Gear problem when cold, sticky gear


I have a PX125 disc. When the engine is cold I have problem with changing gear from 2nd to 3rd and from 3rd to 4. It seem to be stuck and I cant move the gear selector up. After about 5 min. when the egine is hot the gear change are smooth. I have tried to change egine oil and adjusted the gear-cable. Can anybody help me whith this problem?


I have the same problem with Siggen and I also think the clutch is the culprit. I’ll replace the clutch with new friction plates and plain plates. I’ll update you guys as soon as I’m done.

I have changed the oil and tiny particles of metal are visible. Looks like the clutch is in really bad condition. I couldn’t rebuild the clutch yet, still waiting for new parts.

Chenged the clutch plates and I have still the same problem. The old clutch look very nice and did not look wearn. I dont think it is the cruciform. Can it be the  gear selector-box? 

The scooter have covered about 11000 km. I think the problem is the clutch.

The bike have gone for 6900 miles (11000km). I dont think is it the cruciform because it dosent jump out of gear.

Tiny particles of metal does not sound good !! Check that the clutch bell is not worn where the tabs of the friction plates sit , it could be that the the tabs are sticking on the wear slots . The cut outs in the clutch bell should be smooth.

Have you tried without the selector cover on? if using the wrong solderless nipples they catch on cover,

also have you tried with the selector box off the scoot to see if the cables are fine?

is the clutch disengaing when pulled in(if not it will creep forward when reved at a junction with clutch pulled)?

the big question is how frequent do you use your scoot?

Can you tell me how miles /kms the bike has covered , and also how long it takes to get warm enough for the problem to go away ?

Problem solved, finally. Gear changing is easy even with a cold engine. Yup, the clutch bell is worn as well as the plates. I've replaced the clutch bell (reinforced), new springs and plates. I also checked the cruciform since the engine is in half anyway, replaced it too since its worn out.

Now the Vespa have clutch drag after a changed the clutch plates. I thightened the clutch wire but still clutch drag. Then I changed back to the old clutch plates, but still I have alot of clutch drag!!? What can be the problem?

YES :slight_smile: at last the Vespa is working ok. The problem was the new clutch plates. Changed back to the old ones. Adjusted the cluch cabel (loosning the wire) and now the gear are smoothe like butter. Cant realy understand that it was only the cabel, but I have taken of the clutch 4 times and adjusted the gear selector box and now evertihing is ok. Thanks for all the good help. :slight_smile:

Bro, have your cruciform replaced. You said the bike has gone for 11,000 miles, the cruciform would be badly worn with that mileage. If the culprit is the selector box, you should experience your problem  in all the gears, not just 3rd or 4th.

Yes , the clutch would be the main suspect - sounds like the plates are sticking together until the warmed oil separates them. New plates and new oil  I think ?

I had a similar problem a few years ago. I had routed the gear cables too close to the exhaust downpipe, which melted the outers. When the motor was cold the cables were very stiff due to the melted plastic which had hardened and interfered with the inners. Once the motor got hot, the plastic melted and cables ran free.