cooling overflow bottle

Related but new thread.

My 912ULS overflow hose is milky white hard plastic.  I want to replace it but can't really identify the part # from the IPC (no photo of a bottle like mine and no photo of a hose).  Auto parts stores don't seem to stock this hard, vacuum, high-temp hose.   Any help appreciated.

Bottle is top spout, with the hose just shoved into the cap.

David,

Any good quality coolant hose (sometimes called heater hose), of the correct ID, will do the job - it need not be translucent/clear.

I preferer Gates hoses.

To allow for engine movement/vibration, you should use a flexible hose (not hard plastic).

See: https://legacy.rotaxowner.com/si_tb_info/serviceinfo/si-pac-009.pdf

For the  expansion reservoir (bottle) to work correctly it must either have top fitting like this:

or a bottom spigot/barb similar to this Rotax style one:

A transparent bottle, where you can check the fluid level is best.

Make sure your bottle has sufficient capacity (see Rotax reference above)

In all cases, the top of the bottle must have an open to atmosphere hole/spout.