Gear box problems 1958 super rocket

[tony]

Went for a ride this morning and tried to change down to second but it wouldn't go.  It did eventually so I thought I'll adjust the cam spring to what the manual said so I can see two threads showing and now I'm unable to get 3rd and 4th gear.  But 1st and neutral seem to be ok.  The spring is original spring, if I change it to a new one do you think that would solve the problem?  Can't seem to adjust the old one without loosing gears. If I do the lock nut up tight showing the two threads the gear lever jams sometimes. I pulled the complete mechanism out, could that cause a problem?
Thanks, Tony

[bsa-bill]

 Others may have had similar problems with the spring plunger dodah (ok I forget it's name) but I wonder if slight out of adjustment would cause all this.
If the problem might be elsewhere Tony have you checked the spring on the gear change lever pawl inside the outer cover

[muskrat]

Gear control cam plate spring & plunger Bill. Most people call it the detent spring & plunger.
Cheers
Tony, was it all good before your fiddle? " I pulled the complete mechanism out, could that cause a problem?"

[Topdad]

Just to check why don't you select neutral and pull the assembly out ,I think it's called the indent pin or something like that . My thoughts would be that if you've not had any change in selection up to that point ie no increase in neutrals it's the easyest place to start . It catches all the crap so a agood clean up and readjust may sort .The spring may obviously be worn or poss even broken . Start there and then move onto Bills idea if no improvement .Hope you sort it regards BobH

[tony]

Cheers for your ideas.  I've been tinkering with it today and what I found is that when I do the lock nut up tight it distaughts the tube which the spring and the plunger goes into and it jams. Then I can't get all the gears.  But by slightly loosening it, it frees and I hear it click up, then I can get all gears.  Ordered a new plunger assembly today.  Will let you know how I get on when I fit it.  It was kind of working fine before I tinkered with it, just jumping out of gears.  The spring isn't broken, just old. If this doesn't work I'll have to pull the front cover off and check the gear change lever.
Thanks, Tony.

[tony]

I got my part today and fitted it.  It worked, as I can select gears without the gear lever jamming.  I could select 1st and 2nd but 3rd and 4th half the time I can't find them, other times I can find all the gears.  I've not ridden it yet but tested by hand.  Would this be down to the selecter spring? But its had a new one put on a few years ago.  When this problem occurred I thought it was the cam plunger but its not jamming up anymore but I just still cant select all gears.  When I had the bike running in the garage it was clonking in gears half the time.  I'll take it for a run tomorrow and see how it goes.  Is there anyone locally to Leicester that can help??
Cheers, Tony.

[duTch]

   G'day Tony, I'm assuming that you're rolling the rear wheel as you do this ?

        Cheers, duTch

[tony]

Cheers DuTch,
Yes I am,  but when I turn it by hand the same thing happens.  When I took it out for a run 1st and 2nd gears seem fine but 3rd and 4th half the time aren't there when I try to change down to them.  The adjusted spring seems to be working fine as its new.
Cheers, Tony

[muskrat]

G'day Tony. Are you sure the indexing of the selector plate and quadrant are correct? If OK it could be a selector fork / camplate problem or even the selector fork shaft has worked it's way out a bit (loose or missing grub screw).
Cheers

[Stephen Foster]

Jim ,

With the gearbox in the frame ..what is the correct "drill" for adjusting the cam plate plunger ?

Is it just trial & error or is there a method ?

Steve ..

[muskrat]

 Mine are a few threads further out than the recommended two, for fast light changes. Only if all the dogs and their "kennels" are in good nik.
If I were doing a box I didn't have apart to inspect, I would start at the recommended two threads showing and test it. If all ok I might back it out a thread or two but at the slightest sign of trouble it would be back in.
Cheers

[tony]

Thanks for all your advice.  Got to the bottom of it! The reason I couldn't select gears was because the two dots were not in line in neutral.  The first photo is how it was in neutral.  So I pulled the case off slightly and set it to neutral, I couldn't pull the case all the way off?? But managed to pull it out about quarter inch and freed the quadrant to line the dots up in neutral.  I need to find out how to pull the whole inner case off though for future?  I did it years ago but must have set it wrong.  The plunger adjuster was not working properly so got a new one which doesn't lock up now.  Been out for a ride today, works lovely.  Come winter I'll take the gear box off and replace the bushes on the kicker start and the gear lever as they seem to be a bit on the loose side.  Also my kicker jams sometimes so probably get a new kick start spindle.  That should solve that problem.
Thanks,
Tony

[muskrat]

 Yep, that'll do it. Good to hear it's sorted and an easy fix.
The inner cover should come off in pic 2 after that last screw is removed. Did you remove the long studs or have they been replaced with bolts? Might be a bit tight on the shafts.
Re the kickstart jam, "they all do that sir". If it only does it once in ten/twenty kicks it's OK. If it sticks every third or forth kick look at the pinion bush, kickstart spindle bush and kickstart lever spindle bush. Lastly the quadrant and pinion teeth. Caution as there are two types of tooth form and must be matched to work.
Cheers

[Topdad]

Hi Tony, very annoying ,had the same thing when I rebuilt my box with enormous help from guys here ,turned out the dot's on mine ,when lined the cogs were in neutral were out  and I had the same probs as you and sorted it the same way as yours ,I didn't think it could be that has you said the problem only just started on a ride out .This proves the saying "never assume as it will make an ass of you  " Glad you've got it sorted. This posses the question of how they get out of cinque when securely fixed between the cases inside the box?? Over to Musky and the experts to answer.Regards BobH

[bsa-bill]

In my Rocket (type) box the dots can't be lined up, got to be a bit out one way or the other, of course when you put it together you discover it's "the other", probably just an add up of the tolerances in there