Combat 2S with small standard head

Anyone ever try this combo besides me?

Re: Comat 2S with small standard head

That's basically just a standard 750 with a 2S cam. Must be plenty of folks who have tried it. 2S used to be a popular choice for a street bike upgrade.

Ken

Yep just a standard prior small port 750 head on Combat engine with 2S cam,so would of thought others tired it but so far I only know 2 and both were very pleased, me and DynoDave who won a rally dyno test a couple to 3 hp above everyone else's hopped up spiffed up disappointments. IRRC DynoDave got 49.8 hp.

Read On : http://classicbike.biz/Norton/Mags/1960s/1969Norton.pdf

I always thought that article was interesting because it shows a real production racer that is not yellow, and does not have a disk front brake. Must be the rarest of the type.

Very interesting article especially the handling part and power potential prior to the over ported bent path CHO Combat head. I'll tell you what an 130+ mph 350 lb standard head Commando that can handle sure upsets the world beliefs of them balloon tire wonders in the real world and mine too were shot to smitherines. Yet the '68 P!! would pass 130 before 1/4 mile to pull about 20 mph more given a bit more t/d. I never ever held on long enough to find out what top out was like on that thing, for one thing the vibration became injurious. Race bikes have no speedo's for some reason so only way i knew the speeds was by what other said their showed when I pulled past. The only ones that could or did were the 1%'rs on big Twin Harleys and pissed me off I could not run away from them over the ton just neck and neck racing till we ran out of opens with my main advantage at those speed being a smaller frontal area and able to tuck down lower tighter.

beng said:

I always thought that article was interesting because it shows a real production racer that is not yellow, and does not have a disk front brake. Must be the rarest of the type.

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It is an interesting early PR article. I've always assumed it was a prototype, not one of the production bikes offered for sale. Besides the drum brake, the footrests and controls are pretty much modified stock bits, not the pieces that were standard for the PRs. They look a bit like the bikes built up for Paul Smart and others to race prior to the official addition of the PR to the Commando product line. The exhaust pipes are quite different from the ones on supplied on the later PRs and in the Norvil racer catalogs. They have a unique curve at the engine to pull the pipes over next to the downtubes, but those might have been the same as fitted to the first PRs, the ones with the old Atlas style silencers.

Norton didn't offer the PR as a production bike until the 1971 model lineup, so a test bike in 1969 would seem likely to be a pre-production prototype. To further confuse us, the race shop at Andover built production race bikes for the factory team that differed from the ones supplied to dealers, as well as production race bikes to order for customers.

I think there is sometimes confusion in the use of the term production racer. The factory adopted "Production Racer" as a model name for the bikes sold through dealers as Commando Production Racers, but the term is also used as a generic label for any Commando that fits the FIM definition of a production racer from the 1968 and later rules. So there are a fair number of Commando production racers that were built up by racers from standard Commandos using FIM approved parts from the factory "Norvil" catalog. The Commando production racers ridden by Paul Smart, Peter Williams, and otheres in the 1969 and 1970 period were not quite the same bike you could order up from your local dealer in 1971.

Butcher/White Factory PR ca. 1973



Dave Croxfords Factory PR ca. 1973



If you'd like to see a PR in non-yellow livery, here's mine, with a color scheme I tried briefly, back in the early '70s, before going back to yellow. It was still pretty close to original, with just an oil cooler and a Sebring ignition added.



Ken
Ken

I always wonder why race classes are often restricted to limit development ? Surely potential customers are not fooled that production racers resemble the bikes you can buy at your local dealers ?
If the class was not solely for production racers, it could have been regulated to only include 750cc two valve four stroke singles, twins and triples. And the limitations on development could have been largely removed. The winners would still have promoted their brands. We might have ended up with a very appealing competition ? In that sort of class, it would take a really good bike to beat a hot commando, and the costs of competing would not have been that much greater. To my mind, imposing rules is sometimes like beating yourself over the head with a baseball bat.
Realistically how much behind our current fast 750cc commandos were the Norton production racers of the 70s ? Just looking at those photos, I know I would have to work pretty hard to beat a good guy on any one of them with my Seeley. ( One day,before I die.... I really wish ! ! )

Back in the 80s we used to run the Castrol 6 Hour Production race in New South Wales. It was strictly regulated and rigidly scrutineered. At that time a friend of mine was a Suzuki Importer. A container load of bikes would come from Japan, and my friend would have a letter which specifed the engine numbers of bikes in that container to be used in the Castrol 6 Hour Race. They always passed scrutineering.

hobot said:

Yep just a standard prior small port 750 head on Combat engine with 2S cam,so would of thought others tired it but so far I only know 2 and both were very pleased, me and DynoDave who won a rally dyno test a couple to 3 hp above everyone else's hopped up spiffed up disappointments. IRRC DynoDave got 49.8 hp.

Click to expand...

At the 92 rally, there were hot rods that went to about 56 hp. But mine was the highest declared stock commando. Leo Geof told me the best professionally tuned combat he had ever witnessed was 49 rwhp. So he was impressed with my combat's 47 rwhp.
Most stock commando's showed 38 to about 43... more 850's were at the higher end.

dynodave said:

At the 92 rally, there were hot rods that went to about 56 hp. But mine was the highest declared stock commando. Leo Geof told me the best professionally tuned combat he had ever witnessed was 49 rwhp. So he was impressed with my combat's 47 rwhp.
Most stock commando's showed 38 to about 43... more 850's were at the higher end.

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It's refreshing when someone comes on here with a voice of reason about rwhp numbers for these bikes.

The feature I was asking about was if others ever experienced how pleasing a standard small port head was on Combat engine -IRRC that was something that David had on his 'stock' engine in a combo never factory issued. If Peel's weird combo only put out 50 rwhp I'd likely never been heard of again after 2003 in any Norton circles. Much as I like the quaint performance of a good Combat its constantly depressing compared to what keeps me interested. Trixie is stop gap to sell off someday as essentially unmolested example getting rarer and rarer. I've thought about putting past Peel engine in her but likely kill me d/t the horrific power handling. Got the Drouin which which is simple bolt on device that'd bump power up over most Cdo's but I know I couldn't enjoy it much before drive train tore up or bike threw me off Hinging. Kenny I am the Only one I read of making Any claims of embarrassing sports bikes by pure acceleration power with factory parts engine up to the ton and reaching over 130 to keep up in opens, so take your challenge personally in good sportsmen way to put it back and see who eats crow in public. I don't want to spend what it takes to make another Commando handle learned power, so thinking of putting it in a boat or a chopper. But if what I claim can be reproduced it might influence furture builders towards unexpected road joys and strangers reactions. Hehe when I got '00 SuVee in '01 d/t no-name clapped out Combat down time I'd run it a bit over 120 to its gradual top speed in opens that allowed it, thinking how pitiful Commando's are > but later on Peel I found 120 to be easy to reach any where and good cruise speed with good pull still on tap and no need to tuck down till aiming for over 130.

Holmeslice said:

dynodave said:

At the 92 rally, there were hot rods that went to about 56 hp. But mine was the highest declared stock commando. Leo Geof told me the best professionally tuned combat he had ever witnessed was 49 rwhp. So he was impressed with my combat's 47 rwhp.
Most stock commando's showed 38 to about 43... more 850's were at the higher end.

Click to expand...

It's refreshing when someone comes on here with a voice of reason about rwhp numbers for these bikes.

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+1. That's a mild way of putting it, Kenny. My AHRMA Sportsman 750 race bike made 62 or 63 rwhp on the AMI dyno at Daytona one year, and you'd be amazed at the number of people who thought that was low! That bike won a lot of AHRMA races, including at horsepower tracks like Willow Springs. I think the standard for a 750 Commando race bike is probably higher now, with all the upgraded parts available, but not as much as some folks seem to think.

Ken

I was hoping Dyno would of gone into what he thought helped his engine by mentioning the upsetting head he'd fitted.

Well Hobot, I ran a '71 Fastback as a 'production class' race bike in '75

It ran the small ports, 30mm carbs and a standard cam (not 2S!) and was only limited on top end by standard valve springs going into valave bounce at 7,200 on standard gearing. It was never at a real disadvantage to 'production racers' that had high compression (long kickstart lever was a bit of a giveaway there), 4S cams and 33mm carbs....

The worst aspect was the drum brake fading away after 5 laps of a 6 lap race, but it gave me bunch of top six placings as a novice racer.... and it was sweet enough to ride...

SteveA » Wed May 22, 2013 12:43 pm
Well Hobot, I ran a '71 Fastback as a 'production class' race bike in '75

It ran the small ports, 30mm carbs and a standard cam (not 2S!) and was only limited on top end by standard valve springs going into valave bounce at 7,200 on standard gearing. It was never at a real disadvantage to 'production racers' that had high compression (long kickstart lever was a bit of a giveaway there), 4S cams and 33mm carbs....

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Alrighty SteveA, that is the reality check I was hoping for to help me rationalize my choices on next Peel and if recreating her first Combat "Bombardier" power surpriser. Also a reality check on factory valve limits that almost got me passing a semi with nasty sounds and mifires some where in begining of red zone. It should also be encouragement to other wanting some big road grins w/o spending an arm and first child on it. With cam degree otimalized and bigger carbs would be even better than expected. When Peel was in her prime I mostly only used 2nd and 4th from launch to top out. I think Peel was under carb'd so would try that if redoing it again. I've had two Cdo big engine spenders in the past tell me they did all their drag contests just dumping WOT in 4th and handing on and always got there first. Silly kids stuff we should be ashamed of now.

hobot said:

I was hoping Dyno would of gone into what he thought helped his engine by mentioning the upsetting head he'd fitted.

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The suspected aspect of good performance on the stock 1970 head used on my combat, was the "short port" i.e. the shape of the bowl behind the guide and turn down to the seat. Maybe a bit of relief to the side of the guide helped too. Othewise, it was a stock 28.5mm port head. I hope to mimic this shape in one of my atlas heads for my "hot rod" featherbed, also it will run my modified 2S grind on a 20M early type core.

A post form a long time online friend in NY Joe Piska who recently found Commando joy after 3+ yrs project. '71 small port head on Combat bottom + rump rod. ---- hobot ---------


On 5/27/2013 8:12 AM, jcb500@aol.com wrote:

On 5/25/13, I got it running, lots of $, lots of anguish, much time and studding involved. If I had only listened to Jim Noll of British Bike Connection, I would have spent a less loot for sure. Jim's exact words were, " Put
the basket case together, get what you need to make it run and safely drivable. Then go from there with the upgrades. You may not even like the way it runs or rides, if not, then dump it off." I always wanted a drum brake
Commando, so I just had to fool w/ the soup, after all I'm the Chef

Here's the best part. After the initial heat cycles and engine run in's. I took it out on the Pavement. Now mind you, I had not driven a Commando before, have drivena 750 Triumph, a 650 BSA, even a Yam TX 750 for a while, but
never a C'do. I was still in engine break in mind set, so was just rolling it up and down in second gear on the roads. On CR 115 there is this area of un easy road were the pavement is a bit rippled, just as I got the front wheel to the
area, I was tooling along at about 2,ooo RPM's and I opened the throttle as far as I could. The front end lifted a bit, just about 4 inches, and carried the bike about 20 yards! I had no idea a 750 cc Vertical twin would do such. I am
pleased, so when I got back the shed I had to call one of my Norton Mentors, Doc. Shiver and share my joyous excitement.


On 6/1/2013 7:52 AM, jcb500@aol.com wrote:
> I had no idea that this Commando would be so fast!
> I ran her out this AM, flipping 75 mph in 2nd gear w/ room
> on the tach! 12.8 sec. standing 1/4 mile? Yea easy!!
>
> It pulls right up there like my 1100F/C 4 cylinder. Much
> more intoxicating than an Iron Head Sportster, or a big
> twin Shovel Head, and it handles, I am so pleased with
> my not-so-new toy!
>
> I'm glad I spent the loot, it was really worth it! I now
> understand the romance of a Commando!
>
> The right foot shift and left foot brake will take time to adjust to!
>
> Joe

lcrken said:

Norton didn't offer the PR as a production bike until the 1971 model lineup, so a test bike in 1969 would sem likely to be a pre-production prototype. To further confuse us, the race shop at Andover built production race bikes for the factory team that differed from the ones supplied to dealers, as well as production race bikes to order for customers.

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Norman White had this to say about the Cycle World Production Racer:

" Yes I do indeed know of the production racer tested at Orange County. This machine is one of 3 built at Woolwich in 1969 by Wally Wyatt and John Mclaren,who still works along side me here at Thruxton. Enc. is a picture of the three on the Woolwich factory roof,soon after construction. We soon discarded the drum brake for the NVPS hydraulic disc. Hope this is of interest to you. Regards,Norman. "

Looks good . Thanks for posting . Any guesses on if a hacksaws meet the footrest plates . ?

What does it have in common with a GT6 , Vitesse , Triumph Herald ( Thats a CAR to those wondering ) .



If someones got both , or wants to check . Theres updates to full floating for raceing Triumphs too . ( Triumph CARS )
These go for snaff all new . The Std. Triumph ones .