New(ish) owner intro

Just joined a few days ago from NJ, USA. I won a cafe'd '72 Commando on a whim bid at Iconic Auctions back in January. It was previously a Cafe Racer project bike. As a project bike, it had a nice CBR front end and custom shocks. Now it has a stock front end and (I think) CB1000 shocks.

By the spec sheet, it's pretty nice. Alton starter being the best bit, but also a recent engine rebuild, a Brembo caliper conversion, nice rearsets, nice pipes, etc. The assembly is a complete trainwreck but I was expecting it to be. Maybe not quite as bad as it is but I need something to do, right?

In truth, I don't know much about Nortons but there are NINE of them in the shop I share with a couple friends. Both agree - solid hard parts, indifferent assembly, some really dumb sh*t.

It runs quite well but I fouled the plugs and (foolishly) cranked the hell out of it until it now sounds like I've messed up the sprag clutch. Because I am dumb and didn't realize I should be worried about that. It leaks a shocking amount of oil from the primary cover so I need to get in there anyway. I just finished a couple other projects (helpful hint: don't by new bikes from Piaggio Group) and it's time to put the Commando on the lift.

Hmmm..I'm not seeing a way to upload pics, so here's a link to the Iconic auction: https://iconicmotorbikeauctions.com/auction/1974-norton-commando-850-2/ and a pic from it.

PM sent

I can't reply yet. Middletown.

Looks like its got some good upgrades too it, make sure it hasn't wet sumped as starting it with a full crank case of oil could blow out the left side crank seal and fill up the primary case, run ATF in the primary case with no more than 7 floz of oil for the chain lube, its had a bit of money spent on it so get to know your Norton and learn the little faults they can have.
Good buy and enjoy.

Ashley

To post pics directly, you need to be VIP member.

The commando does tend to wetsump if not run in weeks/months. Running an electric leg or starting up with meat leg when moderately wet sumped puts high loads on the starter and can also lead to crank oil seal blow out into primary side...making primary fill with oil and leaking out at the gb sprocket opening.

So if sat more than a few days, best to check/drain the sump prior to starting until you know how severe your engine does this. Afterva good 20 min run, check oil in tank level, then compare it at next pre start up day...any significant drop, do not top up until you drain sump first...otherwise risk overflowing tank out breather as excess sump oil is pumped back.

I have an Alton too on my 73 850. You say you may have messed the sprag. It may be that you have instead sheared the internal plastic dowels that protect the Alton from kickback.

The Alton internal plastic dowels protect the starter motor from kickbacks as they can destroy the motor. The idea is that they shear first and protect the starter motor. You then pull apart and replace them.

Very important is to have an electronic ignition that, under 500 rpm, has ATDC timing. The TriSpark has this.
If you have ATDC spark under 500 rpm, you will not shear the plastic dowels.

If you do pull it apart and inspect, do keep into touch on forum or by private message.

Dennis

Thanks for all the tips. Regarding the wetsump issue, I forgot to mention that the bike has an NYC Norton anti-sumping valve. My friends had warned me as well (one had been a victim, in fact) but I gather that the NYC Norton part protects me here.

I'm hoping the shear pins are my starter problem but I won't know until I poke my head in there. I forget what ignition it has.

I'll be sure to post pics as I dig in. While the bones are there, there's a LOT wrong with the bike. I would have been embarrassed to sell it as it is but here we are. I was actually enthusiastic about subscribing to Cafe Racer magazine until I started going over the bike. Now the idea of giving them money pisses me off.

The

mfennell said:

I forgot to mention that the bike has an NYC Norton anti-sumping valve. My friends had warned me as well (one had been a victim, in fact) but I gather that the NYC Norton part protects me here.

Click to expand...

Do you mean this?



If so, that is the best crankcase breather but not an anti-sumping valve.

I don't think Kenny makes an anti-sump valve and I don't see one in the pic.

They usually look like this


Or

gortnipper said:

The

Do you mean this?

If so, that is the best crankcase breather but not an anti-sumping valve.

I don't think Kenny makes an anti-sump valve and I don't see one in the pic.

Click to expand...

@gortnipper, you are correct! It was in the ad as an 'anti-sump valve' and I just assumed that's what it was. Googling let me back to a post on this site suggesting it flows well enough to avoid blowing out the seal.

It does help with the pressure, and while I also have one on my bike I still drain the.sump if the bike sits idle for a couple weeks.

mfennell said:

@gortnipper, you are correct! It was in the ad as an 'anti-sump valve' and I just assumed that's what it was. Googling let me back to a post on this site suggesting it flows well enough to avoid blowing out the seal.

Thread 'Comstock / NYC sump breather test'

Aug 4, 2022

Ok kids, yesterday I performed a very scientific test.

Actually, by accident…

I’m not sure when I last ran the Commando, but it definitely hasn’t run this year, so it’s probably close to a year since it ran.

I did a lot of things to it, stripped and rebuilt the forks, new battery with different wiring arrangement, new front tyre, etc, etc. But I knew that all oils etc had been refreshed prior, so oil wasn’t on my mind.

The Commando is the only bike in my shed that wet sumps…

So… I forgot all about the wet sumping didn’t I !

When it was finished, I pressed the button on the cNw...

• Fast Eddie
• Replies: 30
• Forum: Norton Commando Forum

• 

Click to expand...

Yes it helps evacuate excess oil in the sump very well. And it is an excellent engine breather, I run one in two bikes currently.

Gortnippers point though is that it does not actually prevent oil passing through the pump and into the sump when stood.

It just shows the ignorance of the people who think they can just step in and build a one off Norton or any Brit Bike for that matter with out proper guidance. They are diifferent. Their biggest appeal is also their Achilles Heal, the 360 degree crank.
Both pistons rising and falling at the same time. The upstroke draws in air in the crank case, the downstroke blows it our somewhere.
Sometimes right out the joints. Combine that with a case full of oil on initial start up and you can imagine the mess.
Kenny's breather has a one way reed in it. With a sumped case, slow and deliberat kicks will clear the sump by pushing the oil out and not letting it back in. Usually two or three slow kicks will clear the sump. You can actually feel it free up.
If the sump is completely full, the E'start is turning it rapidly and possibly causing a Hydraulic lock which shears those pins.
Depending on how long it sat it could have sumped into the primary, which when run will blow it out throught the trans main shaft felt seal, making a big mess.
If is wet sumping that bad, an incorrect seal or no seal could have been installed at the pump to outer cover.
The pump also needs that paper gasket between it and the case.

Would suggest to verify empyty sump before starting after sitting for awhile.
If you're really serious about getting it right, you are at the right place. Albeit, may take some thick skin from time to time.

Admittedly, watching the video, appears to start and run fine..

mfennell said:

Thanks for all the tips. Regarding the wetsump issue, I forgot to mention that the bike has an NYC Norton anti-sumping valve. My friends had warned me as well (one had been a victim, in fact) but I gather that the NYC Norton part protects me here.

I'm hoping the shear pins are my starter problem but I won't know until I poke my head in there. I forget what ignition it has.

I'll be sure to post pics as I dig in. While the bones are there, there's a LOT wrong with the bike. I would have been embarrassed to sell it as it is but here we are. I was actually enthusiastic about subscribing to Cafe Racer magazine until I started going over the bike. Now the idea of giving them money pisses me off.

Click to expand...

Even with the sump reed valve device, you need to be aware to not top up tank prior to a ride if its been sitting a while...too much oil in the sump and a topped up tank makes for an over fill/overflow situation out the tank breather.

I want to add that bike looks nice and worthwhile to fettle with and get right.
There is also a lot of niceness going on there.
I also think it deserves dual carbs with stacks. But, that's just me...