Hi guys,
Struggling with my gearbox and my limited knowledge / abilities / tools is making me wary of touching the bike any further...
My gearbox is not working correctly and I'm getting more and more disheartened by it :-( Is there ANY mechanically minded and knowledgeable chappies out here that are based in Central Scotland and willing to help me out?
Here's hopeful
Best wishes
Ian

email (option): fozzie001@hotmail.com

Hi Ian.

I can't drop around as I'm on the other side of the globe but the collective here might be able to help if you can describe the problem that you're having with the gearbox.

Ian, just a thought that if there is no-one on this site close to you, joining the BSAOC would likely allow you to tap into local help as I am sure rhere will be members close to you with M20 type knowledge. A lot of us Matchless types belong to AMOC and it has always been a help for me.

Thanks for the suggestions guys.

Basically, the problem seems to be two fold...

Setting off in first is fine, clutch is lovely etc.
Goes smootly into second
When going into third, she goes into a false neutral
When again trying to go into 3rd from the false neutral, she goes into fourth.
When shifting back to try to engage third, she drops into second!
After a bit of jiggling about, third gear is eventually located.
Then on into fourth.
Once in fourth, open the throttle and she slips the gear, almost as if I'm riding the clutch :-/

The only clutch adjuster I can see is the thumbscrew adjuster on the cable end at the top of the clutch arm at the gearbox, there is no screw adjuster at the base of the clutch arm / shaft.

I had problems earlier in the year with the clutch, which I stripped down, cleaned, re-sealed and re assembled & it "seems" to work fine now

Happy to stick bike on trailer and take somewhere that's not a million miles away for help.

Any ideas guys?

email (option): fozzie001@hotmail.com

I'm no expert but I rebuilt my transmision and engine by following this site and my bike is running great. Its possible the 3rd and forth gear selector fork track and pin is worn? Or there is a problem with the pawl and ratchet being worn or ajustment of the control rod.

My m20 was my first endeavor into rebuilding a motorcycle of any kind. Just search the forum for gearbox and read everything. I am certain you will have to pull the gearbox apart to discover the problem.

email (option): xeon25@hotmail.com

Ian a lot of us will have experienced that false neutral between 2nd and 3rd. It catches me out every now and then if I try to hurry a gear change. It usually requires a firm press the pedal to feel it click in before engaging the clutch. Although your problem could still be inside the box, but better to check what you can before opening the box.

But reading your post makes me wonder if you actually have a workshop manual?

The clutch adjust is quite important to get right by following the instructions properly with a combination of cable and adjusting screw. But you say you haven't got the screw. There's something wrong there!!

Also inside the outer 'kickstart' cover ( which is fiddly to remove/replace) is an adjustable rod which is quite sensitive to adjustment.

As mentioned before, there is info in the tech section or I can scan pages for you by email. Ron

email (option): ronpier@talk21.com

Yes, the Technical Section...
All the problems I encountered with that d*****d gearbox are described there

Hi Ron,
Thanks for the nods towards a manual - indeed, I do not have such a beast in my colelction :-(

I will go back out to the bike and have a poke around, but, last time I looked, I am certain the screw at the bottom of the clutch adjustment lever was absent - as in, no hole, no threads, as if it was never there in the first place, but, the lever looks like it's original and functions more or less as it should...

The more I look at the bike, the more puzzled I become! :-/

email (option): fozzie001@hotmail.com