Many great engineers had a similar motto, “Simplify [or Simplicate] and add lightness.” For motorcycles there could also be a corollary, “and lower the centre of gravity.” For the first two-thirds of the twentieth century several fine motorcycle companies adhered to this rule.

Many have wondered how Norton could possibly adopt a pushrod engine in 1948 when they had already been making good OHC engines for a couple of decades. [OHC probably predates OHV but this is not completely clear. The Buick patent is for a valve-in-head design but it applied to both OHC and OHV. Whichever type came first both schemes can move valves reliably.]

Norton might have been able to build some sort of Manx Twin but it would have been very expensive to make. Cost is very important for a street bike which needs to be priced similar to competing designs. Bert Hopwood’s compact pushrod “hemi” was simple, light, and affordable, with the weight down low. It was a fine choice for one of the greatest road bikes ever made and deserves to be remembered that way.

De Dion Bouton, in the 1890s, had ohv (in a hemispherical head) demonstrably years and possibly a full decade before anyone had ohc. For a British maker, Matchless had an OHV race bike in 1904. And ohv v-twins for 1905 or 1906 ?.

In 1948, Norton had had OHV singles for 26 years, and OHC for only 21 years, these were both "hemi" before it was known as such, what you on about ?
Or are we only talking twin cylinder ohv Model 7 Norton Dominators ?

P.S. As the owner of an early Model 7 Dommie twin, as I like to quote "440 lbs dry, and half the horsepower of a Commando".....

Sounds like you need to Drop a Commando engine in it , Or a Triumph . Or give it a Tune , Possibly .


These O.H.V.s are Just a passing phase . The Side Valve Will Return .

Matt Spencer wrote:Sounds like you need to Drop a Commando engine in it ,:

This is a joke, right ?
Those plunger sprung rear suspension units can get in a knot with barely 30 hp !.
If you look closely, factory plunger framed race bikes at some of the rougher tracks had little hydraulic damper units fitted. Without them, the rear suspension is little more than a glorified pair of pogo sticks. And only the axle to keep them synchronised....

And in case you haven't met these brazed plunger frames, they are a trifle prone to cracking in various inconvenient places with rough treatment. More hp would not assist here. But being brazed meant any village blacksmith could repair them.....

Matt Spencer wrote: The Side Valve Will Return .

Plenty of lawnmowers are still sidebangers.
So in some sense have never gone away.....

Rohan wrote:...what you on about ?

What I am on about is the constant noise from trolls on this site about what is wrong with Mr. Hopwood's engine. The idea being that it is an obsolete design from 1948 compared to Honda's invention of the OHC engine in 1969.

DeDion made an OHV in 1890 and the Marr runabout had OHC in 1903. This means both types go back more than a century and an OHC engine is not somehow way more modern than an OHV type.

Of course, one new type from the middle of the twentieth, the Wankel, is no longer in production now that Mazda has stopped making them so it looks like it's going to be pistons and poppet valves for the forseeable future.

What this site needs is more on what is right with the Dominator/Atlas/Commando engines and less comments from the trolls about how imperfect it is. Trolls, left unchecked, can eventually destroy a website.

But this stuff can go on forever, Suzuki "invented" the water-cooled two-stroke in the 1970's (just don't tell Scott). Heck that unnamed farm-implement manufacturer from Milwaukee "invented" Isolastics in the 1990's!

Vince

Unclviny wrote:But this stuff can go on forever...

Vince

Yes but the continual Norton bashing should not be happening on accessnorton.com to the extent that it does. Since I bought my '74 Commando new in '75 I have never regretted the decision and parts have always been easy to find. It does not bother me that the little "Hemi" is a pushrod engine since most of the best engines I've owned had pushrods. My '62 Parisienne was nothing exciting but I really miss my '69 Wildcat with the 430. That one had pushrods and 500 pound-feet of torque. You could feel the earth shift on its axis when you opened the secondaries on that one. [Perhaps I exaggerate but it sure felt like the Earth moved.]

P.S. I generally try to buy products made in North America. Just recently I bought some made in U.S.A. North Star runners. My brother-in-law always thought I was crazy for buying domestic but now that his retirement fund is in jeopardy he tells me I have been right for the past thirty years. That and $2 will get me a ham sandwich, I guess.

If this whole discussion is going to degenerate into the politics of globalisation, then you are just as much a troll as some of the other comments on this site..... ?

P.S. In case anyone didn't notice, we are all in the middle of a giant economics experiment.
"Don't blame me, I didn't vote for it".

Murray B wrote:

Rohan wrote:...what you on about ?

What I am on about is the constant noise from trolls on this site about what is wrong with Mr. Hopwood's engine. The idea being that it is an obsolete design from 1948 compared to Honda's invention of the OHC engine in 1969.

DeDion made an OHV in 1890 and the Marr runabout had OHC in 1903. This means both types go back more than a century and an OHC engine is not somehow way more modern than an OHV type.

Of course, one new type from the middle of the twentieth, the Wankel, is no longer in production now that Mazda has stopped making them so it looks like it's going to be pistons and poppet valves for the forseeable future.

What this site needs is more on what is right with the Dominator/Atlas/Commando engines and less comments from the trolls about how imperfect it is. Trolls, left unchecked, can eventually destroy a website.

In 1948 the compact, light, parallel OHV Norton twin, of pre-unit construction, was comparable to the earlier Triumph design. Fast forward to 1969 though and it was not comparable to motors from the Japanese, which didnt vibrate, leak oil, or fall apart when ridden hard. This massive technology gap effectively spelt the end of the British motorcycle industry, as buyers simply seemed to prefer Japanese machines!

Facts are sometimes pretty hard for people to grasp, and like it or not pitting a bike fitted with a 1948 designed motor, and a hastily thought up anti vibration frame, against the new Japanese superbikes, was never going to work commercially.

Had the British motorcycle industry not been compromised by greed and mismanagement for decades though, the story may well have been quite different, and there could well have still been a strong motorcycle industry in the UK, rather than an assembly plant putting together parts from Thailand, and a crook ripping off customers money!

Dear Murray, You are in danger of preaching to the choir here. It's a Norton site and we like them a lot, not because they are perfect but actually because they are not, we like the character, the foibles and the fun and challenges that we have all had and continue to have with our bikes - in my case fixing them up gives me more pleasure than riding them, although I thoroughly enjoy this as well. You have posted exactly 16 posts to date and each one has been full of piss and vinegar about how the Japanese stole everything good in the world and cheated the rest of us out of some sacred legacy. There may actually be some Japanese Norton enthusiasts on this site, there are evidently others including myself, who take a contrary view to yourself in these highly charged discussions.

Many posters on this site have made hundreds of useful and positive contributions to our general knowledge on things pertaining to Norton and you yourself are clearly a fellow who has a lot of experience with a Commando, having owned one from new. Why not post some photos of your bike and a few observations about how you have managed to keep it in service during your lengthy ownership? I am convinced that you will receive a positive response.

Dave M

Carbonfibre wrote:In 1948 the compact, light, parallel OHV Norton twin, of pre-unit construction, was comparable to the earlier Triumph design. Fast forward to 1969 though and it was not comparable to motors from the Japanese, which didnt vibrate, leak oil, or fall apart when ridden hard. This massive technology gap effectively spelt the end of the British motorcycle industry, as buyers simply seemed to prefer Japanese machines!

Facts are sometimes pretty hard for people to grasp, and like it or not pitting a bike fitted with a 1948 designed motor, and a hastily thought up anti vibration frame, against the new Japanese superbikes, was never going to work commercially.

Had the British motorcycle industry not been compromised by greed and mismanagement for decades though, the story may well have been quite different, and there could well have still been a strong motorcycle industry in the UK, rather than an assembly plant putting together parts from Thailand, and a crook ripping off customers money!

Since you always seem to discuss with the benefit of 20/20 hindsight, there is not much to say.

Except that to call Nortons 1949 Dommie Model 7 "light" is putting the cart before the house - its heavy ! It was one of the heaviest 500cc twins of the time in fact - even more than similar 650 models from other makers. That iron cylinder head weighs a ton. And the frame is heavy, and even the tank and mudguards are considerably heavier than their single cylinder cousins parts.

Also, you keep rabbiting about about ancient designs - but harley, guzzi, BM and a few others survived with pushrod motors, and some still do. So thats not a prerequisite fo " modern" design. ? If all the small componentry and detail is updated, an old design can still be modern ?
A good Commando is still quite a capable bike in modern traffic, so its "design" is not the problem.

A lot of folks would suggest that a large part of the oriental motorcycles success story was simply attention to detail - fuel taps that didn't leak, handlebar switches that kept on switching, clutches that stayed put and were self cleaning, wide enough casting joints that didn't leak oil, sealed wheel bearings, oil pump systems that always kept oil pumping, etc etc. Something that didn't need constant repair and attention. The japanese showed it was possible......

Sure very old fashioned bike design bikes continued to be made long after the British motorcycle industry was finished! However had BMW, Moto Guzzi, Harley, and no doubt a few others, been managed by the clowns running the British industry, then I doubt very much any of them would have still been around today.

You keep shifting your point of discussion ?
So now its not old design, its management ?
20/20 hindsight is a wonderful thing....

But may we remind you that Nortons were profitable with the Commando to the end, it was the political shenanigans that brought them unstuck. Perhaps your next rant will be politicians ??

And then you see an Enfield engine fitted into a modern chassis, and realise that anything can be modernised. Although with EFI and leccy start and leccy ignition and 5 speed, the Enfield is already 'modernised' in the engine dept. ??

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