I am working on a few project saws (181), and have 3 P/C combo's and at least 4 spare cylinders for them.
My questions :
- the pistons all have thin rings and show all normal to me, except that the rings do not stick out as normal rings do (less springy). There's less material so that can be normal. Can anyone confirm ? Judging by rupedoggy's comment, thin ring piston saws should have lower compression ?
- I noticed also that the jugs have different markings on them, going from A, B up to D . I still need to clean all the pistons but noticed at least one piston that had a B marked on top, going with a B type cylinder.
Anyone know if these have particular tolerances and if the pistons can be exchanged ?
Lots of questions, looking for someone in the knowing.
thanks
From what I know - 181s come with the two thin ring pistons or one 1.5mm, the thin rings have less friction and appear to be faster running as many racers use these in their saws - mine has the 1.5mm
I would guess that with them being thinner, they have less outward spring but is worth making sure they are free moving in their respective grooves.
The A&B thing is where Husqvarna match their pistons to the cylinders, never heard of C&D, usually just A&B, it is to get the correct Piston to Jug fit to ensure a sweet running motor - many after market non OEM pistons will be manufactured to fit both A&B jugs.
Spud