Cold seizure?

[jkhawaii]

my other one is being put back together. it has a malossi 70cc kit.

 

[repairman54]

First tank of gas may have oil added to the gas by the dealer for break in. We did this with snowmobiles with carbs. In fact manuals used to state this for break in of new or rebuilt motors. I'm not sure on todays FI engines. Injector systems are lean on oil at idle, oil pump volume is proportional to throttle openings. Cold seizure is an issue with snowmobiles in low temps, not enough warm up time. It takes a bit for pistons and cylinders to expand to operating temperature. Pistons expand faster than the jugs. Let it idle some in cool weather, its not going to overheat. I'm a veteran of free air and fan cooled sled motors ranging from 250cc to 500cc back in the day before liquid cooling.

 

[leroyd92]

Once upon a time I worked in a Harley shop, we had a beautiful s&s pan head motor took it's first breath of life in the shop, it idle for 10 minutes with a jug fan ( to not let the cylinders over heat on the lift ) and randomly, it locked up.

Turns out, on the assembly line at S&S, they left the zip tie that held the con rods up out of the bottom end, in the motor.

It wedged in the crank, stopping the motor.

 

[SwampSurvivor]

If it was just grabbing the piston because the cylinder was too cold, there would not have been smoke.

Back in the day, we use to throw big snowballs at the cylinder of my 175 Yamaha to cause the engine to grab the piston and stall the engine, when we took turns riding it. That motor lasted many years, and it did not seam to hurt it.

I've never heard of such a thing but I want to try it on something now. I'm intrigued.

What about snow mobiles? They ride in even colder temperatures. Are they set up looser? Two strokes are new to me, 4 strokes, diesels I know. 2 strokes seem to be quite a different animal.

I have a 2 stroke ATV that wasn't designed for cold use but I've been on it in the woods when it's 0F out and it didn't have any issues other than the throttle getting covered in snow and sticking. It's air cooled with a fan and I just made sure the fan wasn't running because it was entirely unnecessary.