in over my head again

long time reader, finally getting around to the introduction. first things first:



'72 750. possibly combat, but i haven't seen the head stamps. will measure the cam when i get to it.

forgot to take a photo before i started stripping her down... got all the parts on the work bench you can't see. she needs lots of lovin': most of the rubber is crap, lots of surface rust and grime to take care of, front break lever assembly is garbage, lots of corroded bolts, and who knows what the insides are going to look like. i'm pretty sure i've once again bitten off more than i can chew, but it should be an interesting process!

the goal is to get it stripped all the way down, separate the usable from the undesirable, and then get it back up and running asap. i want to build a functional road bike, not so much a 100% faithful restoration. function > form, and i'm not much of a purist when it comes to classics.

...actually, i wouldn't mind putting a jap fork on and some sort of disc-brake situation in the back. suggestions welcome!

cheers everybody - and thanks for being such a great resource! this forum is great.

Matt P.

Looks like cream of the Norton crop Combat and should be if you see oil breather baffle down between cases and tranny. Spanking sports bikes became my hobby after my first rebuild and fork solutions so don't encourage assian forks or anything else to get best there is in the fly flinging department. There are a number of fork options within Norton word, the cheapest, to me may be the best-est but would be great if a hot shot rider tried the whole range, factory to foreign forks.

Once riding be weary of brake fluid leaks blown away till suddenly no brake.
Do not use comma shaped oil hole pistons nor Al gasket if found.
Best wishes the swing arm spindle is still accessible or serviceable.
Adjustable isolastics way worth the cost in the long runs.

hobot said:

Looks like cream of the Norton crop Combat and should be if you see oil breather baffle down between cases and tranny.

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NOT TRUE all 72 and 72 750s had rear breather BUT not all were combat.

If we tell him enough times, it's bound to sink in, sooner or later. :wink:

post87502.html

L.A.B. said:

hobot said:

Check for the low down rear breather hose take off, only Combats had them.

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So, what breather did the standard models have?

To my knowledge, no alternative breather arrangement was used on the 750 models from early 1972 to the end of 750 production in October 1973, and no alternative 750 breather parts are listed in either the '72 or '73 parts books.

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OK Windy then may also look to see if head/barrel fin space is narrower than the rest to indicate a CHO milled down head. I followed DynoDave's review to check cam profile to verify my Combat was Combat to the 2S cam and was installed
right. Another way to tell is setting ignition to 32' degrees, Combat will break you kicking until backed off near'r 28' full advance, like with a new Boyer analog injury taught me on newly usable fractured R knee. Compress test also may show its up near 10 CR. Did the non Combat '72's come with black barrels Combat had, but could of been painted anytime in past. Also ride test in 2nd to 7000 rpm, it should kick in another pistons worth of cam power and lift fork to full extension if not tire off surface passing through 6800 rpm threshold I found. if it tends to detonate on 87 octane w/o alcohol is another Combat feature mine had.

hobot said:

way to tell is setting ignition to 32' degrees, Combat will break you kicking until backed off near'r 28' full advance, like with a new Boyer analog injury taught me on newly usable fractured R knee.

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Obviously not the preferred Combat detection method...

Obviously not the preferred Combat detection method...

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Yeah, I'm newbie to this forum but not to Combat learning curve balls others may now avoid. It also taught me the only use of a timing light is after timing dialed in by pure feel, adv till kicks back then retard till just don't. R knee hanging free by skin only happened .15 sec after avatar shot was snapped. Practicing what I preach in clinic the dangling knee was good enough to kick 3 wk later but re fractured some on locked knee impact with lift off down a slope, squirmed in pain for 10 min then eased up to gimp off as prior so was actually elated my DIY
process was working and forgot about knee in a few months. Re broke it by a few other animal strikes but didn't worry about future joint replacement, got stronger
each time and didn't fracture on goat strike last summer with bike landing on it about 30 mph.

hobot said:

got stronger
each time and didn't fracture on goat strike last summer with bike landing on it about 30 mph.

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Can't say the same about the goat. :mrgreen:

I didn't know if mine was combat either, then LAB told me that in'72, only combats had the disk up front, and the black barrels. When I changed from a stock headsteady to the Dave Taylor (he should be knighted, dontcha think?) one, I found the "C", in about 24 point gothic typeface, right between the headsteady mounting holes. Nice looking Combat you have there. I went the same way with mine, no attempt to make a museum piece out of it, just something that runs-and stops as good as it can. cheers, Don

DonOR said:

I didn't know if mine was combat either, then LAB told me that in'72, only combats had the disk up front, and the black barrels. When I changed from a stock headsteady to the Dave Taylor (he should be knighted, dontcha think?) one, I found the "C", in about 24 point gothic typeface, right between the headsteady mounting holes. Nice looking Combat you have there. I went the same way with mine, no attempt to make a museum piece out of it, just something that runs-and stops as good as it can. cheers, Don

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Front ends got changed out, especially after accidents so the disk isn't the most reliable indicator. While I doubt someone would stamp the C I wouldn't put it past some people. Intake size probably is the easiest to identify.

hobot said:

Yeah, I'm newbie to this forum...

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Hobot, I have grown to love your....ahem....entertaining posts. However, at 3593 posts (and counting), I would hardly refer to you as a "newbie" :roll:

A good starting point to identify if its a combat would be the engine/frame numbers. Combats started at E/N 200922 and ended at 211110. At least this way you will know if it started life as a combat.
Cheers
Bazz

1970 Bonneville
1973 750 Commando Roadster
1979 BMW R100S
1993 Harley Dyna Wideglide

Hobot, I have grown to love your....ahem....entertaining posts. However, at 3593 posts (and counting), I would hardly refer to you as a "newbie"

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Like they say, the pen is mightier than the drill.

tag this Ozarks ChooChoo Bluegrass Rock Ballade Blues Booggie i wanted to Norton to Friday but must wait till next for Trixie 3 yrs in 4th recovery now.
[video]http://www.youtube.com/watch?v=r1yqgQv4gb8&NR=1[/video]

1999 I lost a week of conflict moving to Ozarks and no place to work yet, went out for used mower to find a winter stored well cared for hard used Combat, to spend last of my reserve$ in scared confidence I'd make it in middle of nowhere paradise. New Year's eve Y2K EOTHWAWKIt @ 6 months with 14 leaks
and some smoke I let pre-Ms Peel Combat hair out in best Mt' twisties trying to break it before total go through, diving into a bend near sunset in 1st laid
full over the bugger passed through 6800 rpm and lifted its front, snicked 2nd and held on a fling the other way - passed through 6800 and the bugger wheelied sideways against the centrifugal force - I held on to 7200 and was so sold down the Combat river I ain't surfaced for air yet.

Yoose guys missed over a decade of the hand holding to horrors experienced and shared on stuffy ole INOA forum, proper knowledge NOC list and free for all Brit Iron list. Got boo'd off of INOA, NOC shut down members only I'd not re-upped yet and too many migrated off BI or got killed cycling or just died to be as pub like club as used to.

I feel guilty to take so long to recover cycles but no longer want to rush ahead to some new hard fate or freeze hands in the cold seasons as I once did to ride, nay live on a Commando - 20'f crisp to 31'f sleet to warm thunderstorms at night feeling like a b/w Lassie episode, moon light streaming through cracks in angry clouds - tree awning as leaves and limbs broke off in path... not sure if still un=broken in new bike was going to keep going with un-taxed moonshine on board 30 miles from home.

I have been reduced to raging infant throwing tools parts and running out into the night screaming/crying in frustration and failure to elated heights so fast I literally out ran my fear factor. Whats it like for you'all?

hobot said:

Whats it like for you'all?

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Its all good Steve. This commando owner/rider does all he can to keep his cool. Not that easy with some of this stuff, but.... I spend my work days with some very irrational machinery. Some of the mechanical stuff I have to deal with in a vain attempt to make a living makes maintaining a 40 year old commando seem like keeping an old schwinn on the road. I used to rage, swear, throw wrenches thru drywall, but no more. Trying my best to keep the blood pressure low. That way when I'm out for a good ride, and the shifts between 2 and 3, and 3 and 4 almost pull me off the handlebars, I know its all worthwhile, and worth staying cool. Cheers, Don

Don, may I mature as well as you are, fates willing. I have lost the pleasure to ride care free, I know I can not protect myself even if I behave myself. I don't need nor want a break from work, don't really have enough of it in spells now. I'm a last resort Dr. and fix em routinely so that's always a high with audience.

I used to think, love the one ya riding if not riding the one ya love. Not me no more, if not a Commando or flying carpet I'll take my appliance cage and stereo sipping coffee. I will ride again, through thick and thin but imagine the creepiness as image-in=ation sees deer eyes in every piece of reflective foil in the grass and leaping forms in bushes mail boxes and shadows, so to out run that fear takes 80-85 after dark, its living to the max but its not exactly relaxing joy ride.

Twice almost died on the spot, once by my ignorant hand and once out the blue both hurt like lightening striking brain. Trixie and Peel both take me over my head. and heels.

Bazz said:

A good starting point to identify if its a combat would be the engine/frame numbers. Combats started at E/N 200922 and ended at 211110. At least this way you will know if it started life as a combat.
Cheers
Bazz
snip

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200205* is the lowest # combat I have seen.
Based on the mint condition of the hardware and all parts, I believe I was the first one to open the engine up . (early 90's)
It had ALL the classic combat engine components on a pure stock bike. In fact I believe the engine cases were from the same molds since they had identical cosmetic mold defects/characteristics as my engine .... 202206......another engine in between these did have different features

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

Its was DynoDaves hand holding and cam reference charts that let me dial gauge the valve lift to determine if my Combat was down to the 2S cam, and was.

Here's another down and dirty thing to measure for more evidence.
In the absence of manufacturers quoted figures expect the
following pressure from different Compression Ratios:
6:1 88-118;
7:1 103-147;
8:1 125-162;
9:1 140-176;
10:1 162-191;
11:0 176-206.

Another meaner way is follow Boyer instructions and set to full 32" advance, duct tape kicker knee and angle - then try to kick start it.

Two Combats 203xxx and 206 xxx
200 922 - 211 110 = -10 188

hobot said:

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Love that photo...

Sorry it happened, but it's a cool (pardon the pun) photo.

Yes its pretty intense visual of how close I've come to my own photo desires more than once or twice. Taken I'm told at a Harley party that yearly burnt up some non American brands but eventually shut down when peoples cars and tour buses also lit up in later too wild of gatherings. Was my avatar until Comstock mentioned its flash back reaction to his big shop fire. Back in days when a crappy Cdo wasn't worth a Harley exhaust and muffler.

My sense of self worth spiked up greatly after first Cdo hand holding rebuild soup to nuts, then my second Combat blow ups and animal strikes to not even refer to manual, till now a 6 yrs of Peel complete modifications and 3 yr since Trixie's last rod bolt let go - I've got to open manual and filter through its errors for guidance of part sequences and clearances. I've broken a number of pullers and ruined faces of big hammers and drifts and lost a few spanner jaws torquing up properly, crank to spoke nipples. Never had the happen from tractors, trucks to bulldozer and crane repairing. Commando's test my mettle too often.