Hi,

I'm looking for a diagram showing the assembly of the OS 90 four stroke (circa '84). Also any tips on the reassembly would be greatly appreciated.

Thanks

Also.

The bridge supporting the rockers has a single "dot" on the centre of one face ... does the dot face forward or to the rear?

thanks

Are piston rings still available for the 90 FS?

It appears (from an old OS part listing) that the piston ring for 90 FS is the same as 91 FS (1st Surpass model) and OS 160 T. Can anyone verify?
Thanks

The piston ring for the O.S. Max FS-91 also fits the older FS-90.

The FS-90 exploded diagram can be sent to you via email. Please send an email to the Hobby Services address below, and we can transmit one to you.

The dot on the rocker arm support would go towards the front of the engine.

Bax,
Many thanks for your speedy reply. My e-mail is on the way.
RTD