S29 Sloper 3 Speed Gearbox problems

[BEVANC]

Hi folks,
Had an enjoyable ride out on a lovely spring day here. Unfortunately, when I came to head back home, the bike jammed in 1st gear.  The clutch disengages correctly and I can shift the lever between 1st and neutral positions, but it remains in 1st. Can't move the lever up beyond the neutral position.
Had an ignominious ride most of the way home on a bike trailer 

Obviously I need to strip the box, but has anyone got any suggestions as to what might be the cause ?  I presume a jammed selector fork is a possibility.

Cheers,
Bevan

[Paul.W]

there are now two of us needing help with gearboxes......

Have you looked inside? I've not had mine completely apart, but I have found that if you remove the top plate (4 small screws) you can see the selectors operating as you move the lever.  You might be able to see whats going on.  The other thing that is easy to do in situ is remove the side cover and expose the gearchange mechanism. I'd do that first to see if there is anything amiss with the quadrant that provides the gear detents and rotates the selector shaft.

I'm sure much more knowledgeable people that me will be along shortly.

[BEVANC]

Hi Paul, looks like my selectors are jammed. However, I have another more worrying problem - I decided to take the clutch off, but have found that the left hand threaded bearing retaining cup has been subject to some heavy hand with a punch and is jammed tight on the mainshaft threads. I don't want to cause further damage, but am unsure how to proceed.

[Paul.W]

Yours is slightly different, I have a rather manky looking circlip that I haven't tried removing yet (see photo)

Looking at your photo I wonder if there wasn't a special tool, is there a corresponding slot on the other side that can't be seen?  if I were in your position I'd take it to a mate who has a decent workshop with an air hammer.  Lots of small blows aimed at that slot that's visible might jar it loose without doing any more damage.

I expect someone will be along soon to tell you how it should be done.  When you get it all apart you can tell me how to dismantle the kickstart mechanism.  Aren't old bikes fun!  I was planning to use mine tomorrow, but it looks like I'll be using the trusty old Velocette 

[BEVANC]

Yes, there is a matching slot on the other side. I was musing on whether I could make a pin wrench type tool,  but am doubtful. Slots are approx 3.5 mm long, 3 mm wide and  no more than 3 mm deep, so that's not much area to apply force to. The groove is supposed to have a special locking washer, according to the parts book. Mine had none and clearly pearly didn't need it ! Looks to me as if you may have similar trouble when you come to remove that clutch ball retainer.
Old bikes; as you say. At least I had a fun ride out on my Ariel VB in the morning, before the Sloper disaster.

[Paul.W]

I've made further progress.  To get anywhere with my problem I had to get the mainshaft out which meant removing the clutch.  My "manky washer" was actually the locking washer you referred to.  Underneath was a retaining cup like yours.  I tried (gently) tapping it with a brass drift and it very easily came undone.  It is actually the bearing outer so it can't be tight. Once it moved it was only finger tight. As you unscrew it you will then find a very large number of ball bearings will fall out.

Behind the clutch is a wooduff key and a felt washer.  Remove them and the shaft will draw out from the other (RH) side of the gearbox, along with the selector shaft, forks etc.

[BEVANC]

Hi Paul, good to hear you've got your clutch apart without any drama. Would it be possible to post a photo of the bearing cup, so I can get a feel for what I'm dealing with ? Mine is absolutely locked solid, so I may need to resort to tack welding a tube onto it so I can exert a decent amount of torque. Cheers, Bevan

[BEVANC]

Hi folks,
Such is my ignorance that it has just been pointed out to me that the jammed outer bearing retainer is screwed onto a clutch sleeve, not the gearbox mainshaft itself - obvious when I think about it. Found an image of the sleeve in the 1929 parts book.

So instead of immediately stressing how to unscrew that retainer, I should be able to pull the basket and bearing off the mainshaft taper as a unit and work on it on the bench.

Ah well, at least I sought advice rather than breaking out the Birmingham screwdriver .
Cheers,
Bevan

[Paul.W]

I should have realised that myself, but I had no trouble undoing mine.However, here are a few photos of the dismantled bearing carrier, and a general view of the gearbox internals.

[BEVANC]

Hi Paul,

Thanks for those pictures - a big help.

Also, since you have things apart - could i see a photo of your kick start quadrant to compare with mine once i get it off ?  My ks does not engage until the lever is virtually horizontal, so I'm guessing that a few teeth at the start are missing or have been ground down.

Many thanks,
Bevan

[Paul.W]

A few photos of the quadrant in situ and separately. On one you can see the relationship between the teeth on the quadrant and the slot for the cotter pin that locates the kickstart lever.  Like yours, mine doesn't engage until lever is nearly horizontal, like you I thought I might have a few missing teeth - but I haven't so perhaps that is simply the geometry of the gearbox.  I'll think further about this when I come to put it all together.

I seem to be posting a lot of photos.  I don't know what the site policy is, but I'll give it a few days for you to copy them and then I'll delete them.  If you want high definition versions tell me and I can email them separately.

My biggest problem today has been replacing the felt seal behind the clutch.  Its about 5mm think and no craft shop I tried stocked felt that thick.  I eventually found a chap in Scotland who restores pianos who is sending me an offcut which might be suitable to make one from.

[BEVANC]

That's really useful Paul, thanks very much for the extra info and photos. My bike even started once when I forgot to release the decomp lever, so I guess the lack of ks travel is no big deal !
Others have posted lots if photos, so I don't see any reason why they could not remain in case they are if use to others. Many thanks,
Bevan

[BEVANC]

Just an update. I got the clutch and bearing assembly off as a unit without any drama.

When I removed the gearbox mainshaft, this is what I

found - see attached.  Not sure if this was the cause of the jamming or a consequence as yet.

Bit disappointing, to say the least.

Any suggestions welcomed !!

Bevan

[Admin]

This isn't going to help with the gearbox issue, its just to say there is no need to worry about the amount of pictures you post on the Forum, the more the better. There is no policy to remove pictures, they will stay there in the hope someone else may benefit from them.

Rob
Forum Admin

[BEVANC]

Hi folks,
Is there anyone who can tell me if in fact the damaged gear shown in my last message and its counterpart are in fact pressed onto the mainshaft as a unit ? It looks as if they might be, but the 1929 parts book lists them as one part number 25-4052.
Any advice would be much appreciated.
Cheers,
Bevan