If remembering correctly from 108s I have had over the years, I have seen three different sizes on the exhaust valve. Here is photo of older 108 with double exhaust valve mentioned by scrane, this being the smallest size valve (20mm).
I started digging thru the storage boxes looking for 108s with the thought of seeing which ones might be able to receive the adjustable orifice assembly for the HP upgrade, but have not made much progress. This 108 would not be upgradable, no threads on the body to screw in the necessary parts in the hose inlet area.
I started digging thru the storage boxes looking for 108s with the thought of seeing which ones might be able to receive the adjustable orifice assembly for the HP upgrade, but have not made much progress. This 108 would not be upgradable, no threads on the body to screw in the necessary parts in the hose inlet area.