YPVS Gearbox Selection Problems

[headcoats]

Don't think this latest build likes me LOL

Done 600 miles on this engine with the Athena top end and gearbox was fine

Started it up today and was in neutral as usual , put it in first no problems and went up drive a few times and rolled back , repeat

Then I was selecting the gears with engine running at standstill and have lost 1st and second and neutral and 3rd , can go into 6th and 5th and 4th then it won't budge and is in a false neutral and not showing neutral light

I have been chasing a noise on this and had changed the primary gears again but the noise remained and now thinking is it a gearbox issue ?

Rocking the bike is not getting it into gear either

[muttsnuts]

take the clutch side off and check the gear selector shaft and the star on the selector drum, had one do that a few weeks back, turned out to be the star had been modified (peaks smoothed down) and the selector fork was really worn and wobbly, plus the pin holding the star in place was missing, all of that wear/movement meant it didn't go into gear, sorted it and was perfect after that - exact same fault you describe, especially trying to go back down the box from 6th

[headcoats]

It's an unmodified star Dave and was a brand new shaft and pin centralised etc
When i took the clutch off i didnt touch the selector but didn't look at it either

[muttsnuts]

um, ok, have you checked that the fork on the selector is central to the star on the drum ?

[headcoats]

Went back into garage last night and now can select gears !
Earlier i think i had tried for 30 minutes with no luck
Will start it later and test again WTF

[midlifecrisisrd]

When these gears are not spinning at speed they are very clunky

If the shift shaft is not set correctly it can stick between gears or fail to go either up or down

You did fill it back up with oil 🤣

Steve

[headcoats]

It does feel like that and yes got oil

Gonna start it up now