questions about 72 Commando

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Hi Dave,
please let us know if you bought the 72 commando.
If not , then Why ? & how much did it go for.
The previous writer was a bit negative I thought as by now all the combats will have had the engines sorted out & most
people only found out the combat was over stressed & prone to blowing up when Norton announced the end of combat production.
My commando was made in sept 72 but was not combat spec.
Its been pretty reliable for me over the last 37 years.
Wish I could say the same for my right knee.
I remember as a kid riding past the Norton factory in plumstead, London while on my pushbike & wishing that one day I might own one. Well ive not been let down as ive owned a Norton since I was 16 & dont regret buying one at all.
Cheers all
Don
 
I ended up passing on the blue one - decided the money it went for ($4150 I think) was a bit more than i wanted to spend based on the blue color, combat motor, fiberglasss tank and the mileage. I am going to keep looking. I think I will try to be patient and hope maybe a 73 or 74 roadster in black or red comes along locally. Considering an old airhead as well for a "hobby" bike - trying to be patient for when the right one comes along. Michigan's economy is a train wreck so i think there is reason to believe there may be a deal out there somewhere. You know how it is - you know the right motorcycle for you when you see it.

Amazing you can remember riding your bike by the factory as a kid! Ever read the Peter Egan column about him wandering through the abandoned Norton factory? Good reading.
 
Airheads are also good hobby bikes, a few guys have them too on this board. I have a couple of Chinese copies of early airheads, for some reason I was a bit bored with the BMW versions.
You should be able to get a good deal on a Norton right now as folks are getting stuff out of thier garages that they don't really use. I've seen a few go for quite reasonable prices but there are lots of bikes here in California.
 
I bought a new combat commando in 72. It had the superblends. I drove it hard always. I had to replace the cam because the original had the keyway cut in the wrong spot and you couldn't time both cylinders accurately. A vernier sprocket would have worked also. I never had any other problems with it. I've also had several second hand 72 combats and they all ran strong and hard without problems.
 
I wonder how many they actually built before they discovered the problem? I know they got on with fixing them as fast as possible after that.
Norton was not alone with problems like that, BMWs snapped the front of the crank and had the same main bearing problem, also resolved with superblends.
At this point I've known a number of folks who got years of service out of superblend Combats.
 
Yeeees RennieK,

that was the input I needed!
I am just refurbishing my Combat engine, and I don't want to go with a decompressing plate under the barrels!
How many miles did you get on yours?

Andy
 
I've posted this before but thought I would post it again.
questions about 72 Commando
questions about 72 Commando
 
I would also be sure to have your crank checked for any hairline cracks, The motor I tore down had a hairline crack developing right at the rod journal. You never would have seen this without magnafluxing it, (I think that's how you spell it.) Mine has turned out to be a very stout motor with loads of down low torque and pulls hard all the way through the gears, Although I don't think I have ever taken it much above 6,000 RPM. I used the Megacycle 560-NR cam that has the Norris profile, Not too radical so it's nice on the street. But really pulls like a freight train from 60 to 90, Don't really know just what she will do yet. Chuck.
 
Andy said:
Yeeees RennieK,

that was the input I needed!
I am just refurbishing my Combat engine, and I don't want to go with a decompressing plate under the barrels!
How many miles did you get on yours?

Andy
Click to expand...

Hi Andy,

Just went to the garage and checked my combat. It has 46,600 miles on it. I rebuild the whole machine in 1998 at 20,470 miles so roughly 26,000 miles I have first hand knowledge. The only failure has been the left exhaust valve guide went loose. Just did the winter check and needed to replace the bush on the layshaft first gear. The speedometer reads about 5 mph higher than actual speed. I've had it to 110mph indicated. Surprised my friends son who was riding a Yamaha R1 in our group on the way to Laguna Seca. That's the machine in my avatar to the right.
 
I can't remember how many miles I had on mine. I owned 7 Nortons in the 70's and 80's, one 850 and the rest were 72 or 73 750's and mostly combats. I still have one of them that's been in storage since then. I bought a second 72 combat recently too. I found the power band from 4500 to 7000 rpm although I always shifted before the power band cut out (or the valves floated or crank blew?) There were times I wouldn't shift till 7500 but not too often as I was pretty religious about shifting at 7000 specially in the lower gears because you new the next gear was going to propel you that much faster!.

That is sure a depressing article. My little circle of friends back then had heard about the bearing issues and we all made sure we had superblends but otherwise were oblivious to bottom end problems. The points plate was a known issue but not too expensive to replace. It was more a point of musing because you understood the power of the engine.

I love the 10 -1 compression, 2S cam and 32mm intakes and wouldn't want to step backward. I want to do the crankcase mod as outlined at "OLD Britt's" Here:

http://www.oldbritts.com/39_300901.html
 
RennieK,
I have a 72 combat #209199, production plate dates it June 1972.
I did not ask previous owner if bearing mods were done as I did not know enough at the time
to ask the right questions.
I purchased it July 2004 w/ 8050 on the odometer.
It has 9200 miles now.
I've enjoyed two summers avg 600 miles a season w/o incident.
How do I tell w/o ripping the motor apart if the newer style bearings are in my engine?
Would a June 1972 bike have had the newer bearings by now?
I keep her between 4-5,000 rpms and it is entertaining enough for me.
You mentioned that new bearings were installed at production w/ one of you combats.
What was the production date of yours?
Thanks,
Marshal
 
The one I purchased new in 72 is long gone now. I think my bike was about the same vintage as yours but there is really no way to tell for sure without getting inside unless some of the serial number guru's have figured it out. If you can keep it below 5000 I wouldn't worry about it, just keep it tuned up and topped up with quality oil. Eventually you'll need or want to get inside and you can address the issue then.
 
RennieK & Cookie,
thanks for the responses.
That is a relief knowing I don't have to get in there at least for now.
I was wondering if I ever have the head off or timing side open can you see the bearings
w/o splitting the cases?
Thanks,
Marshal
 
According the the International Norton Owners group tech digest the switch to superblends occurred at serial # 207197 and the first detuned post Combat 750 at 2111110. My bike is serial # 2112** and has an August 72 build date, late in the 72 model year. The head is not marked with a C but it has 32 mm carbs.
I haven't been into the cases yet to confirm the superblends. Is it possible to pull the crank seal on the drive side and determine the bearing type.
 
According the the International Norton Owners group tech digest the switch to superblends occurred at serial # 207197 and the first detuned post Combat 750 at 2111110. My bike is serial # 2112** and has an August 72 build date, late in the 72 model year. The head is not marked with a C but it has 32 mm carbs.
Click to expand...
Im very curious mine is 207072. Im in a complete overhaul and will try to let you know what the bearings are for that serial. How do i tell if they are superblends?
 
Is it possible to pull the crank seal on the drive side and determine the bearing type.

I think if that were possible the word would have spread like wild fire. There can't be more than a 3/16th gap to peer into and I'm not certain but I'd think the lower race would be what you saw.

How do i tell if they are superblends?

Superblends have barrel shaped rollers, not cylindrical or ball and they are held in place by a distinctive brass cage. They have a cousin which uses a nylon or plastic cage which are the next best thing.
 
Marshal -

The way we were chasing Suzuki-man last Spring... if they weren't Superblends it definitely would have blown up. :)

Russ
 
Happy New Year Russ,
yeah, I think if it were going to blow that ride we did last April would have taken her out.
That guy on the tripple 500 Suzuki was really flogging it.
Every corner I approached I could smell 2 stroke oil.
Like when my kid mixes up the ratio wrong on the weed wacker. :lol:
I felt like we were qualifying for an AMA vintage race :shock:
Another rider posted that the 207... range was the change over to superblends.
Thanks for posting this!!!
I'm a little relieved I don't have to get into the motor now.
I have the trans to do when it gets a little warmer.
I feel prepared from all the responses to my questions to tackle it in situ.
I had AMR do a seal mod for the spare trans cover I bought.
Com' On warmer weather!!
MArshal
 
maxxfli,
how did the factory detune the combat?
Was it just a matter of placing a thicker base gasket to lower compression?
Or did they stop shaving 40 thous. off the heads?
Without a C stamp it sounds almost like the 850 head w/ the 32mm carb ports.
Thanks for posting the tech digest info as I posted to my friend it was a relief being above 207....
for now any how :shock:
Love to know what you find inside your cases when you get to it and report back.
Are you definitely the 1st one to take the engine apart?
Marshal
 
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