Combat Vs 73 Commando

Looking at a 73 Norton 850 or 72 Combat.
The issue would be which one is it that a person should go for when looking for highway reliability with top end speed, and around town traffic scoot. This will be a first bike for me hence the question. I would appreciate any opinions to be supported as well please.
Thanks for your time.

From creeping stop/go tight city operation to wild top speed flings Combats top Norton charts. Need two mirrors and maybe signals added is all. More Combats made-sold than any other year too. They have innate factory dangers so must be gone though if not already, but then as good as any Cdo for endurance, unless you can't use discipline to keep the rev's to redline as there is no drop off in pull, like 850's, just pulls harder till it blows up or ya back off or up shift to 4th.

BEWARE, Combats can rush you right straight into HINGED HANDLING in sweepers so creep up on that to understand it and avoid it as takes a bit or held powered lean to begin mild onset > then all hell can break loose like a fish flop off the dock SPLASH> There are solutions galore for this.

Play with tranny sprocket to get the long legged yet still spunky torque thrust.
I like 20T on non hot rodded Combat, which is still under 13 sec 1/4 mile, and
21 on lighter or hotted up a bit Combat. Should be good over 120 mph when dialed in.

Cream of the Crop to me.

Doesn't matter. Find the best Norton you can and enjoy it.

Are you sure you want a vintage Commando as your first bike? I am not trying to put you on the defensive, but what is it that draws you to the Commando? I think therein lies the answer to your question. They will both potentially be great bikes. Are you going to want to keep up with modern sport bikes? Are you inclinded to enjoy problem solving and wrenching on your own bike? There are a number of guys who have given up fighting tuning problems on their Combats and have therefore detuned them so that they are easier to deal with. If you fall into that group, I would just buy the 850 to start. Not that the 850 is a pig, but they seem to have a bigger sweet spot.

Russ

Having owned several of each the 850 is more reliable, the biggest problem with a &50 is the Barrells and how many times they have been "over bored" as due to the fact that all 750's have a flange mount they gey very week after several overbores have the reputation that with a decent compreion ratio [over 9-1] 750s can lift the Barrells off the cases [explode], as 850s have the 4 main bolts coming thru the barrells it is a lot stronger- you can add a cam and compression with out it becoming a hand grinade.
Al

My first cycle after 30+yrs too scared in big city events to ride, was a Combat with bent crank and cracked cases that with online hand holding and manuals and vendors advice became a sports bike hunter and off road play thing. Hop on an 850 vs 750 and the sense of 850 sluggish steering is noticed and also the pull drops on 850's about the time you start to grin - not so the handy Combat. Combat BOMBS are the worse creation and fuk up Norton ever did and essentially brought it to its knees to fail a few years later. The horror tales are all done now and Combats pretty easy to make as enduring as 850's while leaving them behind when push comes to shove and just as comfy soothing for Interstate travel. Guess which model came out with the longest range 6 gallon tank hehehe. The real weak link in all Cdo's is the drive train and over reving.

I'm with Hobot and another combat owner. The 850 is probably a better cruizer while the combat is a better performance machine. I prefer the performance so don't mind the less reliable. As a first motorcycle, suggest a Honda. There's a lot of education ahead of you diving first time into a Norton. However the journey has it's rewards.

What happens when you combat an 850?
Cash

The 850 has a broader power band and more low end torque. It's perfectly content plodding about at 3000 rpm in top gear and still offering good throttle response. The Combat motor comes alive at 4000 and revs effortlessly all the way to redline. Well suited for high speed highway riding. Either one could be a great ride, I'd make the decision based on overall condition and not by the motor size.

Welcome to the wild side.

cash said:

What happens when you combat an 850?
Cash

Click to expand...

The same thing that happens when you bore a Combat out to 77 mm!! :lol:

Is anyone running an 850 with a Combat cam, twin carbs and 10-to-1 pistons or a skimmed head with valve cut-outs?

My RH10 850 with a 16-inch rear tire, single Mikuni and an extra fifty pounds of bling is almost as quick around town as my '72 Combat with 932's and ultra-tall gearing. Despite the single carb and the chopper avoirdupois the RH10 seems a lot quicker than most 850's I've ridden.



Tim Kraakevik
kraakevik@voyager.net

I "think" I have the best of both worlds.

I have a 73 850 that has a Megacycle 5600 new cam installed, higher lift than stock cam, oversize valves, 9 to 1 compression, with Jim Schmidt's twin 32mm flat slide carbs, and a 20 tooth countershaft.

Ideal. 850 grunt in the lower rpm range and strong cam and carbs rev and pull hard all the way up.

although mine is still not running yet (due only to me not having time to work on it) I vote 850. the stronger cases and through bolts make for better start point. We all work on them and dail them in to suit ourselves, check out JSmotorsports products. Cj

"by 1up3down » Thu May 12, 2011 4:59 pm
I have a 73 850 that has a Megacycle 5600 new cam installed, higher lift than stock cam, oversize valves, 9 to 1 compression, with Jim Schmidt's twin 32mm flat slide carbs, and a 20 tooth countershaft.
Ideal. 850 grunt in the lower rpm range and strong cam and carbs rev and pull hard all the way up."

Is anyone running an 850 with a Combat cam, twin carbs and 10-to-1 pistons or a skimmed head with valve cut-outs?

Click to expand...

Yes! I'm not sure what you mean by 10-to-1 pistons. The compression is obtained with the skimmed head.

My bike runs twin 34 Mikuni's and the head has oversized valves and some port work.

There are many competent Norton mechanics and owners on this forum.

We don't know what your mechanical experience is, so that's what is in the minds of some of those posting in this thread. These bikes in stock form require more maintenance than others; once they are sorted out, the right parts upgraded, then they are reliable, long legged, and sexy.

Not that I am volunteering anyone's assistance, you can ask . . . . if you identify one of the board members near you and you are able to enlist their advice in your purchase, that would be a wise way to start. Then if, they are willing and you can afford to have them do, or help you with, any deferred maintenance and in the set up and sorting out your new purchase, then heck ya, go for it.

PS, '73 750s are the best :lol:

Ron

Years ago 10-to-1 pistons were available for standard Commandos with deep valve pockets in the pistons--haven't seen them lately--I had a couple of sets--from a major Italian manufacturer, if I'm not mistaken



Tim Kraakevik
kraakevik@voyager.net
'72 Combat, '74 RH10 850

Yes I think "Venolia" used to make a few different High Comp Pistons for 650 and 750.
AC.

You can get them here....
http://www.jsmotorsport.com/products.asp

In the 70's I ran a MK11 850 with a Combat cam, standard Amal 32s with velocity stacks and rejetted to suit, and a two into one exhaust. With standard 850 gearing (21 tooth) it would pull well at lower speeds but would pull harder at 4500 rpm to the redline. On the open road once with my then girlfriend on the back, we were moving around the traffic in company with a Kawasaki Z1, also with a (male) pillion. Pulling out to pass at 60mph with a change down to third, he was pulling away from me very slowly. This happened a couple of times and when we stopped for fuel, the Z1 owner couldn't believe that the Norton was so close to matching his performance.
My suspicion is that when it comes down to acceleration between the 750(including the Combat) and the 850, it mainly comes down to the standard gearing of both. Two teeth difference on the gearbox makes a hell of a difference with all else being the same. Up until recently, I'd been running a 23 tooth sprocket on my MK1 850 and then swapped over gearboxes while I recondition my original gearbox. This box had a 21 tooth sprocket on and the difference was considerable. It felt much revvier with the 21 tooth. I have since gone to the 22 tooth as a good compromise.

PS, '73 750s are the best

Click to expand...

Another has seen the light! ( I have two MkV's)

As to the Hi-comp (domed) pistons, what do our engine building gurus think about domed pistons vs. milling the head to increase compression on Nortons? I was always told that the Norton head design was much better suited to a flat top piston than a dome.