pre deal questions 73 commando750

Hello, My background in MCs is with 70s Honda cbs. My daily rider is a 74 cb750 and I'm in the process of restoring a 73 cb350 four. I have an oppurtunity to trade the cb350 once finished for a 73 Norton Commando with front disc brake. The commando is non running with the motor in pieces but it's all from a very reliable source. Original sparkle blue paint and also comes with a extra "combat" head.

I've seen a few Commandos fully restored at local vintage MC shows and have always drooled over them but really know nothing about british bikes let alone two cylinder motors. I've been reading some posts and doing some searches about the commando and combat head, so far what I've read is a little disconcerting though it doesn't seem to have stopped all on this board and others from owning a commando.

I'll have plenty of questions when I actually start restoring but I would like to get some answers about a few things prior so that I might get some parts ordered before assembly. First of all the combat head has me concerned if I'll have to get new bearings as I've read superblend bearings are needed to run the combat head. I've also read about the problem with the oil sumping down into the case and possibly burning up the top end. Not really excited about modifying the case to fix this. Would my year have these issues.

I'm hoping to get the facts straight about these issues and would appreciate any info of other major problems before I get started.

Pre-Deal,
here is my thoughts as if Iwas going into this trade.
Ask where the combat head came from. Is the motor already detuned w/ another head?
Commndo's don't routinely come w/ an extra head.
If life is good and it was detuned possibly the bottom end was addressed?
You said a credible source which is goodnews for you as thisisall you have w/o documentation.
Ask for any parts receipts. I got a few w/ my 72 combat and they were from 1979.
It will let you know whats been replaced, possibly.
I've put just over 1,000 miles on my recent restoration.
I had 8,000 miles on the orig speedo and took it at face value.
I purchased it privtely. I wouldnot believe a damm thing from an ebay seller,
expect the worse and pray for a decent machine to arrive.
If you are buying from a local possibly the info you get will be close to what has been done.
By summer of 1973 the switched to the 850. You probably have the newer bearings.
I drive mine around between 4,000-5,000 rpms and she is holding together.
You are not going to ride it twice and have it explode hopefully.
It will be an experience comming from the land of the rising sun machines.
The lookI get w/my yellow comabt is priceless.
If a majority of the orig parts are there it can be a rewarding experience.
Just curious what are you spending for this dissassembled?
You can get a runner for $3500-4500.00
If your trade is worth much less it could be a decent deal.
You'll will definitely go to theNorton first on every nice riding day after she's done.
Ask a man who knows I have a $16,000 electra glide parked next to my Norton.
Guess which one is more fun ?
Ask lots of questions we have your back 8)

The situation with Superblend bearings and the Combat head are unrelated unless the bike was originally a Combat within a particular range of serial numbers that had unacceptable OEM main bearings.

The oil starvation is another issue that would have to be addressed if it is withing that certain range of production with the lip at the rear of the sump.

Oil pump should be refurbished to minimize drain-back no matter what year model. This won't burn up the top end, it will just slug oil out of every possible joint on the engine, and raise a cloud of oil smoke like you've never seen.

Welcome to the forum, and don't be afraid of Commando ownership.

You don't need to modify the case to stop wet sumping. I installed a $15 on/off simple valve in the oil line and turn
the oil flow off after a ride.

There is a very good chance that the main bearings were replaced with superblends years ago, as this is a very well known
issue.

Since you are new to commandos, yes they are great to look at, but seriously be prepared to put out lots and lots of
money getting things "right", it WILL be one thing after another, lots of learning, lots of frustration.

In my humble opinion, the commando is one of the highest maintainance motorcycles every produced.
Be prepared for the necessity of learning to do just about everything possible by yourself.
You will get the best possible advice here if you choose to go down this road.

The case modification relates to oil STARVATION issues, not "wet-sumping". Research the criticality of this issue on the Old Britts and other websites.

Manually operated "on off" oil line valves are a serious danger if you should ever forget to turn the flow on before a ride. Once is all it takes. Some in-line check valves are reputed to be just as dangerous when they fail to operate as advertised.

Grand Paul,
criticality ?
My wife says I make up words in the kings English too.
If this was Scrabble I'd challenge it :lol:
Just kiddin I liked it!
Everyone only hears about the negatives.
Do people even remember Norton won allot of races
They must have been doin something right back then :shock:
Marshal

You don't need to modify the case to stop wet sumping. I installed a $15 on/off simple valve in the oil line and turn
the oil flow off after a ride.

Click to expand...

That's inviting disaster, unless your memory is 100%. For near that price you can get a spring loaded inline check valve. Even that is a bit dodgy. I would never put anything between the oil tank and the pump except a hose. The best fix is to install the MK III spring and ball on the pump output.

Grandpa, for your information there are a number of ways to insure that a simple valve in the oil line works just fine.
Some people make an electronic, others a simple steel fishing leader, running from the valve to the ignition switch
of commandos up to seventy five to ensure they cannot be started without the valve in the flow position.
I have no interest in your suggestion to buy a spring loaded device. That can fail, my set up has no internal spring to fail

Myself, I do not do either. I have had this setup for fifteen years and have never forgotten to turn the valve on.
It is as natural to me as turning the gas petcock on.

If the motor is in pieces, this might be the perfect opportunity to do those modifications!

If you decide not to take this trade, perhaps you will let the rest of us know where to find this bike! :wink: