Hi Dave

The needle valve assembly on my old YS61 is broken and spare parts not easily available.
If I remember right I have a spare needle assembly for my YS140's (somewhere...) and also think the threads are the same as with the 61....

Will this needle assy work with the 61 or is the O-ring spacing and holes different from the original 61 assy ?

From what I remember the 61 needle looked similiar to the first YS120FS needle assemblies and on the 120FS the
140 assemblies could be used.

Am i right ?

Another question that probably only Dave can answer :

This engine has the Shadel AAC piston/liner with an arched exhaust port. Haven't used it for ten years and it only flew for 20-30 flights with this setup before it was replaced by the 120AC.. I do rememeber the engine to be more powerful and less temperamental with this setup than original.

The question is : Is this setup ported for higher or lower rpms than the original setup ? Pipe considerations ?
I think I ran the engine at about 9500-10000 rpms on the ground using Asano 12.5-11 or something like that with the original setup.

Thanks..

Oistein, Norway