Combat engine or not

they wernt all dogs : http://www.studebakergarage.com/1972_no ... mmando.htm

START at ' NOT ' Thrird Paragraph . page 56 . http://www.classicbike.biz/Norton/Mags/ ... andoCW.pdf of the best laid plans of mice and men .

one artical mentions the Optional Disc Brake & optional Combat Engine , in 1971 ? . American Magazine .

When I bought my roadster (at Comerfords for export to USA) in June '72 I wanted the disk brake but with a standard engine. It was not available separately. If I wanted a '72 model with the disk brake I had to get the combat engine.

But now I'm really glad I did!

Russ

To summarize on hobot's annoying restating the archival list of Combat characteristics its "entirely possible" L.A.B. is correct on the possibility of a non Combat standard power plant/bike being sold that shares even one of the Combats infamous new features but its *Highly Unlikely* any did so. After a decade pestering INOA, NOC, Brit. Iron and world wide vendors and builders I have yet to come across someone that had to go outside a factory serial numbered Combat parts book numbers to restore to original issue. Oil filter, turn signals, steel tanks and drum brake did not come on real Combats of the era, unless of course someone paid extra to bribe a vender or convert themselves, which don't count as factory issue. We need to hear from a single someone that bought a Combat w/o all Combat items to lend weight to L.A.B.'s otherwise accurate dependable reports.

hobot said:

its "entirely possible" L.A.B. is correct on the possibility of a non Combat standard power plant/bike being sold that shares even one of the Combats infamous new features but its *Highly Unlikely* any did so.

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That's not what I said. I believe you need to re-read what I did say.

hobot said:

After a decade pestering INOA, NOC, Brit. Iron and world wide vendors and builders I have yet to come across someone that had to go outside a factory serial numbered Combat parts book numbers to restore to original issue. Oil filter, turn signals, steel tanks and drum brake did not come on real Combats of the era,

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Combats not having turn signals is definitely incorrect. The first Combats were Interstates, and as far as I know, all, or at least most Interstates had turn signals as standard.
http://www.classicbike.biz/Norton/Mags/ ... Mag-CG.pdf

1972 "Combat" Interstate 750, probably "EXP 01

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1972 Roadster Combat "Handgrenade" model (pin pulled at the factory)

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As for the spin on oil filter, it was introduced at serial 208754, so well within the range of Combat serial numbers.

hobot said:

We need to hear from a single someone that bought a Combat w/o all Combat items to lend weight to L.A.B.'s otherwise accurate dependable reports.

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Again, unfortunately you've either misread or misunderstood what I said.

Ok L.A.B. I'm more pleased by your corrective attention than upset to be set straighter by your intense awareness to Commando details. My March pre-Peel was an all fiberglass Interstate with dam turn signals [at extra cost] but my Trixie came as September plain Jane Steel Roadster Combat though did have oil filter added. I used to buy extra signals by the bag full till I both realized how useless and hard to keep working so gave em all loose ones away and recently found Peel old rear fender with signals still on and another spare front signal I don't know what to do with. Still its so rare to hear of a drum front Combat spec engined Commando I can't give single example so await more years in case one is ever revealed to us. I've a pretty good list of past Norton vendors calling me easy money, Ron Fratenelli is one of em so will ask them if they ever came across a mixed up standard '71, '72 or '73 from factory. I will eat crow in public reporting here if I do find one exceptional '72 Standard.

I was unsure if my pre-Peel had 2S cam till DynoDave gave me a number chart degree list instead of blurry graphics to measure on rockers to see yep 2S cam along with all the expected advertised Combat only features. Compression testing is another way to collect clues w/o full tear down exam but too many reasons for lessor pressures its only a clue. Quickest way is hold on past 6800 into red zone. My SuVee 70hp/365 lb is very eager to run up to 90 mph while peddling up extra gears then losses pull to 115+ish while my pure Trixie 19T Combat can easy match it up to 90 but then gets its second wind and pulls rather harder to higher top speeds if I let it but only have a few times to make sure.

L.A.B. can you tell us which 750's allowed Norton pistons to stick up proud of cylinder surface by .050"? All of em or only Combats?

so here is one that bought a NEW 72 combat. it had oil filter, steel tank and disc brake but NO turn signals.

hobot said:

Oil filter, turn signals, steel tanks and drum brake did not come on real Combats of the era, unless of course someone paid extra to bribe a vender or convert themselves, which don't count as factory issue. We need to hear from a single someone that bought a Combat w/o all Combat items to lend weight to L.A.B.'s otherwise accurate dependable reports.

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Mine had the turnsignals also but I took them off after the first tipover in the driveway when they destroyed my headlight brackets. They were optional in 1972. I don't think they were a legal requirement in the US until 1973.

Anything external to engine to determine if its a Combat or not is a non determining factor whether its power plant's the real deal or not. I'd put down a money bet [small amount] that any black barrel rear breather RH disc brake Cdo within the serial numbers L.A.B. posted has a Combat Bomb milled head 2S cam engine in it from factory, not a standard spec. My 2 examples only reveal how they came to me with external variation not how Norton and dealers sold them new.

1972 Fastback, Silver barrels, disc brake.

If it Blows Up at 8.000 rpm , its a Combat .

If it Blows Up at 8.000 rpm , its a Combat .

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I would think any Commando taken to 8K would self destruct

Norton said that the maximum "cruising" rpm of a 850 is 5800, with the redline slightly higher

it wasn't the cam or the compression that made Combats blow up, it was the main bearings in as little as 5000 miles, Norton had a nightmare on their hands with warranty claims

perhaps the best 750 was the 1973, having the beefed up pieces as the 828 introduced that year

Nice example L.A.B. but paint is external to engine parts inside so not a real clue, just cosmetic. Btw the factory issue Combats will float their valves somewhere in mid red zone I found out after 6800-ish when surprise 3rd piston 2S mixture packing power kicks in though over size ports. Brochures and ads - anything goes so we still await someone reporting receiving a non Combat '72 to fool us. Maybe the current poster will eventually find out for us if I'm wrong again as usual. There was a time when un-leaded octane changed at pumps so a number of detuned Combats attempted by just going to standard cam that word soon got out this aggravated detonation even more.

1up3down said:

If it Blows Up at 8.000 rpm , its a Combat .

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I would think any Commando taken to 8K would self destruct

Norton said that the maximum "cruising" rpm of a 850 is 5800, with the redline slightly higher

it wasn't the cam or the compression that made Combats blow up, it was the main bearings in as little as 5000 miles, Norton had a nightmare on their hands with warranty claims

perhaps the best 750 was the 1973, having the beefed up pieces as the 828 introduced that year

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My general description of the combat failing is first and foremost the crankshaft. The main bearing failure is a resulting symptom of the cranks flexing due to flywheel over loading the strength of the crank. Eventually the cranks breaks. Main bearing failure is remedied by "superblends" but crank breakage is not fixed by superblends....
However it is the cam and compression and porting/carbs that allows the engine to rev until destruction.

I have seen in our club, an original 72 hi-rider, drum brake, fiberglass tank, 30mm carbs, combat breather cases, but not combat state of tune.
Also approximately in 1980 I worked on my friends 72...200205* definitely a combat... and it was an interstate, disc brake.
It was very low miles but we put in superblends anyway and it had not been taken apart previously. So I don't really believe the service releases 100%.

*Edited by the moderator as dynodave subsequently discovered the number to be 202005.

hobot said:

Nice example L.A.B. but paint is external to engine parts inside so not a real clue, just cosmetic.

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So what are you saying now? That not all Combats had black barrels? :shock: :wink:

NEW springs ( as in a NEW motorcycle ) with a 18 yr old , that doesnt LOOK at the Tacho , running it ' flat ' in the gears . . . .



VICIOUS CIRCLE ( or should that be Vicious Cycle )



would seem the CAM CHAIN ( BSAs & Triumphs lacked this ' service adjustment required ' item ) & Auto Retard / C. B. assy ,
were at the core of the trouble . Sloppy assembly was resolved . Burnt Fingers & No Rev Limiter saw the Comat spec discarded .

This is a Combat

Because it says so :mrgreen:





And that all-important smaller-than-usual gap between the skimmed head and the ubiquitous BLACK barrels :lol:



Incidentally, I'm still under instruction to sell it :roll:

1up3down said:

Norton said that the maximum "cruising" rpm of a 850 is 5800, with the redline slightly higher

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Nortons said the redline for the 850 was the 7000 rpm red line marked on the tacho.
Along with that 5800 rpm max cruising speed.

Nortons also said max power in the Combats (750cc note, with 2S cam etc ) was 6800 rpm.
Same 7000 rpm redline.
Hands up all those Combat pilots that can reach that 6800 rpm max power mark,
but NEVER use any more than those 200 revs beyond that.
Built in recipe for a bit of an over rev there, by any standards...

Thats what these new fangled rev limiter thingies do - like having eyes in the back of your head on the tacho, so to speak ?

7000 RPM is over 4000 feet/minute with a 89mm stroke,seems a little high for general longevity.
Is it time to bump the 8000rpm thread ?

Is it time to bump the 8000rpm thread ?

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And dump those 19t sprockets they (some ?) came out of the showroom with...

L.A.B. I'm not sure of anything I say on anything Commando after you point out possible exceptions to the rule. Rules get broken and so do I of course.

I can put up my hand at back of class on, 1st week making it to pavement w/o crashing I started a gleefull passing of semi with on coming to zoom past in 2nd through the rush of 6800 to hit sudden valve float too soon afterward so thank goodness the horrific engine noise and misfire back fires didn't seize and left rpm hi enough a snick to 3rd got me around and in front of cab in time. Steel flywheel and Dreers valve kit and cryo tempering and friction coats allowed Peel to run deep into red zone now and then in tights to prove front tire not needed to steer sharper harsher. Factory Combats blow up right as they get really going good. My pure factory Combat Trixie in 2013 pissed off some 2012/13 Aprilla, Ducati GRXS, etc by not getting left very far behind in straights, only because I didn't care to run-waste her to top end of 5-10 mph higher which was as fast as those fancy pantsy riders where brave enough to take Ozark hwy. I was right on their tails though by time they slowed for corners about as fast as I care to take em on a real Commando. No one was racing just having fun fast as reasonable. Ms Peel would of left that timid corner cripple bunch in the dust after first real turn or two and of course I cruised to work as fast as these superbike riders said uncle. if ya don't spend a lot extra - better refrain as I do on a factory issue Combat.