Break in procedure??

[sandy blonde]

Hey all,
Just got my cylinder back from the machine shop and my friend will be putting my top end back together for me. I'm concerned that he'll mess something up since that's what happened to his 85 ATC 250R. Maybe he learned something from that experience Anywho, I can't tell him that I'm worried about him blowing it so I'm doing my own research. It's bored to 66.5 and I've got a new needle bearing, gasket kit, and pro-x piston kit (I prefer cast to forged b/c I'm not a throttle junkie). Duncan Racing has this webpage that details the 2 stroke top end assembly and I got 95% of my questions answered there. But their link to the break in procedure and pressure testing pages don't work. Too bad it's Saturday and they're not opened again till Tuesday. And my friend's going to work on it tomorrow. This is where all you guys come in, I love this forum! Thanks!

[ky 2stroker]

well, heres how I do it. I usually start it up and blip the throttle alot, keepin the revs up an down constantly never letting it rev to high or letting it idle. I do that for about 3 or 4 mins untill the jug gets pretty warm to the touch. then I shut it off untill eveything gets cold like its never been started. I do this 3 times. then on the 4th time I get it out and ride it around, using short full throttle bursts, letting it get barely into the powerband and then I shift to the next gear. I usally ride it around 5 or 10 mins I guess, keepin an eye on how hot the jug and radiator is getting. then I park it and let it cool all the way down. then I ride it some more the same way. I usually just ride it like this, but each time letting it rev a little bit higher and more into the powerband. after you go through a tank of gas its safe to say its ready to rip in my book.

thats how Ive always done mine and never have had any problems.

[Smkmup]

I like to fire it up....Let it idle for about 10-15 minutes at a mid-high idle without touching the throttle...Then let it cool for about 20-30 mintues and repeat the same prodcedure again...After that I'll go around and re-torque all the nuts....Then I'll drive it for about 10-15 minutes shifting through all the gears and no more then half throttle...Then let it cool...And then I beat the piss out of it

[quadzilla87]

every time i rebuilt somthing or put somthing back together i mostly let it warm up to operating tempature and then hold it wide open threw all the gears i figure if its going to come apart thats when she will blow apart

[sandy blonde]

So there's no set way? Oh, and it didn't get finished this weekend. Rebuilding the carb before I throw it back in.

[nitrousbaby]

I break mine in by lettin it idle for about a minute then I take it out in the dirt and do a second gear hole shot I break mine in like its a rental quad on race day. always have my friends think im crazy but its worked for me.

[RZBansheeMan]

I've always started them up, let em warm up, start riding them moderate throttle for a few gears than give em hell, let it cool down and re torque. I mostly break them like I'm gonna ride them. Ofcourse there has been lots of debate over proper break in procedure. The way I figure it is as long as the bore clearance has been set right for the new piston and the ports have been sufficently chamferred, all new gaskets and properly torqued. After an initial warm up, it's ready to rock (assuming that no other changes have been made that require rejetting).

[RZBansheeMan]

Originally Posted by nitrousbaby

I break mine in by lettin it idle for about a minute then I take it out in the dirt and do a second gear hole shot I break mine in like its a rental quad on race day. always have my friends think im crazy but its worked for me.

WORD !!!....."Ride it like you stole it" Break in procedure for me too.

[Duneman101]

a couple of heat cycles is usually a good idea, it really helps the rings to seat.....

i warm it up, for about 15, let it cool down all the way repeat two more times, then take an easy ride around 20 or so minutes, let it cool all the way, then ride like theres no tomorrow furthermore.

[370banshee]

3 heat cycles then beat it into submission.