Hello again, I am having problems identifying a motor. Hoping it is a TZ250 motor, but knowing that the cases are similar to an aircooled RD (and the RD250/350LC).
The cylinder and top are clearly TZ250. But the cases I´m unsure about them. They are stamped with 351-501924Y. The clutch could be a give away; it´s NOT a dry one.
Jens

Here´s a picture of the engine stamped 351-501924Y:

... and here´s another:

Hello Jens-San!
I do believe your crankcases are RD.
TZ crankcases always had 2 circlipgrooves for the outer crankshaftbearings. Early RD crankcase only had a circlipgroove on the drive side pinion. Early RD crankcases also had a normal mounting in the _frame_, TD/TZ had large eyes in the crankcases for rubber silentblocs (328-15316-00), separated by a hollow shaft with 2 o-rings. So you can identify the differences easily. But as many crankcases were worn, many riders used RD crankcases later-on!
Kind regards,
Ludy Beumer

Thanks again Ludy! It´s not my motor. Been offered it by a seller 500 km from home. Even if it is rd-cases I´m a bit tempted. Maybe it has TZ-stuff inside, straight cut gears (clutch/crank) - (not likely with wet clutch?) and close-ratio tz-gearbox? Is this "bolt on stuff" or do the rd-cases have to be modified to take it?
Jens

Thanks again Ludy! It´s not my motor. Been offered it by a seller 500 km from home. Even if it is rd-cases I´m a bit tempted. Maybe it has TZ-stuff inside, straight cut gears (clutch/crank) - (not likely with wet clutch?) and close-ratio tz-gearbox? Is this "bolt on stuff" or do the rd-cases have to be modified to take it?
Jens