GB Gearbox Help Needed

[BSAfrica]

The gearbox is a Burman GB type, part of a basket case rebuild of a '54 Ariel KH500 plunger project. When I first opened the gearbox, there was evidence that at some time the gearbox was half filled with water, thus the "high" water mark. The kickstart ratchet pinion nut at the time of stripping was not fully home, thus, when assembling the gearbox, this nut was fully tightened and secured with a tab washer. Problem was then that the kick start ratchet would not returned to the home position as the kick start ratchet pinion and kick start ratchet drive would not disengage. Only way to get this to happen was to slacken the nut, however, this results in the ratchet drive and pinion not fully engaging, causing them to slip when pressing the kick starter. Bushes and bearings were replaced, as well as all items showing excessive wear or corrosion, including the kick starter ratchet drive and spring.

Question: Should the ratchet nut be tightened fully home, which in this case does not allow allow the ratchet drive and pinion to disengage, or is there something else that I need to look at? Just does not seem normal that the nut should be halfway out to get the system to work.

Advise and suggestions will be much appreciated

Barend

[BSAfrica]

Just another picture of inside of the gearbox

Barend

[yebbut]

rachet nut should be fully tight, check you do not have the spring trapped.

[rogerwilko]

And the bush isn't too long or short.

[BSAfrica]

Thanks for the replies.

According to the diagram for the GB gearbox, it appears that the kick start ratchet pinion is suppose to slide on a separate bush, kept in place by the spring. The one in my gearbox is a single piece, pinion and ratchet is one. Measuring the the length of the pinion and the ratchet drive, found to be about 0.5 mm too long to give enough clearance for the system to release. Bit of home engineering (using a bench grinder) to take off the 0.5mm, assembled and seems to be working just fine. Could be that with time, the thread was cut deeper, thus when fully tightened, not enough clearance was available.

[BSAfrica]

Time for an update. Kick start is sorted out, and not by the way I did it as per the previous post, that turned out to be more of a bodged job than anything else. Bottom line, pinion was seized on the bush as a result of water ingress. Got a new bush and pinion ratchet, all works fine, at least, everything in that part is new.

Next milestone is to get all the gears to engage without having to bend the gear selector lever in the process.

Cheers from South Africa

[rogerwilko]

When checking for selection,spin the mainshaft to help gears mesh.