swooshdave wrote:

comnoz wrote:To help first gear you need to install a shim between the inner case and the kicker shaft to move the kicker shaft and first gear to the left . That gives deeper engagement with the sliding gear which is being located by the shift fork.
Jim

That is the way Fred shims it.

That is the correct way to shim it. That needs to be done with a ball or roller bearing . The choice of the bearing will not affect the need for shimming here. Jim

No they didn't shim them at the factory. And many get along fine with no shim there. But if your bike wants to come out of first gear when you are driving away from a stop that will usually cure it. jim

God, my friggin head is swimming. I've had my first commando for over a decade and been on several forums and email lists for nortons and I have never picked up on this bearing failure as a common issue after such a short period of miles. I have at least 20K miles on the bike since I bought it and I have no idea if the tranny was rebuilt before I bought it. So potentially this trnny has 30+ thousand miles on it and no real issues other than occasionally not wanting to shift properly. I am definitely going to have to rethink my trip to barber and how I get there.

britbike220 wrote: ... I am definitely going to have to rethink my trip to barber and how I get there.

Just go and have a good time. God knows that you could have a flat, the rear axle could snap, the ground wire could break off your Boyer, etc. There are a thousand ways for the bike to break down. If you thought about all of them you would never get out of the yard.

With 30,000 miles on the bike the layshaft bearing probabaly has been changed. If you are really worried, change the bearing. If you worked at it steady you could have it done in half a day (the second time you did it). Plan on a whole day.

Greg

Welcome to the motor sports hobby world, especially obsolete British and in particular the Commando. Its a hobby that tests your mettle as a man in any way measured. I've been so many times up 4-5 am to repair/replace some item working fine right up till night leaving on a trip with friends. Barbers is a month away, plenty of time to suck out and re store a gear box if ya the cash on hand to get started this week. Thanks goodness it revealed its issue before far far away. I thank my lucky starts Trixie's rod bolt let got on my work commute and not in another state 140 miles away the night prior. That was after the 1st deer did Trix and me in, so did 80-85 where possible to feel more secure.

Just know took me about a decade to get familiar with Combats, I expect another dozen years picking up more shop gems like this kicker shim I've not had to do, so far.

If you have not spent a season or 3 reading everything in Cap. Norton's site, you are missing out on whole bunch of history and people and solutions gone down long before our time with a Commando challenger. Creeping up on 4 decades past soon.

Its worth while to groove the sleeve gear bushes and stack 3 inline so they don't drift together leaving shaft less supported.

Is there a link to the bearing replacement process. Just curious if you have to pull the primary and clutch off, or can you get the layshaft out with the mainshaft in there?

Hopefully you don't have to actually pull the tranny case out of the cradle.

lrutt wrote:Is there a link to the bearing replacement process. Just curious if you have to pull the primary and clutch off, or can you get the layshaft out with the mainshaft in there?

Hopefully you don't have to actually pull the tranny case out of the cradle.

There is an excellent article on gearbox rebuilding by Fred Eaton of Old Britts. Has great photos that have helped me a lot.

lrutt,
Les(LAB) on the forum has some excellent pics he helped me a few months back w/ same question.
Search using "layshaft".
But yes you can leave the primary side alone, trans in place in bike and remove layshaft w/ main undisturbed.
I know this will stir some contraversay as many will tell you while your are in there replace all bearing,bushes,seals
kick pawl etc...
I'm only replacing the layshaft bearing because of history of failing.
I'm also replacing the kicker pawl due to a possible fractured pawl.
Kicker slips a tooth here and there now and then.
If my gears are not chipped and the rest of the non problem bearings are sound I'm going to button it up and
continue my riding experience.
It has just shy of 10,000 miles on it, original miles.
I'm going at it w/ a heat gun 1st before I put a flame on the aluminum housing.
I'm doing a replacement ball bearing but again I don't plan on racing the death out of her.
I purchased an SKF 6203 c-3 for around $5.00. That's what is in there so I'm replacing it with modern same.
Ask away as you go we all did along the way.
Marshal

Yes, it can be done.

IMHO, you won't save time or labor that way. What you save in terms of primary removal you'll add back in terms of unwieldiness of dealing with the box and mainshaft in situ. BUT no reason not to try - you can always walk around to the other side of the bike and remove the primary at any stage.

Best of luck. THIS IS NOT DIFFICULT. Tedious, yes. Difficult, no. Rewarding, yes.

I like the fact it is still on the bike cause I can get my son to step on the rear brake when I break loose the main shaft nut.
Marshal

It's all do-able either way. Off the bike, a vise was my best friend. Propane torch was close behind.

I just did mine for peace of mind before a trip. Did it in the bike and I had never really worked on a trans before. Follow the Old Britts info, it's not a brain tease at all. Used a air wrench for the main nut and small torch & lazor thermometer to heat the case to pull out the old bearing. Will need bearing pulled. Even a Harbor Freight one. PS. Marshelnorton, you can NOT use a regular $5.00 6203 bearing. That is the one that fails. It must have a polymide cage and will be quite a bit more $$$. 6203 TB C3 will work. Search all the Layshaft bearing posts. It can be a one or two day job.

Well now you've got me worried. My MK-III just passed 15k. Shifts nice and smooth, no movement on the kickstart, no evidence of metal when the gear oil is drained. I don't know if the PO maybe changed the bearing??? Is this problem absolutely gonna happen? Or were some gearboxes assembled with different bearings? Is there any way to tell?
I could make this part of my winter projects list, but there are a lot of potential miles between now and then. Just how concerned should I be? I'm liable to run into something while I'm staring down at the kickstart.......