65SX won't down shift, need help!

Cyrperformance · 02-20-2011, 11:01 PM

Hello to everyone, I am new to this forum and hope to have to find it as helpful as others. I have a 2001 65SX for my son that i just put a 2007 engine in that was purchased from EBAY, runs perfect then I take it for a ride and it was difficult to get into first gear but shifts from first to fourth perfect, but then it will not come back down to first without a fight. Checked the shift shaft assembly in the clutch side and all looks to be in good shape, the only thing I notice is that the shift drum seems to locking up inside the transmission. What could be causing this to lock up and is this a common issue with these little bikes or is it more rider induced?

Thanks for any help.

bajadog · 02-22-2011, 07:02 AM

Not familiar with your bike, is it an auto clutch model or do you shift it?

Cyrperformance · 02-23-2011, 07:24 AM

Manual clutch and manual shift.

bajadog · 02-23-2011, 03:19 PM

What kind of oil are you running in your transmission.

I read a post on Thumpertalk where the guy used some oil with
a friction modifier in it. It caused the plates to "hydraulic lock" together.

Also you do know that the steel plates between the friction plates have
a sharp side, that must got towards the crankshaft.