C15S SCRAMBLER GEAR SELECTION

[bobby12]

Hi
Still struggling with my gearbox problem, checked all the parts and all seems to be ok, can sometimes engage gears when out of engine but only neutral and one gear up when installed. Have noticed that the two plunges seem to engage on the top of the radius corners on the cam plate slots, it is a new cam plate, wondering if the quadrant should be lowered so plungers engage more onto the slot flat faces, I am clutching at straws at the moment for a solution.
Thanks M W

[Alan]

Does your gearbox have the flat positive stop spring? I had a problem with a pattern spring, the bend at the end was too long and would not allow the camplate to move fully, took some finding.

Alan

[bobby12]

Hi
Do you mean the leaf spring bolted to the rear of the engine case ?
It is new and does have curve for the cam plate to follow along, if you mean this could you let me know ?  then I will check.
Thanks,

[Alan]

Hi,
Yes that is the one, the bent over end was too long stopping full movement of the camplate.

Alan

[Spaceman]

Hi
Still struggling with my gearbox problem, checked all the parts and all seems to be ok, can sometimes engage gears when out of engine but only neutral and one gear up when installed. Have noticed that the two plunges seem to engage on the top of the radius corners on the cam plate slots, it is a new cam plate, wondering if the quadrant should be lowered so plungers engage more onto the slot flat faces, I am clutching at straws at the moment for a solution.
Thanks M W

I would have expected the plungers to engage in the middle of the slots in the camplate - that is, halfway between the front and the back of the slots. In this case, are you saying that the plungers engage too near the front of the slots or too near the back? If too near the front, this could well lead to insufficient movement of the camplate when you try to change gear making it difficult for it to index properly -that is, for the detent spring to engage with the notch in the back of the camplate.

[bobby12]

Hi
Sorry to ask again but are you saying that the spring was to long overall, if so , if mine seems to long I could try taking some off the bottom edge, did you shorten yours ? Can you member how much excess there was under the radius part ?
Thanks, MW

[bobby12]

Hi
With the gearbox out of the engine and on its side with gears etc in a vertical position then if you look at the cam plate from the front with the 5 cut outs in front of you the plungers are engaging at the top end of the 5 slots with some actually catching the radius in each slot , I  feel the quadrant / gear lever shaft needs to have some material turned off the under side of the shaft so it drops down and the plungers engage into the centre of each slot on the flat faces. If this is so I cannot understand why unless the cam plate is not as it should be ? Perhaps a badly made one, this could be my problem for not getting the gears !!
Thanks, MW

[Spaceman]

If I understand you correctly, with the gearbox internals the same way up as they would be in the engine, the quadrant plungers appear to engage too far back in the camplate slots? Any chance of a picture showing the plunger / camplate positioning?

It would be interesting to see the gearbox which might make it much easier to diagnose the problem. Where are you based? 

[bobby12]

Hi
I am in Sutton Coldfield in the Midlands. I will take a photo soon, a friend has the quadrant at the moment to try and have a look .
Can I attached photos to this site ?
MW

[Alan]

Hi,

The end of the spring where the V is formed was too long and catching on something (can't remember the details it was about 20 years ago).

[Spaceman]

Hi
I am in Sutton Coldfield in the Midlands. I will take a photo soon, a friend has the quadrant at the moment to try and have a look .
Can I attached photos to this site ?
MW

I will be travelling back home down the M6/M42/M40 on Saturday morning from the Lake District and would be happy to pop in and have a look at the gearbox if that is any help.

Attaching a picture is simple using the 'Attachment and other options' button. Just need to make sure you resize the number of pixels so the .jpg file size is within the limit indicated.

[bobby12]

Hi
If you could pop in on Saturday that would be brilliant, really struggling now. I feel the position of the plungers is not correct.
If you could visit, do you have a mobile or email address that I could give you my address, don't really want to post it.
Thanks, MW

[Spaceman]

Posting a message on the forum is absolutely secure and I will definitely be the only person who will be able to read it. However, I will post you my mobile number and you can SMS me if you prefer.

Depending on traffic, I should be with you between 11-12 on Saturday. It would be good to start with everything outside the gearbox assembled on to the inner timing cover, if possible.

In the meantime, it would be interesting to know more about the history of the bike and the reason why you have fitted a new camplate? For example, did you acquire the bike in a non-working condition and it's gearbox has never worked properly?

[bobby12]

Hi
I purchased the BSA about 3 months ago as an unfinished project.It has had a lot of work and money spent on it. I wanted to strip it down to make sure all was ok as it had been standing for about 2 years. I have only ever been able to engage I think neutral and second gear, I assume on his rebuild is when the cam plate and springs etc were changed. I did ask  him the question about the gears and he did say all four gears were working when he rebuilt the bike, do not know if that's the truth, he seemed a decent person.
Since taking out the gearbox I have been able sometimes to engage gears but not consistently.
Look forward to seeing you.
Mike 👍

[Spaceman]

I'm assuming that the gear change problems were there when you bought the bike - the previous owner may have changed the camplate in order to try to address the issues but this may not have been completely successful.

I'm sure we'll be able to get to the bottom of the problem on Saturday morning. Should be there between 11-12 am and thanks for sending me your details.