2 stroke gearbox problems

[tomturner100]

hello, my bike is a small 2 stroke with manual gearbox that i always thought was a 5 speed and 5th gear lately doesnt work very well, doesnt feel like it clicks in properly and jumps around asif its jumping teeth or something, so i now have the gearbox apart expecting to find some bent selector forks or some broken teeth or something and cant see anything that could be the cause, also i have noticed there is 6 gears in there, anyone know what another cause of this could be?

[The Artist]

Poorly adjusted gear lever mechanism?

[Frost]

Could be lever / clutch, or could be actual gears. I had exactly what you describe happen to me. The bike was worthless with a buggered gearbox so i pulled it apart found the smashed up gears, replaced them, reassembled it and it was perfect.

[Teflon-Mike]

What's the bike?
There'll be a ratchet & pawl mechanism on the selector shaft that moves a selector drum round a notch at a time shifting the selector forks side to side to engage & dissengage the cogs.
If the forks aren't bent, they could still be worn.
The selector drum could be worn.
the ratchet mechanism could be worn, bent, misealighned.
Shafts could be floating on worn bearings.
engagement dogs on cogs could be worn.
Have you got the manual for it?
What does it say?
You could be down to measuring shim thicknesses and shaft run-outs and stuff. Looking for misshaped plungers, or pawls etc etc etc.
LOADS of things, not necesserily 'obviouse'.
Top of the list though would be the selector ratchet. Oft needs critical alignment & adjustment & indexing with the selector drum, easily got at from pulling primary cover to investigate in ignortance & buggered up!
Basically you aren't giving us enough to go on.
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