2003 yz125 tranny or clutch

[samual]

The foot shifter on my yz125 goes up and down without engaging in any gear, but if I turn the wheel slightly it will go into 1st or 2nd gear sometimes. Is it the clutch or the tranny? This just started out of the blue, it was working fine and then I loaded it into my truck and it stopped working.

[mephistopheles]

your shifter lever is not attached to your clutch. It does not matter if the clutch id fully engaged or not, the shifter should still change the gears. if it is not, then there is an issue in the transmission. could be either the shift shaft or one of the forks would be my guess, but it still doesn't make a shold lot of sense. if it happened when you were riding hard, then it would make a little more sense.

Hopefully someone with a bit more experience will see this and lend some aid.

hope everything works for you and it is not too expensive to fix!

[samual]

Thanks so far

[MXtras]

Is the problem with the bike just sitting there or when the engine is running or? You mentioned "if I turn the wheel slightly".....

If you are just sitting there, the shifter will only make a single shift and then requires some motion of either the input or output shaft of the tranny before it will allow another shift. This is because the transmission is what is called "dogged" (or "cogged" if you are into cars)- the gears have bosses on them that require engangement before the gear teeth make contact, and if the bosses are not engaged, the shift is incomplete. Since the shifting system is sequential, if a shift is incomplete it will not mechanically allow an additional shift until the last shift is complete.

If this occurs when the bike is in motion or the motor is running, I suggest looking at the shifting mechanism (just behind the clutch) and the shifting forks (inside - requires splitting the cases). There are lots of possibilities.

The 98-01 YZs seemed to have issues with weak shifting forks that bent easily. Since yours is a 03, I am not sure this is a likley problem, but if you have a habit of landing on your shift lever then anything is possible, for example.

Scott

[mephistopheles]

Yeah, what he said.

[mephistopheles]

Yeah, what he said.