Combat?

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radiofun

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I'm looking at a 750 commando with parts from 72 and 73 supposedly. Front brake is not disk. Were drum brakes used on the in 1972, or is the bike likely a 1971, or earlier? How can I tell if it has a combat engine just by looking at it?
 
A combat head has the letter "c" stamped into it underneath the head mount.
The serial # of my combat engine is 202717.
 
Combats also have 32mm carbs. '72 had a disc brake, '71 did not.

Russ
 
Combat have narrower gap at head/barrel fin seam and the breather hose comes off rear bottom of engine cases and black barrels. They also have no drop off in power band in lower gears, especially after 6800 rpm. Would have to mic valve lift to verify the 2S cam inside. A compression check on healthy Combat is near 190's PSI.
 
VIN on this bike is 235,312.
Click to expand...

That VIN number would indicate a late '73 750. Is it this the number on the frame tag or the number on the engine cases? If it is a '73 motor it could be a hi-compression or low compression but would not have the Combat's 2S cam.
 
I remember walking into a Norton dealership in 1972, and actually saw (?) parts on the shelves and parts arriving on a regular basis. So, if you owned an early 72 with the new style breather, etc. it wouldn't seem beyond the realm of possibilty upon seeing this new Combat model come out, you might just order up the whole works, have the shop put the Combat cam in, and maybe even install a new-fangled disc brake. I was over at Baxters a few years ago, and an owner of a new Bonneville was installing a very pricey big-bore kit prior to delivery, so I know stuff like that goes on in all eras. My Combat (201390) has been changed to a drum brake. I love the looks of them, had a nice wheel and fork leg, so I made the switch and saved all the stock parts, if I want to switch back. With RGM shoes, and a careful arcing, it's not bad.
 
Last 750 made is 230935.
Mk.5, breather on back of timing side case where the magneto used to be years before.
32mm Carbs., rest of engine standard.
Combats, I believe were 1972 & had disc front brake.
 
But if it has a 2xxxxx #.... it had the 72/73 combat breather crankcases.
Most NONcombat tune 72's 20xxxx such as hi-rider were drum brake. Not sure how interpol were treated, since none came to the USA.
 
To me and many others the Combat is the cream of the C'do crop but it started as a very ugly duckling that takes devoted owner to bring to full Swan powerful long flights. Here's the history to laugh till ya cry ... Can pull under 12.5 sec 1/4 mile and lug a tall gear to cruise at 80 mph all day long near 4000 rpm and smooth as any and just for extra laughs guess where the 6 gal tank 1st showed up on... BTW standard factory manual has the specifics on engine part measures to check between standard and Combat.

old-combat-article-t8728.html
 
Ron L said:
VIN on this bike is 235,312.
Click to expand...

That VIN number would indicate a late '73 750. Is it this the number on the frame tag or the number on the engine cases? If it is a '73 motor it could be a hi-compression or low compression but would not have the Combat's 2S cam.
Click to expand...

The 235*** numbers were supposedly used for the short stroke 750s and also some '74 850 Mk2A models, and I believe one of our members also has a standard stroke '73 750 with a 235*** serial number so 235312 shouldn't be a Combat model as they were all pre-211110 numbers.
 
A Combat is as Combat is assembled so regardless of the factory case numbers it could still of been reconfigured to Combat innards, which means 2S cam, ported shaved head and pistons that stick up .050" above barrel surface, like other 750's I just learned.
 
For those who won't listen, I'll say it again, but louder :
NO STANDARD PRODUCTION 750 OR 850 HAD PISTONS THAT PROTRUDED ABOVE THE BARREL TOP FACE !
I'm going to ask nursie for another pill now.
 
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