuff/inspiration. !
Bit after Franks time, this was quite late in the Norton saga.
Been discussed here before.
Car designs don't always good motorcycle engines make, and this was no exception.
Initially anyway.
The later Quantel versions were mentioned here, and sorted they went quite well.
A
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Ta.
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john robert bould said:
Maybe the 600 has a bearing on things.
There was a time when a 650cc motorcycle was regarded as large capacity let alone alone a 750, with sales of over 50000 units it was hardly (The Commando) a backward step, it should have been the savior and it was for a while.
Plenty of British motorcycles stretched original concepts, stroke them, increase the bore until you needed new engine cases.
Time Warp said:
There was a good historical reason why plenty of british engines were stroked in particular, not just bike engines.
The British Tax system taxed cars on their horsepower rating, and as this was derived from steam engine days,
only the bore size was considered in the formula to calc horsepower.
This meant engine makers could increase the engine capacity by stroking, AND STILL PAY THE SAME TAX.
Using the same machinery to produce newer engine designs also saw similar strange things.
Keeping the same bore, or stroke, meant the same boring bar or crank grinding machine would suffice for the new designs.
Makes sense, if the budget for new designs was on a shoe string ??
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Subject: 650 v 750
folks were indeed interested in power and went that direction in droves, they also had other ideas as far as what is important and encompasses a touring bike,
picture a norton alongside a goldwing
frankdamp said:
folks were indeed interested in power and went that direction in droves, they also had other ideas as far as what is important and encompasses a touring bike,
picture a norton alongside a goldwing
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