BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: Kevin1963 on 21 Jul, 2021, 13:18

Title: Loss of gears
Post by: Kevin1963 on 21 Jul, 2021, 13:18
Hi all
Was having a lovely ride through the lanes of Wiltshire and Dorset last night when I lost first and second gear!!!
Nursed home and eventually was stuck in third!!
Gear lever would not move up or down by this point!


Going to have a look later but quick question any ideas and if needed can box be removed without removing engine?.


1954 golden flash with swing arm
Thanks in advance. 
Title: Re: Loss of gears
Post by: DAVE BRADY on 21 Jul, 2021, 13:20
Hi Kevin,

What bike are we talking about?

Dave.
Title: Re: Loss of gears
Post by: Kevin1963 on 21 Jul, 2021, 13:21
Hi Dave golden flash have just edited original post!!!
Title: Re: Loss of gears
Post by: idie on 21 Jul, 2021, 13:39
Sounds as if the gear change spring is broken. If it has to be replaced make sure that it is for a A10 and not an A65 the A65 spring will fit but is of a heaver gauge wire and will make the gear change hard work on your foot.
Title: Re: Loss of gears
Post by: DAVE BRADY on 21 Jul, 2021, 16:41
Hi,

The spring can be replaced without removing the gear box.  Raising the bike up is ideal but on the side stand makes it a bit easier.  Obviously the oil will have to be drained.

Dave.
Title: Re: Loss of gears
Post by: royblackburn1@btinternet. on 21 Jul, 2021, 16:50
Hi Kevin 1963, I had a similar problem with my A65L the grub screw that held the  plate to keep the gear selector pawls in place had come loose  nor allowing movement don't know if your selector is the same as  a A65 hope this might help Roy
Title: Re: Loss of gears
Post by: Kevin1963 on 21 Jul, 2021, 17:11
Thanks for the replies. 

Have just got timing side cover of gear box and selector shaft has come through and jammed on pawl?.(photo)

Looking like I will have to get box out as cannot remove inner cover!


So question can the box be removed without removing engine?

Thanks Kev

Title: Re: Loss of gears
Post by: DAVE BRADY on 21 Jul, 2021, 17:42
Hi Kev,

The inner cover should come off as there are no more screws.  It could just be the fit on the shafts that are reluctant to move. Can you tap a piece of wood against it from the other side?
The box can be removed if you unbolt and remove the rear engine plates basically leaving the engine hanging on the front plates and head steady.  It is fiddly but can be done.

Dave.
Title: Re: Loss of gears
Post by: JulianS on 21 Jul, 2021, 18:17
The box can be dismantled leaving just the main case in the frame. Useful as a holding jig. It can be tight to remove the grub screw retaining the selector shaft, but it looks like yours is loose or has already come out. So unless you need to replace the main bearing the case can be left in the frame.

Easier to leave the kickstart pinion on the mainshaft and mainshaft in the inner cover and easier to reassemble that way. The shaft can be grasped in soft vice jaws to allow the retaining nut to be removed and fully tightened on reassembly.
Title: Re: Loss of gears
Post by: Kevin1963 on 21 Jul, 2021, 22:28
Thanks for all comments gents.

Managed to get shaft back in enough to remove inner cover.

Primary side off and seal has gone(bugger)

So I can dismantle whole box in situ?

If not it can be taken out and done on bench which would easier.(leaving engine in )

Sorry also can the oil seal be replaced with out removing box in case I go that route.

Was hoping to get the summer over with before dismantling to see what PO had done???


Will have to order new gaskets etc and will let you know how I get on


Thanks again for responses.

Kev

Title: Re: Loss of gears
Post by: DAVE BRADY on 22 Jul, 2021, 07:20
Good morning,

The seal should be replaceable in situ with the sprocket removed - bit fiddly getting the circlip out.  It will difficult with the inner primary case in place but as the main shaft will be out there may just be room but difficult to see what you are doing.  If I remember correctly the box can be stripped apart from the selector cam plate and the selector shaft grub screw can be difficult but as your shaft had come out of place then the screw is either loose or has dropped out.
When fitting the new seal put a bit of sealant on the edge of the flange to prevent any seepage at the edge and especially at the bottom.  Oil can sit between the bearing and the flange and find its way out to give a small but annoying leak.

Dave.
Title: Re: Loss of gears
Post by: JulianS on 22 Jul, 2021, 09:47
Fitting the seal can be frustrating because some being sold are very slightly larger outside diameter than the original making it very difficult to get it right into the housing and difficult to get it is square so it seals against the bearing and the circlip can be replaced.

The original circlips are often distorted and fitting is easier if a new one is sourced at the same time as the seal, some suppliers sell them as a pair.

There is just enough space to remove/replace the grub screw if not too tight.

There was a replacement grub screw with an Allen socket head available from Gold Star engineer Dave Flintoff a while back which is a lot easier than the orgnal slotted one.
Title: Re: Loss of gears
Post by: Pete A10 on 22 Jul, 2021, 14:15
If you have got to the point where the primary drive cases and clutch are stripped off I would take the gearbox out of the frame to work on - drop the two rear right hand engine plates of and the gearbox can be taken out completely to the right hand side. Much easier to fettle the box on the bench rather than in the frame.
Title: Re: Loss of gears
Post by: Pete A10 on 22 Jul, 2021, 14:20
Put a jack under the engine to support the weight
Title: Re: Loss of gears
Post by: Kevin1963 on 23 Jul, 2021, 10:20
Thanks gents

Box out and cleaned, bucket hands was not going to do it in situ!

Very small amount of swarf probably where selector shaft moved.
All back together dry and working.
Screw was loose not pinned over? Was going to use lock tight when ready?

Just got to wait for gaskets and then put it back in.

Also think have found where slight drip from primary case was coming from? The case has two cutouts for the oil drain? Out er cover also marked with a L on the cutout closest to the drain??? Oh well three sealing washers instead of two! Looks original.

Photos below

Kev

Title: Re: Loss of gears
Post by: DAVE BRADY on 23 Jul, 2021, 11:10
Hi Kevin,

It looks like the 'L' which has probably been done by a previous owner is near the wrong hole.  Assuming it is meant to indicate the oil level screw then it should mark the one with the hole rather than a cut out.

Dave.
Title: Re: Loss of gears
Post by: Kevin1963 on 23 Jul, 2021, 11:24
Hi Dave

yes thought that could be the case with the L but the two cut outs for the oil drain appear as though they are original a Friday afternoon job? cut the wrong one out and then cut the right one and sent on to be used????
Title: Re: Loss of gears
Post by: Kevin1963 on 26 Jul, 2021, 21:31
Well back in bike and could change up but not down!!

Cover back off and noticed gear selector plate had cracked and was bent slightly( not noticed when I dismantled.

Anyway had a bit of welding done on it and reshaped as best I can. Now changes both ways with no engine running .

New gasket on its way and then we will see?.

I'll post in wanted but going to need new selector plate.

Kev
Title: Re: Loss of gears
Post by: Kevin1963 on 31 Jul, 2021, 11:56
All back together

Quick run out to butchers and all working as it should!

Thank you for advice and comments

Kev