engine failure today..

I had the pin that holds the top ring from rotating come loose & wreck the piston & cylinder :-(

the engine had maybe 1000-1500 miles on it & when I took it apart I noticed a little play in the lower rod bearing so I split the case.... when I did I noticed that the main bearings were generic & in pretty bad shape
Im going to take the crank to my machinist & see if he can do the bearing & machine off some material from the pin side to help ballance it
Ill use all japanese bearings & I was even thinking of using an iron sleeve in the cylinder
I can see the # on the mains I think they are 3202 (common bearing) the lower rod though may be harder
thanks for reading
take care
JAK

main or side bearings are 6202

the countershaft? bearings are 6202FS which just means they have seals on both sides
the main bearings I believe had single shields & that they were put toward the inside which starved them for oil, one of them was really dry there was shields between the main bearings & the flywheels on both sides some of which escaped & got dragged around the inside of the case a bit by the flywheels on both sides
I took pics of the inside of the case & the bearings
there is no de burring at all with the castings so there is allot of potential for case material sluffing off & getting cought up in the piston .....

on the rod Im not sure I think the rollers may need to be measured
I looked very carefully at the lower rod bearings through the slot in the bottom of the rod & they look Ok as well the play in the rod is mostly vertical & not lateral so IM thinking the rod is stretched & that the bearing is Ok
Ill edit & ad pics later
take care
JAK
PS I did get in touch with the supplier & maybe hopefully he can be of h elp somehow
thanks for the condolences

I have it all back together & running accept one of the jam nuts (the one that holds on the sprocket lost tis threads as I tightened it
the shaft appears to be fine
I did porting work on the cylinder & de burred everything
just a few odds & ends & it will be better then new
take care
JAK

IM runnning 32:1
same thing I run all my stihl saws on
infact I generally use stihl oil
take care
JAK