Jumping out of second gear

[DaveyT]

Hi, I followed Deefers instructions and it really helped me, the only thing is, I have re-assembled the bike and it still jumps out! Any ideas would be greatly received

[Bretty]

The dogs will be worn where the gears engage side by side. The dogs are nice and square but each time it jumps out it'll wear a chamfer on the edges, it gets worse and worse until they no longer stay engaged under any torque... As it jumps out it'll likely be bending your new fork. :-S

You need a new gear box! I'll take a photo of my knackered gears, if it makes it clearer...

[DaveyT]

Thanks for the reply, I have a full assembly but the thought of taking out the full engine to change the internals of the box made my balls shrink so just changed the forks while the engine was in situ hoping that that would sort it, photos would be good so I can Identify better.... cheers

[Bretty]

This photo shows the worn bits. The three dogs on the top of the left gear should have sharp edges. You can see the rim underneath that the fork runs in. The fork pushes that lefthand gear across on the shaft so the dogs engage into the holes/slots in the righthand gear. This should also have sharp, not rounded edges in the holes. The combined wear means under any torque they are forced apart and it jumps out into the next hole.
I thought my bike was misfiring!

It cost me £80 for a donor engine, plus a head gasket, a tube of that liquid gasket stuff and three days to get the engine out/in and switch the gearbox in mine. It would be certainly easier if you can do it in your kitchen!

 

[Bretty]

I was quite smug about finding the problem on my bike, then changing everything over. Things like that don't normally work out for me.

[DaveyT]

Thanks for the info and pics, I think I'm going to have a sulk about it for a few days then make a start on removing the engine.