4t jammed gearbox

[lemur]

The shift forks, shaft they slide on and the little part that follows in the groves on the shift drum would be my prime suspect.   Hard to tell much without hands on or having worked the shifter before it was dismantled.  Logically one small rough spot would not make it rough shift in all the gears, it would only affect the shifts when the shift forks hit that rough spot.

[thall1]

Dummy built back up albeit not loctited… ( still need to order the rebuild parts) all I’ve done is very gently clean up the marks on the shift drum with 800 grit… tricky trying to hold everything in place whilst spinning the mainshaft and changing gear but it seems to ok?… I’ll try again when I get another pair of hands here to help me..

[thall1]

On 11/22/2024 at 10:22 PM, lemur said:

The shift forks, shaft they slide on and the little part that follows in the groves on the shift drum would be my prime suspect.   Hard to tell much without hands on or having worked the shifter before it was dismantled.  Logically one small rough spot would not make it rough shift in all the gears, it would only affect the shifts when the shift forks hit that rough spot.

They all look good… there is just the faintest sign that the blackened surface finish is wearing on the shift forks… the guide disks are also unmarked… I’ve been trying to see which part of the shift drum is used on what gears to see if the wear marks are consistent with the lower gears and probably neutral but it’s tricky to see. I’m assuming they are as the bike rarely gets used in anything above 2nd and all other guides in the drum are unmarked