to break in my new top end what 2 cycle oil ratio should i use?

 

I don't change the oil mix for break in. The thing I do is slowly break in engine. What I do:

Start new engine let run at idle for 5-10 minutes, lightly blipping throttle ocasionally. turn off and allow to cool completely.

When cool, start again and this time ride it fairly slowly for 15-20 minutes (Putt around). Again allow to cool completely.

When cool, start again and this time ride it below 1/4 throttle for 25-30 minutes. Again allow to cool completely.

When cool, start again and this time ride it below 1/2 throttle for 35-45 minutes. Again allow to cool completely.

At this point you are pretty much good to go. What I usually do now is take apart top end and remove piston. I then use 400 grit sand paper to remove any high spots where piston rubs on cylinder. I realize most people are not this much of a fanatic but it is the method I have been using sucessfully for over 20 year's.

Before Assembly I also sand all sharp edges on the piston except ring groove edges. I usually go for approx .020 radius on all sharp edges. What this does is take away any stress spots on the piston. Stress will always work its way to sharp edges. The other thing I always do is never oil the piston at assy, I only very lightly oil the cylinder and I mean very lightly. I have built many 2-stroke top ends this way with no problems and incredible reliability record.

 

I go easy on 'em for about an hour, then ride it like I stole it.