New Member; new to me '74 Commando Mk??

Status
Not open for further replies.
MexicoMike said:
"It does not leak oil at all,"

No oil leaks? As the old saying goes, "If your [fill in the blank with appropriate old BrittBike name] isn't leaking oil, it's out of oil!" So check the oil! :)

But, of course, before checking it, you need to decide what oil to put in it! Good luck with THAT decision! :) :)

OK, I'm being a bit facetious but all in good fun. Welcome to the site. There's more info here about Nortons than you can possibly imagine. Some of it is actually pretty good.

OOPS...I'm being facetious again, dang it!

SERIOUSLY...the answer to any Norton question can be obtained on this site. I road and raced a '71 Commando back in the day and currently have owned my '73 since '06. It was my only bike between '06 and '14. Virtually everything I have done to it - from total rebuild to the minor odds/ends has been made much easier because of this site. Further, Ironically, parts for our old Nortons are easier to get now than they were when these were actually in production!

Again, Welcome!!!!!
Click to expand...


My 1973 850 Norton Commando does not leak oil. Why does this surprise some old owners? Fix it or upgrade the seals, not so hard to do.
 
Good point. Yes, the static timing just gets you in the ballpark.
To get the timing where you want it by the numbers, (28-30 at 300o RPM, I think) you must verify your timing marks' accuracy (not a simple exercise) and use a strobe.
And a 2BA wrench. And a fan. And a helper. And an accurate tach. And a rubber mat or similar to keep the bike from walking around. And a separate 12V battery for the strobe.

When I put in the Altair, it did still need adjustment from the static-set position.
Pazon will send you resistor plug caps, but I chose to use resistor plugs instead.

Or do it by the seat of your pants, advance until it kicks back, and then retard.
 
Last edited:
998cc said:
rvich, thanks for the note on the layshaft bearings. The current owner of my old '71 Commando wound up having to rebuild the entire transmission/gearbox. Is the issue with the bearings similar to Superblend vs non-Superblend,or are the bearings just not up to the task? Inherent design flaw with the box?

Maybe a new thread here, or should I search the forum for previous discussions of the topic?

Thanks.

998cc
Click to expand...
The original layshaft bearing is/was not up to the job.
I have replaced many for owners and recommend the roller type but a modern ball equivalent works too.
Your model had the cheapest one from Portugal.
So buy a bottle of their best wine , put a heat gun to the box area and freeze that new bearing. Enjoy.
 
Torontonian said:
The original layshaft bearing is/was not up to the job.
I have replaced many for owners and recommend the roller type but a modern ball equivalent works too.
Your model had the cheapest one from Portugal.
So buy a bottle of their best wine , put a heat gun to the box area and freeze that new bearing. Enjoy.
Click to expand...

From what I have read on this forum, the Portugese bearings are undesirable; that's not too encouraging. I have installed bearings and spindles in aluminum cases a number of times, so no worries there. I replaced the main bearings in my Black Shadow in 1979, and during the current rebuild of the engine, I found the outer races for the roller bearings (3) still in place with no movement or damage. The Commando box will come out this winter and will get new (better) bearings and seals. Will probably resort to local wine tho. :D

Regards,
~998cc
 
"...the Portugese bearings are undesirable..."

It's worse than that; they are downright dangerous.
Imagine riding along, noticing that your kickstart lever has dropped down for no good reason, and in the next instant it grabs , swings back up and smashes the back of your leg.
Then upon teardown, you find the box is trashed from the disintegrated bearing and might even have broken the shell.

Fitting those was a major fail, as the kids say.
 
Jag850 said:
My 1973 850 Norton Commando does not leak oil. Why does this surprise some old owners? Fix it or upgrade the seals, not so hard to do.
Click to expand...

They are inherently designed to leak oil because of the orientation of the sealing surfaces. As you said, the leaks can be stopped with some modern solutions - I use Permatex Motoseal - but they came from the factory with oil leaks. Japanese bike did not simply because they figure out that engine/transmissions should not be split in the area that is always submerged in oil! ;)
 
Okay. I have committed to a ride this weekend but will move up the bearing replacement job. Any recommendations for reputable suppliers?
Thanks.
~998cc
 
Last edited:
Has anyone got a procedure for doing lay shaft bearing R/R with tranny in frame?
 
Tornado said:
Has anyone got a procedure for doing lay shaft bearing R/R with tranny in frame?
Click to expand...

I think the Old Britt's site has a gearbox tutorial. the guts all have to come out, of course, and you might as well replace the bushings while yer in there.
I know it can be done, as I watched Steve Payne do the job on my own 850. He heated the case with a heat gun and froze the new bearing prior to install.
Examine carefully the small area of the inner case, between the bearings, as it's prone to cracking...
 
Gut the gears. Mainshaft stays in place. Heat gun the layshaft bearing aluminum box area, a torch won't work because it will flame out from lack of oxygen. Pull hot bearing out ,wear leather gloves. Tap frozen new bearing in. Re-assemble.
 
If the layshaft is a tight fit in the bearing (as it often is) then leave it in position. When the case is hot enough the layshaft should pull out with the bearing still attached and it can then be removed from the shaft.
 
Andover Norton only stock a roller bearing. I seem to remember this is what Mick Hemmings supplied before AN took over his stock. You then need to shim the layshaft for endfloat ( not difficult) and there is instruction on this on the net. (Oldbritts??)
 
The OldBritts write up is for full tranny stripe and rebuild and has it out of frame.
https://www.oldbritts.com/gearbox_d.html

Is it possible to do layshaft with tranny still in frame? Trying to avoid removing primary inner/outer and disturbing the triple chain tension etc.
 
Last edited:
Tornado said:
The OldBritts write up is for full tranny stripe and rebuild and has it out of frame.
https://www.oldbritts.com/gearbox_d.html

Is it possible to do layshaft with tranny still in frame? Trying to avoid removing primary inner/outer and disturbing the triple chain tension etc.
Click to expand...
Yes you can , I've done it twice for people. We already told you how if you read a few entries back on this thread. Get a good heat gun , leather gloves , a freezer or ice pack nearby for the bearing. When the magic moment comes work fast to get the frozen bearing into the hot case. Don't worry too much about a hairline crack between the mainshaft -layshaft bearing bores unless you are a racer.
 
Last edited:
Thanks all. Good stuff.
The plan is:
1. new Amal Premiers 932's.
2. Gearbox/transmission bearing kit.
Looking to do it all Thanksgiving week. However, getting the gear shift/Kickstart cover machined for seals is appealing. Anyone know of a reputable shop near Sacramento, Ca.??

Looking for a nice, new, comfortable seat. The original has been recovered but is like sitting astride a piece of 2X8 lumber!

Did 130 miles last Saturday on back roads in the Sierra Nevada Mountains.
Did 50 miles running errands today.
The weather is good here--gotta ride while the riding is good.

Best regards,

~998cc
 
Re seat...have heard original can be a solid lump...likely from 40+ years of fossilization. I bought a repro seat from Walridge (Xmas sale item for $230 cdn) to replace the stock fugly banana seat that came with my HiRider. The repro came in a box marks Staffordshire England. It is well made and the ride is very comfortable...more so than my 2013 Bonneville single seat T100.

Of course you could also explore replacing your seats foam core and even the skin.
Kits are available for both. Or take it to a local place to get a custom job.
 
Status
Not open for further replies.
Back
Top