Found. a true 70 Production Racer

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Dances with Shrapnel said:
It sounds like your context is ancient history; it seems like within a short time, everybody and their brother were enlarging the valves (at least the intake).
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If Nortons only sold a (very small) handfull of these short stroke engines then the ancient history is the only history they have. !
They were well discussed on this forum a while back, and all the shortcomings were listed.

Any subsequent race success is nothing to do with the factory, nor the engines as supplied...
 
lcrken said:
acotrel said:
A short stroke 750 PR would be worth having, however I think the rest is just commercial delusion.
Click to expand...

Except for the fact that Norton never built a short stroke 750 PR. All the PRs (i.e. Commando 750 F.I.M. Production Class Racer) came with standard stroke 750 engines.
Click to expand...


So were the short strokes primarily targeted for the US market for homologating purposes or was the homologation more on an international level?

I have only seen street trimmed short stroke 750's from the factory. Were there any others?
 
swooshdave said:
You guys go off track faster than a drunk on a Saturday night down a country road...
Click to expand...

The suggestion was that this bike has a short stroke engine in it...

If you call that "off track", then just how straight and narrow do you want this forum to be. ?
A single (correct) answer to every post...?

IMHO, its the sidetracks explored that make this forum a valuable resource...
 
Dances with Shrapnel said:
lcrken said:
acotrel said:
A short stroke 750 PR would be worth having, however I think the rest is just commercial delusion.
Click to expand...

Except for the fact that Norton never built a short stroke 750 PR. All the PRs (i.e. Commando 750 F.I.M. Production Class Racer) came with standard stroke 750 engines.
Click to expand...


So were the short strokes primarily targeted for the US market for homologating purposes or was the homologation more on an international level?

I have only seen street trimmed short stroke 750's from the factory. Were there any others?
Click to expand...

So further to my queston above, where does the short stroke fit into the model line up.

I have copied the list provided elsewhere on this forum below:


750cc
Original Commando 4/68-3/69
750 R 3/69-9/69
750S 3/69-6/70
Fastback 3/69-8/70
Fastback II 9/70-12/70
Fastback III 1/71-12/71
Fastback IV 1/72-3/73
Fastback LR (Long Range) 4/71-12/71
Fastback LR MkIV 1/72-2/73
Roadster 3/70-12/70
Roadster II 1/71-12/71
(no MkIII Roadster, apparently!)
Roadster IV 1/72-2/73
Roadster V 3/73-10/73
SS (Street Scrambler) 3/71-10/71
PR (Production Racer) 4/71-10/73
Hi-Rider 5/71-12/71
Hi-Rider IV 1/72-2/73
Hi-Rider V 3/73-10/73
Interstate 1/72-2/73
Interstate V 3/73-10/73
850cc
Roadster 1 4/73-12/73
Roadster 1A 9/73-2/75 (I think that should be 2/74)
Roadster 2/2A 1/74-2/75
Roadster 3 2/75-9/77
Interstate 1 4/73-12/73
Interstate 1A 9/73-2/75 (2/74?)
Interstate 2/2A 1/74-2/75
Interstate 3 2/75-9/77
Hi-Rider 1 4.73-12/73
Hi-Rider 2 1/74-2/75
Hi-Rider 3 3/75-?
John Player Replica 11/73-2/75


Is there a sub category for the Short Stroke Norton or is the above list imcomplete?
 
Dances with Shrapnel said:
So further to my queston above, where does the short stroke fit into the model line up.
Click to expand...

The list covers normal civilian production road models (the Proddy racer was, I think, classed as a road bike). Even though what's supposed to be a short stroke Roadster is shown in the '73 brochure, there doesn't appear to be any evidence that any short stroke production models were actually made.
 
Thanks LAB. I've only seen brochure information on the Short Stroke Norton and as I recall it was dressed out as a street Commando.

Maybe that better explains the poor performance of the Short Stroke that Rohan has alluded to. :)

So is the general concensus that the Short Stroke was never really produced? I recall reading that there are/were factory short stroke crankshafts available and the heads were factory produced. Where did these components end up going to? How did they get to market?
 
Dances with Shrapnel said:
So is the general concensus that the Short Stroke was never really produced? I recall reading that there are/were factory short stroke crankshafts available and the heads were factory produced. Where did these components end up going to? How did they get to market?
Click to expand...

As I think we know, there were a significant number of short stroke engines made, but there doesn't seem to be any evidence that any road-going Commandos were built with short stroke engines intended for sale to the general public-unless anyone knows otherwise.
 
So how and when did these motors go to market?

I get the impression that Norton manufactured way more Short Stroke Engines/Components than that necessary to support a factory racing endeavor. Maybe the sole purpose of the quantities was in support of an attempt at homologation.
 
If the short stroke engine was to have been used by anyone in UK production racing then it would have to have been homologated as an engine in a production machine. Proddie racing was pretty popular in England at that time. The silhouette would also have allowed the less scrupulous to use an 850 engine as unless they were amongst the first finishers, there was little chance of an enforced inspection...and the Tridents were nearly all doing it anyway.

I've heard a number of ex-members of the works teams speak at various times and I clearly remember someone saying that it wasn't popular. On the track it didn't seem to be as easy to keep it on the power as the long stroke engine. Obviously, this reflects the engine as it then was. It produced more power but was slower out of the corners in most situations.
 
The short stroke 750 engines were available as a complete engine from the factory starting in late '73 or early '74. I've seen at least two that were purchased that way. I could have ordered one through Barney Tillman's Sport Center in Los Angeles back in '74, but it was more than I could afford at the time (don't remember what the price was, just that it seemed like a lot to me). I never have seen a parts book with part numbers for the short stroke engines or their unique parts (crankshaft, rods, head, etc.). If anyone has one with prices to post, it would certainly be interesting. The part number for the RH7 head was 064854, but that's the only one I know.

Ken
 
This is really fascinating to me. I am going to show my naivety here as I was thinking there were actually a quantity of (at least) 200 short stroke bikes manufactured and out there because .......drum roll please...........they had a brochure showing them. Ha! This really cracks me up.

A thanks to those who contributed to this thread; it is still a bit of an open chapter. Just because nobody on this forum has chimed in to say they have seen an authentic factory road going short stroke Norton Commando does not mean they did not exist (yeah, I want to believe) but it is beginning to sound like they were never pulled together as a bike but only as an engine. And yes, a short stroke parts book would be interesting to see - from a historical perspective. From what Ken was saying about the years of availability, I suspect the factory effort was quickly loosing steam.

It would be good if we could nail this one down.
 
If they had trouble selling any, it doesn't matter how many brochures they printed. ?

Can recall when they announced the Thruxton Clubman Racer.
http://www.bikeexif.com/norton-thruxton-club-racer
Reportedly, they only sold 'about a dozen'. (?)
This when the Cosworth was coming 'real soon now'.

Anyone got a better pic of one, the fairing was outlined in red ?
 
This is the only other pic I've seen, from Roy Bacon's book.

Found. a true 70 Production Racer

Ken
 
Notice that the ignition was by Lucas Rita. That might be why Ron L thought the PR also had the Rita.

Ken
 
I heard that a most of the 200 or so short stroke engines ended up at the Wasp factory, where they were converted to 850s using a standard crankshaft, standard rods and Omega high compression pistons. By then Commandos entered in production racing were allowed to have 828 cc engines and the sidecar motocross racers went up to 980 cc.
 
Dances with Shrapnel said:
This is really fascinating to me. I am going to show my naivety here as I was thinking there were actually a quantity of (at least) 200 short stroke bikes manufactured and out there because .......drum roll please...........they had a brochure showing them. Ha! This really cracks me up.

A thanks to those who contributed to this thread; it is still a bit of an open chapter. Just because nobody on this forum has chimed in to say they have seen an authentic factory road going short stroke Norton Commando does not mean they did not exist (yeah, I want to believe) but it is beginning to sound like they e.t.c.
It would be good if we could nail this one down.
Click to expand...


I wouldn’t call you naïve Dancers, but I watched a few production short circuit races in the 1970s in the UK where Norton Commando production racers sometimes won.
There was the infamous remark by Peter Williams where Norton kept just 2 bikes specifically for the Brands Hatch Indy circuit that had their whole engine & gearbox mounted 5/8 inch to the left, so these bikes lapped this circuit 2 seconds quicker than anybody else.
You certainly couldn’t buy one of these :!:
 
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