1972 Norton Combat Commando 750 trade-up & refurb for eventual sale


Author, "Old Bikes"
I'm going to back-fill this thread with a project I started almost a month ago. It's about a somewhat limited edition Britbike that:

1. Will do the ton without a lot of fuss (so it's on topic for the forum)


2. Involved some basic, and some advanced "horse-trading" (which just makes it a little more interesting)

Turn the calendar back to late 2007. I caught wind of a package deal, a Triumph trike/chopper project, and some of the late "Oil-In-Frame" Bonneville parts that were left from the donor bike that the engine came from, cheap (relatively speaking, of course). Biggest problem was that it was in the Philadelphia area, almost 2,000 miles away. I worked the deal, made a second deal with a friend of a friend who lived close by, arranged for a custom crating company to build a crate to spec and deliver it to where the stuff was, and made a call to have a shipper pick it up and bring it to me. It didn't take too long for the previous "cheap" deal to turn into a "not-so-cheap" deal.


When I opened the crate, I had my trusty helper/gardener assist with the un-crating that involved an unbelievable number of giant "bread bag ties" and holes drilled all over the bottom and sides of the crate. We had prepared the day before by scrounging all around the shop and stacking up all the parts I thought I could use on it. Here's what we came up with:


I had that seat sitting on a shelf for a couple of years, and the keg was one of two that a local distributor gave me when my wyfe and I used to put on an annual charity fundraiser motorcycle show event (2000 - 2008, those were some great years).

The bike got rolled from the back of my shop to the front slab at least 3 or 4 times, with the most recent stint of about a year and a half on the slab up front...
Fairly quickly, I build up the OIF into a reasonably complete rolling project, using another engine & bodywork I had laying around (turned out the engine in the trike was not matching numbers to the frame that came with the deal); sold it immediately on e-bay and shipped it to Canada after chopping down the crate that the trike came in. I sold the leftover forks and the few other spare bits off, I may have actually tossed out that Invader wheel (mistake, I know).

So, turn the calendar pages up to about 2 years ago.

I tried to sell the trike project on e-bay and got no bites. Then I tried to sell just the trike frame, and just the engine separately; also no bites.

Now, turn the calendar back to last month. I happened to see a post on a Facebook British Bike Mechanics forum, a guy had a scruffy, incomplete, but rolling, Norton. He didn't know what year or model it was, but shared the serial number which told me it was a '72 Commando 750.


He was taking offers and nobody was biting (it looked real rough, and it was known that the engine was frozen), so I offered him the trike; he liked that idea and we made a plan to meet a few weeks later when I would already be traveling up I-35 to take my son his boat (left with me while he deployed to Germany, Army Med-Evac Blackhawk pilot).

We met up, made the trade, and I got to tearing it apart pretty quick. So here's the blow by blow...
First, I removed the head steady, and it's got the "C" stamp (looks legit to me); so it's definitely a Combat engine (I already assumed that from the fin spacing between the head & cylinders). There is no "RH#" stamping, though.


So, looks like my "investment" in the trike long ago, finally paid off. I've still got several spare parts that will help make it more complete, (it came with a good primary cover, not pictured) and it's a simple matter to pop the fork caps back on to make it look like a bike again...

Already got a few parts installed from what I had on the shelves, looks a bit better...

From 7/21

Handlebar swap done, looks like a normal bike again.


Primary cover is dull but decent.


Transmission is uncharacteristically clean, no milky mess, no rust. That's big.


Now, let's see about that stuck piston...

Left intake was relatively clean.


Left exhaust somewhat junky.


Right intake surprisingly clean.


Skanked-out right exhaust port where the moisture got in.


Head is inverted, so right cylinder is on the left. THIS is where the problem was.


Right cylinder is badly stuck, left side not too bad (that's WD-40 in there).


The head will clean up real easily.


Right cylinder is basically trash.


Cam lobes look fair, no severe wear, just the typical uneven factory finish.


These lobes are in good shape. Cam followers aren't flat spotted at all, so that's a big plus.


Right piston was well and truly stuck. Also evidence of severe blow-by.


Left piston is not bad at all, it was on the compression stroke with both valves closed, so no moisture ingress damage. Still has severe blow-by damage.


These are NOT the dreaded "pop top" sliced pistons, thankfully.
7/21 (it was a long day)

There were no cush rubbers in the rear hub. Clack, clack, clunk!


Rear fender & wheel removed (temporarily on the wheel)

7/21 (still going)

Stripped off the wiring harness, oil filter, cooler & hoses.


All levers, cables, and front brake removed.


Clutch was pretty heavily contaminated with thick tranny lube.


Nice surprise - $hurFlex lightweight composite clutch friction plate$!


It's always nice to see the inside plate still securely pinned in place.


"Flip Side"

7/21 (for the last time)

Primary didn't put up too much of a fight, I did have to employ the puller to get the engine sprocket free.


That's as far as it's going, bare rolling chassis to be scrubbed and touchup painted with gloss black Rust-O-Leum rattle cans.


End of another long day...
I think I'll post each day I worked on it one day at a time, just for the heck of it...
A bit more interesting info- The guy that got the trike traded it for a flatbed double-axle trailer and some powdercoat work. He then traded the trailer for a Harley evo big twin engine with a 5-speed transmission. I'm not into HDs, and don't know the value, but I think he did pretty well starting with a rusty old Norton he paid FIFTY BUCKS for!

Scruffy, empty rolling chassis


Clean and touchup-painted rolling chassis


Scroungy bottom end before clean-up


Clean bottom end (heavily flushed inside as well)


Tranny before clean-up


Clean tranny (flushed inside as well)


Filthy inner primary case half


Inner primary cleaned up, not yet detailed.


Kinda rare situation, chaincase is completely intact, no cracks at the 3 crankcase bolt holes or center boss, and the chain fling lip is completely intact.

Tranny back in it's cradle, re-assembly has begun.


Lower end bolted in with original isolastics (in fair shape)


Sprocket is SLIGHTLY hooked, but not terrible.


New primary inner case gasket in place, ready to assemble primary system.


Nice clean clutch plates; friction plates are $ureflex, steel plates are cleaned and lightly scuffed, pressure plate cleaned.


Step 1 in proper assembly of primary is to gently snug the 3 inner bolts in place first...


Step 2: measure gap between case backside and the shoulder of the stand-off stud.


Step 3: Locate proper washers. One thick washer, one thin; just right.


Step 4: Remove 3 inner bolts, slip in the proper washers, then tighten everything in place properly. Done.


Primary system all shimmed in place, clutch plates & diaphragm spring installed, alternator cleaned & installed. Ready to nip it all up.


I found 2 of the 3 inspection caps, and a proper sleeve nut for the center stud. Just need the 3rd cap & main cover o-ring.


Tires are shot, as seen in this close-up (although they are still holding air). New filter has been knocking around my shelves for over a year, finally got a place to put it.


Here and there, I always end up using my serviceable spares from lot purchases over the years. Almost like it's free. So far, well over a couple hundred dollars of old dusty parts that are now cleaned up and soon to be back on the road.

Battery tray all cleaned up and spray painted.


Horn was HEAVILY caked with dirt and grime; cleaned up and painted. Mud dauber nest removed from inside, too...


Oil tank solvent washed, then pressure washed, then spray painted.


Man, this 100-plus-degree heat is beating me up. Even with my 36" Port-A-Cool parked 4' from my work are, and a 24" Shop Cool fan posted at my parts wash sink, I've been drenched in sweat for almost 6 hours. I tend to lose between 10 and 15 pounds every summer.
Top Bottom