Top end break in

[TravisFader]

Hey, probably gonna sound like a real silly question but whats the correct steps for breaking in a new top end. Ive heard a few differing opinions on it.

Ive heard running it on idle till she gets hot, the shutting it off and letting it cool down for a spell and then redoing this a few times. After that take her for a smooth run varying the throttle lots and not winding it out.

any thoughts?

 

[dezmitchell]

ride it like you stole it you goon

 

[cdnemsguy]

ride it like you stole it you goon

Dez is right, sort of. It needs a load on the rings to put the pressure on the cylinder walls, especially with the Nikasil lining most have. So ride it like you stole it and dont do excessive idle time or the rings wont seat as well. Of course heat cycles are important, so drive her hard, full temp under load, let it cool completely and ride. Will be good then. But hey, I'm no mechanic, but I did stay at a Holiday Inn Express last night.

 

[markoo]

This is what Arctic Cat recommends.

 

[imdoo'n]

not what i'd be doing, can't see ya doing your top end any favours. maybe that is why my doo beats any artic cat i've ever raced. they are so slow. j/k

 

[KatMan]

Not sure how clear this image will be

Rings are not perfectly square on the outer face when new. They are slightly notched or rounded. This is why you need to put them in with a specific side facing up, to aid in break in. When your cylinder is honed(cross hatch) the ring will(should) wear slightly to adjust to the slight imperfections in the cylinder wall. Once these imperfections are worn into the the piston ring face, it is broken in and should not wear/move any longer.

I put in a new top in mine last year and did as you mentioned. Bring up to temp at idle-3500 RPM(revving up slowly) track up, cool down completely, repeat 2-3 times. Ride easy first hour on trail. Then giver. My comp went to 120 and stayed there all season.

There are different opinions on this, but that's what i did, seemed to work well.

 

[cdnemsguy]

Not sure how clear this image will be

Rings are not perfectly square on the outer face when new. They are slightly notched or rounded. This is why you need to put them in with a specific side facing up, to aid in break in. When your cylinder is honed(cross hatch) the ring will(should) wear slightly to adjust to the slight imperfections in the cylinder wall. Once these imperfections are worn into the the piston ring face, it is broken in and should not wear/move any longer.

I put in a new top in mine last year and did as you mentioned. Bring up to temp at idle-3500 RPM(revving up slowly) track up, cool down completely, repeat 2-3 times. Ride easy first hour on trail. Then giver. My comp went to 120 and stayed there all season.

There are different opinions on this, but that's what i did, seemed to work well.

This is correct but if you have a newer machine that has the Nikasil lining, cylinders are not honed with a cross hatch and therefore the rings require a load on them to put the pressure against the cyl wall, and transfer the heat through the rings. Too much idle time could potentially glaze the cylinders and rings. Just needs some load on the engine.

 

[m7 carver]

my cylinders are honed and they are nikasil coated, just did the top end on mine and we ran a hone through it just to make sur ethe rings will seat