Ec250 Clutch/gearbox problem

[Banwen]

Hi all,
I was out on my bike and everytime I changed down the bike would lockup.
I managed to get it back into nutral twice and headed home, but the 3rd time it locked up and the gear shifter wouldn't move.
I got the bike home by splitting the chain and pushing �� I took the clutch cover and springs out and was left with the 30mm nut. As I turned this there was a release and the gears appeared back to normal. Any ideas why it jammed??
I put the bike back together and got her back into nutral.
Now the bike is slipping into gear while I push it down the garden in nutral. Any ideas?

I believe the problem was up at the master cylinder as I lost the screw and rubber boot and made a temporary fix until new parts come. ��
Now the bike is slipping into gear while I push it around the garden while In nutral. (bike not started)

Looking forward to hearing and learning.

Banwen

 

[(F5)]

So either the gear drum is no longer retained by the detent spring or there is damage to the shifting forks. Option 1 would also be a cause of the damage. So either way with the symptoms you describe I would be pulling the bottom end down before more damage occurs.

I just can't think of a scenario that it would jump out of neutral into gear otherwise.

The gearbox is usually really tough but stuff can happen. There are a few bikes being parted out, parts manual will tell you what bikes are the same, likely most.

 

[gasser]

I have had similar problems before on gassers and it was always the scorpion gear. That's the nickname for a flat piece of metal that is shaped like a scorpion (viewed from above). It is located below the kick starter gears on the clutch side and has a stiff spring on it that returns your shift lever to its center position. This "scorpion" is stamped metal and sometimes they are a little rough around the edges. At the first sign of shifting problems its a good idea to remove the scorpion and sand/polish the edges. People who change their oil often seldom see this problem but leave that oil in there too long and the extra debris in the oil can be enough to cause the scorpion to stick. Mine always stuck in the down position and would not change gears until the scorpion was returned to the center(neutral position).

 

[Jacob 'Berg]

I agree with F5 and gasser.

Given that the transmission was locking up, I would be splitting the cases to inspect the gears and shift forks, regardless of the whether the issue was caused by the shift scorpian or selector spring.

 

[(F5)]

Fortunately these things come apart with little effort aside the occasional crank nut that I've needed assistance with.

 

[Nocams]

Also,check the small bearing on the end of the detent lever hasn?t Had the inner and outer come apart. I?ve seen 2 of these disintegrated on bikes with your symptoms.
One bike cooked the shift forks.