hey guys, i recently put a new meteor piston kit in my ms880 as the previous piston put in by the PO was a cheap Chinese golf brand and it was scored up and actually had a crack in it...it was running ok however was low on compression hence why i put a new piston in. While i was doing this i also put in two new crank seals, exhaust and base cylinder gasket. Saw is now at 165 PSI compression HOWEVER there's now a strange rumbling noise ive not heard before and it wasn't there before, nor is it present on my other ms880.
The saw seems to be running lean and doesn't want to idle if the screw is set low and it cuts out sometimes and bogs out. When it cuts out it can be hard to start again but will fire up easily if the choke is on... prior to the new piston it was actually running pretty well. I didn't remove the carb. In this very poorly taken video you can hear the low rumbling noise and it seems like its coming from the flywheel side. I swapped over the entire clutch side from my other 880 to this one and the noise didn't go away so i can clarify its nothing to do with that side. There is also 0 play in the crankshaft either side, no up down no left right its all tight so im assuming that means the bearings are good? but it sounds like a bearing rumble...
Has anyone experienced this before? Im going to try and get a vacuum/pressure tester and test for air leaks as i feel its running lean and then move on to the carb and check the impulse line, does this sound like a good plan of action?
cheers everyone!
ms880 rumbling noise.mp4
and heres the old piston i pulled out...cylinder wasnt bad at all, came up good after a little scrub up.
WhatsApp Video 2025-04-25 at 19.59.07_f0af2ef4.mp4