Post by theswede on Jan 7, 2012 12:25:03 GMT -5
I tore down the entire CVT on my china-scoot to find out why I had such a high RPM at top speed now that my EFI system is finally working.
Turns out there wasn't much in there that was OK at all, almost all parts where either worn out or broken... No wonder I was having issues with speed and RPM. And I am very lucky I caught this in time.
First thing I noticed was that the inside of the CVT cover was full of rubber dust, more than I had ever seen before in a 139QMB engine.
The width of the belt was down to 15.9mm (supposed to be 18mm when new)
The drive face gear looked like this, with pretty obvious signs of a slipping belt (the black area is rubber from the belt):
The variator back plate had cracked, and one of the variator slides where competently gone, resulting in scruff marks on the guide pin where the back plate had begun to eat into the aluminum of the variator:
Flipping it over, I saw that there was actually two cracks in the back plate. I don't think it would have stayed in one piece more than a couple of miles or so...:
The inside of the variator and the Dr Pulley sliders looked pretty worn. The sliders had lost so much material that the back plate had started rubbing into the variator at the edges:
The sliders looked bad, with significant flat spots on them:
Dissembling the torque converter, I found that the grease was all gone and most surfaces bone dry:
The guide tracks where no longer smooth and even, but pretty worn:
The guide pins looked OK at first glance, but then I found they had worn flat in places and where slightly bent:
The only part that looks OK enough that I figure I can keep is the variator drive face gear and the inner drive sheave from the torque converter, everything else has to be replaced.
It looks like this kit from Enviromoto could work:
enviromoto.ecrater.com/p/6055029/ncy-139qmb-transmission-kit
Does anyone have any experience with this kit, or alternatives?
Turns out there wasn't much in there that was OK at all, almost all parts where either worn out or broken... No wonder I was having issues with speed and RPM. And I am very lucky I caught this in time.
First thing I noticed was that the inside of the CVT cover was full of rubber dust, more than I had ever seen before in a 139QMB engine.
The width of the belt was down to 15.9mm (supposed to be 18mm when new)
The drive face gear looked like this, with pretty obvious signs of a slipping belt (the black area is rubber from the belt):
The variator back plate had cracked, and one of the variator slides where competently gone, resulting in scruff marks on the guide pin where the back plate had begun to eat into the aluminum of the variator:
Flipping it over, I saw that there was actually two cracks in the back plate. I don't think it would have stayed in one piece more than a couple of miles or so...:
The inside of the variator and the Dr Pulley sliders looked pretty worn. The sliders had lost so much material that the back plate had started rubbing into the variator at the edges:
The sliders looked bad, with significant flat spots on them:
Dissembling the torque converter, I found that the grease was all gone and most surfaces bone dry:
The guide tracks where no longer smooth and even, but pretty worn:
The guide pins looked OK at first glance, but then I found they had worn flat in places and where slightly bent:
The only part that looks OK enough that I figure I can keep is the variator drive face gear and the inner drive sheave from the torque converter, everything else has to be replaced.
It looks like this kit from Enviromoto could work:
enviromoto.ecrater.com/p/6055029/ncy-139qmb-transmission-kit
Does anyone have any experience with this kit, or alternatives?
The China-scoot actually is a pretty heavily modified 72cc, so I should see some performance improvement over the Yamaha. 
CAN YOU HELP ME OUT MAN,AS i LOST ME JOB DUE TO NOT BEING ABLE TO GET THERE?ANY INF