I'm having a bit of a fight with the 1937 Burman Model H gearbox on my AJS. I seem to have lost 3rd gear. I can't see anything wrong inside it, the cogs are all there and in good nick, but I am getting a Neutral instead of a 3rd. I know it's almost impossible to say as you can't see into my gearbox from where you are, but I just wondered if anyone else has ever had anything similar in a lightweight Burman?

Does the lightweight have this mechanism in it? If so the pin i'm pointing at often comes loose in the housing and you will have to remedy that.

Thanks for the reply Douglas, but the part you've kindly photographed doesn't look familier. I'm sure it will be something like that though, hopefully it's just a pin or a connecting rod moved or something?

If it's handchange it wouldn't have it.

Could it be the detent spring gone weak or broken? This would allow the drum to possibly revolve too far and leave it in between gears, I know that it should affect all the gears, but it may just be the design that when it's in third it can move a bit more to miss the gear. I do have a fair few NOS Burman bits if you can find out what is up with it

email (option): davmax@ntlworld.com

Thanks for that Dave. I've got the bike booked in for MOT on Saturday, so I don't want to open the box and end up not able to get to the garage on the day. I'll take it easy and limp there in second and I'll open it up and have a good delve when I get back. If I find anything untoward I'll certainly be in touch with you. Cheers