Gearbox shimming

[Jordan]

Jordan

Third of the dog face! I'm obviously too fussy with my dogs

To be clear, that's the sideways width. The undercut bit, not the side face.

Jordan

[PhilR]

I am in the process of rebuilding my 350 narrow case racer. I found a chipped 4th gear on the layshaft, which I was able to replace with a NOS one from Phil Hitchcock, Road and Race in Melbourne Victoria (Australia). When reassembling the box I thought I might need to re-shim it, but Nigel's wisdom below convinced me all was well with a bit of play. The only thing I was a bit concerned about is the meshing of the 5th gears. I expected them to mesh across their full width, but they only appeared do so over about 3/4s of their width. Then after much fiddling and head scratching I discovered that the 5th gear recess machined into the hub sits slightly over the ring spring clip on the driven shaft, this moving the gear closer to its 4th gear neighbour on the shaft. Wasn't obvious nor mentioned in the manual but everything lines up perfectly now. Thought others might benefit from this insight..
PhilR

[PhilR]

Further to my previous contribution, I have suffered gear box problems whilst racing at Mount Gambier (South Australia).. Missed gears 3rd to 4th and 4th to 5th on the up changes, also occasional missed gears on down changes to 3rd (exciting as the brakes weren't up to much either. Anyway, pulled it all apart (again!) and found rounded dogs. Phil Hitchcock (Road & Race) came to the rescue with some new/ serviceable gears that he arranged to have the dogs undercut on. Next outing, Broadford in Victoria was much better. Gears clicking in and engaging and I also managed to get the front brake working quite well. had some other issues which I won't bore you with, but undercut dogs are the way to go for racing for sure.