I have never really got to grips with bedding in engines.
I have rebuilt many, many chainsaw engines and just fired them up and gone to work with them with no bother at all (used genuine Stihl pots and pistons, but of late used Chinese ones, again with no problems.).
I have rebuilt bike engines, but run them in first. Usually with no problems. Though the M20 seems to mark up at one side (valve side) at the very top of the piston above the rings.
Tractors (i.e. diesels) I put them to hard work straight off. However, one of them when I put it back to haulage, oil spraying out of the exhaust. I have rebuilt it twice and same thing - all exhaust ports weeping oil (injectors rebuilt, head refurbished, new liners, pistons and rings).
Bore glazing is a real pain in the arse. Do you cane engines on rebuild or bed them in gently? Depends on the engine I suppose!
Chainsaws run seel rings in chromed or nikasil plated bores.
I now fit them dry and ride the bike like I stole it.
The 2 big problems are too fine honing and mechanics leaving the bike idleing for 20 minutes while they stuff around with the carb.
No high compression loads = no high pressure behind the rings to force them into the bores.
Thus they slip up and down , barely touching the bore and glaze it before you leave the workshop.
When you rering a chainsaw, you start it, work the throttle up, down up down for a few minutes till it is warm then WFO while you adjust the main - high speed jet and then worry about the idle.
Bike owners start the bike then spend 20 minutes adjusting the idle so it will stay running without your hand on the throttle, exactly the beast way to glaze the bore.
Put your hat & gloves on, start the bike, if it actually starts runs, jump right on and give it some full open throttle to get the gas pressures up behind the rings.
Most of us can hold the throttle open just enough to stop the bike stalling out at traffic lights.
