Real live experience. Maybe you want to take this into concideration..

me & a friend saw the new Honda CRF-50 (mini-bike).. & we just had to have them so that we could be idiots & have fun screwin around.. well we had the same debate on how to break in the engine.. I believe that you should run the thing hard to break it in & he didn't think it was a good idea. Yea sure i had some doubts but you have to look at the position i was in.. Full Warentee, if anything bad happend.. i'd take it back.. so i really didn't care.. it was more or less a real test for us to find out..

We both picked up our mini-bikes the same day..

dave - let his idle for a while & warm up & then rode around in circles in the yard a lil bit..

I - let it warm up for about 60seconds till it was idleing properly & took off down the street. after about 5minutes of moderate riding.. i hit the rev limiter in every gear. let the engine wind down in each gear & then road the hell out it it.. from stop to go as fast as possible.. trying to pull front wheel up & what not & varying speeds as much as possible..

dave - having a heart attach thinking that i was going to blow it up, kept riding his around shifting very easily & slowly.

4 days later & both of us have been riding our 50's each day for a couple hrs.. we lined up to race them.. & i blew him away..

Now we have to take into concideration that the bike are identical / we both went to rev limiter in each gear / semi clutch so there is no operating difference / BUT i am 20lbs lighter than dave is..

so we switched bikes & lined 'em up again.. My bike with dave on it.. blew me away..

I know that these are just a couple of 50cc minibikes but the principals are the same.. they are 4stroke engines & operate the same.

I have become a firm believer in the "run it hard" breakin theroy

thats just my 0.50 cents