Hey everyone! Just got my 1987 Trail Boss 250 back from the engine builder. I had the top end done and was hoping to get a couple solid opinions on what a good break in procedure would be to seat the rings well and hopefully have the engine last a long time. Thanks in advance!

 

I am reminded of my Bridgestone 80 motorcycle days back in the late 60s. Two stroke engine piston seizures were not rare in those days. We basically rode gently for the first 50 miles. No full throttle accelerations, no sustained high rpm cruising, and no severe engine braking. Your rebuilder may have made some recommendations. My Can Am 4 stroke wants 10 easy hours on the engine for the break in.

I'm sure others more experienced than me will post some good advice shortly.

David

 

Whatever else you do make sure you vary the throttle and don't run it wide open. Someone with more experience can give you the details.

 

Bleed the 10mm screw on top of the oil pump until bubbles stop and just fluid comes out.Premix the first tank of gas 50/1. Once you crank it up,at an idle hold the oil pump arm all the way up so oil can get to the cylinder faster. Vary the throttle through a couple hrs break in period. Will smoke a little extra on the double oil but protects the engine through break in. After that run straight 87-89 fuel and let the pump handle the oiling.

 

Very good reply Old Polaris Tech. I like the idea of "priming the pump" so to speak, and running 50:1 oil for the first couple of hours. The extra oil will certainly protect that cylinder wall.

David

 

You're not priming the pump,just removing any possible trapped air that could be in the lines or the pump itself.Lifting the pump arm just tricks the pump in to flowing wide open so oil can get to the cylinder quicker. We always premixed at least a couple gallons of gas or so when we set them up out of the crate as a safeguard in case of air bubbles in the oil lines.

 

Okay Old Polaris Tech: We're not priming, we are "burping" the pump to get the air out.

David