1972 Norton Commando Roadster Combat, What makes it a Combat model and some modifications we made 

I also have a '72 Commando (Roadster, Combat).Thanks for all the details on this video. The video is a great motivator for me to get back to working on the bike. Right now it's just eye candy. 🙂I need to pull the engine and make all of these updates as I don't know what prior work was done on it. I've been planning to add the Jim Schmidt upgrades when I do that. Special thanks to everyone's comments here. Super valuable.

Hey, Jesse. Great video and beautiful motorcycle. I owned a yellow '70 Commando (70 - 72) here in the US, I sold it when I went to work for the Norton factory in England. I was working at the factory when the Combat engines were built, my job was in the Service department so I was livin' through all the problems. You have some great details and I hope you'll allow me add a little more. You note how the breather moved from the end of the crankshaft to the back of the crankcases. That was a part of a complete crankcase redesign which was brought into regular production in early January, 1972. The new crankcases had the oil pickup changes you noted and a lot more "meat" around the main bearing bores; the bosses for the engine mounting bolts were also strengthened. All "Combat" engines were built with the new crankcases. Some Scandinavian countries required "Type Approval" for a new engine; since there was no time before the Scandinavian selling season (which only lasts a few weeks) to approve the Combat engines, all '72 Commandos built for Scandinavian countries (and some other European markets) were standard engines. Also, a few British dealers were able to order standard engines at a reduced price so some were made for the UK with the standard engine. The introduction of the Combat engine as an "option" began about serial number 200900 (the first "strengthened crankcase" engine was 200001). The front disc was also an "option" but - in practice - once the first one was built there were only the very rare special order Commando that were built with the front drum brake (one exception, below). The Commando for 1972 was offered in three main models; the Roadster, the Interstate, and the Hi-Rider. There were a few "Fastback" models early in 1972, the factory had intended that the Interstate would replace it but since that model went all the way back to the first Commando i 1968, there was still a temporary market for them. The theory in 1972 was that the Combat engine and the front disc were to be offered as option equipment but that didn't really work out. Once the two were introduced, almost all of the Commandos built in early-mid 1972 were equipped with both. The notable exception was that Hi-Rider motorcycles were built with the standard engine and drum brakes (for several reasons, I won't go into here). This brings us to the details and definition of the "Combat" -- it was a performance engine option and was not considered as a "model" by the factory. It could be ordered on Roadsters, Interstates, and Fastbacks, but it was an option, at least in theory in the beginning. As you noted, the Combat engines had 32mm Amal Concentric carburetors with matching ports, a cylinder head with a milled facing surface at the head gasket that increased the compression a little more than one and a half points, and a "Two S" cam. The naming of the cam raised some issues in that the cam grind on the standard Commando cam (all the way back to 1968) was actually the "Sports" cam grind used on the 650SS from the mid-1960s. Previous Norton twins in the 60s had been 600 or 650 cc but with competition from the BSA A-65s and Triumph Bonneville TTs, they felt that they need a real performer; that's why the 650ss was born. And it's performance was way above all Norton twins so far and it's parts wee favorites of Norton tuners in the 1960s. The problem was that everyone called that cam the "Ess-Ess" cam when used in the 650. So, the factory made a decision to call the Combat cam the "Two S" and the standard cam the "S" cam. The 3S and 4S cams had already been released for use on production racers by the Norton race shop at Thruxton, soon to become the John Player Norton race team, so the denomination was consistent across the different cam types. A problem was that the "2 S" cam was not well designed. It had higher lift than the stock cam but the profile turned out to not be very good. It was abrupt at the lift transition points and the transition to the fully opened valve position. As a result, there was a very high-G acceleration of the lifters, valve train, and valves especially at high RPMs. To calm the tendency for the lifters to bounce and chatter against the cams, the spring pressure was raised. All this meant that the engines were prone to high valve wear, broken springs, and overstressed valves, springs, and valve seats. Not good. (The 3S and 4S cams -- while good for their time -- suffered from similar issues. The technology just was not well developed to reduce the stresses. Later, Peter Williams, the Norton race star of the 70s would design a cam to replace the 3S and 4S that he called the PW3 cam. It was a cam with race timing and lift but computer designed to make cam lift smoother and gentler.) But the problem has remained with the 2S cams; a number of people went back to the "S" cam; it has a much wider powerband and it's smoother, also, it has a great torque curve down low and with smooth ports, reasonable compression, and good gearing, it pulls like a freight train out of corners and that's a significant benefit with a 4-speed gearbox. The 2S is slightly more powerful at the top of the power band, but it can be harder for a rider to use it all. I absolutely agree with your discussion of the oil pickup issues on these engines. As you note with the INOA Tech Book's discussion of the problems, there are fixes and you have done a very clean and accurate job of implementing the changes needed. And for modern use, it's good to use high-quality synthetic oils (See Jim Comstock's excellent Commando oil-test videos on You-Tube) -- it didn't help that the "factory fill" oil was Castrol's recommendation of 10W-30 multigrade. We had an excited call from the Norton importer in Germany -- his dealer sold a Commando with a Combat engine to a customer. The customer came back in the next morning and said "It sounds like a gravel crusher". He had gone out to the Autobahn and rode it -- brand new -- to show his friends who lived about 100 kilometers away -- full throttle both ways. By the time he arrived home, it was making noise in the engine. The importer got an oil sample and when we analyzed it, it came back as a straight-weight 8SAE oil. ALL the multi-grade properties had disappeared in 200 Km/ 120 miles. The owner got "Superblends" and we learned a lot about multigrade oil. As much as for public image, the Combat engine was dropped about serial number 211110, mid autumn, 1972. We knew that we'd fixed it but too many potential buyers wouldn't trust it so the decision was made. BTW, my Combat 750 (serial 2096**, late June, 1972) came with an oil filter. It was listed as an "optional extra" but -- like the big box taillamp -- it was included in every "NAS - North American Spec" Commando at the time; that's what I got on the Private Export Scheme purchase, delivered at Andover. I know that quite a few built after did not have them, but some earlier did. I rode that motorcycle for 8000 miles in 9 months, then it rolled back into the factory and came out again as an 850 Production Racer, with a hand-built John Baker engine built up from left-over prototype parts, in every spec a "Combat 850". As far as I know, it was the only 850 Production Racer built at the Norton factory (there were some built and raced at the Thruxton race shop and then sold to the public, but mine's the only factory one). It may be for sale soon - contact my widow. Keep up the good work. I've subscribed. Thanks, BH

just picked up a 69 commando for a thousand dollars, shed find rusty and rough but good bones. Im stoked. tearing it down

Bought my first Commando in April '73, the staff at the dealer said the same thing as you guys, Combat cylinders were black, all others silver and they were about 5 more hp. Mine was a Combat in black, titled as a '73 in Ohio. Yes they were a warranty disaster, mine hand grenaded at exactly 141 miles on the very first day i had it, punched a hole through the case. I did not exceed the RPM limit when it happened or all day. The dealer picked up the bike and had it a month to repair. Whole assembled engines were not available from Norton, all parts were ordered individually. The cases were replaced, the new ones were blank where the serial #'s are. They said the crankshaft sheared in half on the drive side main journal. The dealer must have assembled it with the new Superblend bearings and great care, because after the 1000 mile break-in period, i never got beat on the street, it was a 12 second bike!

10.31.22. The high pipes on that bike really sets it off with that yellow paint job❗️👻🎃

Hi Jessie. I enjoyed your video on the Combat Commando. I've owned a 72 Combat Commando Roadster since 1984. The previous owner had blown it up and fortunately did not do the repairs himself instead had a competent rebuilder do the work. All of the research that I've done over the years attributed the Combats problem as being due to the crankshaft flexing during overrev situations causing the crank to bend and destroy the bearings. The problem as I have read was solved when they fitted "Super-Blend" bearings that are barrel shaped to one side of the crankshaft. When I bought my bike it came with a box of the old parts that had been replaced, complete with broken bearings and such. I look forward to watching your other videos.

From what I remember reading at the time, following the problems with the Combat engine, increasing the capacity to 850 (actually 828cc) was Norton's solution to getting more performance out of the Commando without over stressing the engine. I had a new mk 2a in 1974, which was a lovely bike to ride, but had its share of vibration-related problems, including dumping the baffles from one silencer on the M1 at midnight (that made for an interesting ride through central London in the early hours), and stripping the threads in the exhaust ports. I only kept it for 18 months, then sold it and bought a car. When I see one now, I still feel nostalgic, but my Triumph T140V is a much more practical (and affordable ) classic to own.

Gorgeous resto. Got a '73 Roadster, myself. I installed the CNW reed valve breather, and it made a surprising performance improvement. But, I was hoping you could mention the source for that little plastic fairing.

Was a mechanic for norton agents in the early seventies. Did several main bearing replacements with superblends on combats...some still within warrantee. Suspect they got thrashed badly before failure but never saw thrown rods like the atlases

My Combat 202592 left the factory marked December 1971 and shipped straight to the US East Coast but was the full combat spec. Now re-imported back to the UK and wearing a 71 plate totally rebuilt and after running in was lapping up to 100 mph at 6500 rpm at Cadwell Park in June. Although combat skimmed 'C' head I am running a thicker base gasket to give the valves a tad more clearance and an easier kick. Brucebear thanks for the excellent information

I bought my 70 commando S model in 1977. Its been a long hard and as i say , just a few more thousand dollars and ill be riding.

Fantastic channel love your passion for classic British bikes. Grew up with the Norton commandos and was fascinated by them. I run modern triumphs and wish I had the knowledge to own an old classic.

I bought my combat roadster new in Oakland Cal. Several months later my dealer called and said there had been some problems with the main bearings. He told me to come over and pick up my new ones....free of charge. So I bought a workshop manual and started my learning curve. I must have done ok because there have been few problems with it. I was 22 & in the Navy. BTW its the purple one & I still have it.

Norton commando rear mudguard in green what great styling an almost perfect bike.

Best feature of Norton commando stylistically was for me the rear mudguard so distinctive.

Very cool bike.

I had a 72 Combat I restored years ago. It seized twice due to oil starvation going up long uphill stretches of road. I wish I new the CNC fix you mentioned. I did put about 13000 miles on it before I sold it.

Lovely bike in.yellow ,handle.with care ,mainta.inence is es sen tial on time or early.to.ensure longevity and don't over rev

Because of a high speed engine seizure at 2000 miles Norton removed all the 'Combat' stuff out of my 1972 750 Interstate , including the extra performance I'd paid for out of my engine under warranty.

Back in the 80s I was a mechanic at a Norton, Triumph & BMW dealer. I did mostly British work and I hated to see a bike come in with that Harley rear rim. We changed tires by hand (no machine) and those tires had super stiff side walls and the rim was extended making them a real bear to get on and off.

How do u build a modern day Norton race motor for flat track?

My 72 Combat Roadster was the metal-flake orange you mentioned. I kept it all stock. It was definitely difficult to stay within the speed limit with that bike. Are the silver fork yokes the stock color? I can't remember what color mine were. I know that my 71 Roadster has black yokes. The 850s all have silver yokes. Love the SS exhaust system!

i strongly recommend the motor is taken beyond 5K rpm, in top gear.

I have a 72 combat that I bought from a friends widow. Walt bought it in 74 and rode it a little. The PO cut the rear frame loop off right at the shock mounts and put a sissy bar and diamond seat on it trying to chopperize it. Luckily that is all he damaged. Walt started taking it apart (but not much) in 76 then it sat in his garage until I bought it. I have all the parts and the engine turns over but EVERYTHING is in need of rebuilding or replacing. Now that I’m retired I have plenty of time but only about a $17.00 budget so I guess I’ll sell some other project bikes that are taking up space. Just subscribed to your channel and watch a lot of others. Where is the best place in the States to get parts?

I had a 1972 Combat Commando back in 1985 +/-. It had a Barnes spool rear hub with a Hurst Airheart disc brake set up. I had it out one afternoon honking the living snot out of it. I stopped and looked down to see my right shoe covered with oil. I checked the oil and it still had some so I headed for home. It started vibrating like a jack hammer and eventually stopped running. After a long push and a truck ride home I find the main engine cases both L & R with huge cracks and the broken pieces sitting loose directly below the cylinder. In both front and rear. I took it to Pokes cycle in Seattle and Ross said; "Competition Blow". Is that why it came apart??? oil problem???

Hi i raced a 72 combat red lined 7000 never had problems.. superblends does it

where did you get that nose fairing from ?

Jesse, I have what we believe to be a 1972 Norton 750 Commando but we have some questions about a few of the features on it and whether or not they are original or parts/features from different year models. Any chance we could chat or exchange emails so that I could pick your brain a little for some Norton facts?

Lovely bike , just wondering what the advantage is of fitting a 16" rear tyre .

Looks a little strange with the SS pipes. Combat nicknamed Hand grenade

I have a Dunstall Norton. It needs love. Best place to buy Dunstall parts and parts in general ?

Any chance you can sort your videos into playlists 🤔

It shifts on the right,,right?

The hi rider Norton was the ultimate bad taste option similar to the beauty.mods to bsa rocket three giving it only the tank capacity to get you down to the shops and back the bigger tank was much more.practi cal .and as for the high bars you knew how a government flag felt .blowing.im.the wind all day long

I have a strange question for you guys....with Nortons making more power and being faster than triumphs, as well as Norton having the two versions of the featherbed frame, why did people build Tritons? It seems backwards.

The normal engine had problems overall and does last about the poor components. The combat was a joke and got more problems. I loved my Commandos for the pleasure to ride but problems at all. Traded for a CB 750 and the world was allright

English speakers always love to hear themselves talking and talking and talking...🥱 I wonder how you make your children...😂