Motor Break In Tips

[elchankoblanko]

A few months ago a bought a used 250R and had the engine completly rebuilt, new piston rings, crank, bearings, everything. I was just wonderin what everyone does to break in their new engine. Thanks

[TRX370R]

I start it up for the first time, let it warm up to operating temp giving it alittle rev about every 5 seconds or so, then shut it down. After letting it cool down I retorque the cylinder and head bolts, check the fluid levels. First tank of gas I take it easy, no higher then 1/2 throttle and not letting it rev too high. On the second tank of gas I run it alittle harder 3/4 throttle and up to full throttle but not letting it rev out too high. By the 3rd tank I let her have it. Don't know how everyone else does it but this has worked for me in the past.

[trx310]

break it in like you are going to ride it. Go out and take ya a little rip, come back and torque everything one more time. Make a jetting pass, and haul *** to the races. I have never done all that heat up/cool down bull. I break everything in just like i am going to ride it. I have an '88 R that is an extra bike for friends and stuff to ride with over 800 hours on it.

[papatrx]

First, since you don't know anything about how tight the motor was put together you should be on the cautious side. With a new top end, the piston and cylinder must form a shape together through heating up together. The two are made out of two different things, one's aluminum and the other steel. The two metals heat up at much different speeds and if the piston gets hot much faster than the sleeve it can squeeze it self to seizure. Allowing the heatup and cool down cycles gives the cylinder and piston a chance to change shape together slowly.

I have never run into another engine builder that recomends to ride it hard right away. You could probably get away with this if the side wall clearance was put together very very loose or if only new rings were put on the old piston.

Either way you look at it, is two tanks of fuel and easy riding worth the possibility of a seizure or shortened engine life. It's your wallet.....

[zedicus00]

yeah on 2 strokes set the cylender up TITE then break it in slowly. several short warm up cycles short riding cycles etc. on 4 strokes break in jus beat the piss outta em.

[TRX_250r18]

4 hours of half throttle is what i did

[velocityatv]

I make sure and when I'm installing it to use the oil that's used in my pre mix to assemble everything. Esspecially heavy on the rings and the wrist pin bearing. EXtra oil doesn't hurt and will just burned out anyhow. Make sure to put a slight drip of oil on the studs, that way you get true torque when tightening things down. I've broke in motors before during practice laps before a race. First I run it up to temp. Once it's up to temp I shut er down til it cool to the touch. Letting the cylinder and rings seat. REpeating this a few times and tourqing the nuts. I do this prosess 3 - 4 times, then let er rip. Make sure to run a quality oil.

[SuperChris]

Put it through a couple of GOOD heat cycles, then run the Mother ****er.

[beerock]

do not put a couple heat cycles on it and RUN IT! lol

first do a compression test, if its over 185 psi you will need to run race gas. MY SUGESTION is to run AMSOIL dominator oil at 50:1 This is the best oil on the market. once you figure out your compression psi. mix the oil and fill your tank. dont eye up the oil use a ratio rite or use a maxima pre mix(what i use its great)

start it up and blip the throttle until the cylinder gets warm DONT ride it or put it in gear. nce the cylinder is warm to the touch shut her off and let it cool completely. do this 3 times.......

then ride it varying the throttle from 1/4 to 1/2 throttle then let it cool completely do this 3 times!!

after this ride it from 1/4 to 3/4 throttle then let it cool completely do this 3 times!!!

after that ride it from 1/4 to WOT, DO NOT HOLD IT WOT just constantly roll the throttle on and off, no abrupt throttle. do this 3 times with a cooling cycle in between each time.

after this you should be done with your tank of gas, fill it up and ride it gently for the next gas tank keep rolling the throttle on. after the second tank LET HER RIP!!!!!!!!!!

[beerock]

Originally posted by velocityatv
I make sure and when I'm installing it to use the oil that's used in my pre mix to assemble everything. Esspecially heavy on the rings and the wrist pin bearing. EXtra oil doesn't hurt and will just burned out anyhow. Make sure to put a slight drip of oil on the studs, that way you get true torque when tightening things down. I've broke in motors before during practice laps before a race. First I run it up to temp. Once it's up to temp I shut er down til it cool to the touch. Letting the cylinder and rings seat. REpeating this a few times and tourqing the nuts. I do this prosess 3 - 4 times, then let er rip. Make sure to run a quality oil.

extra oil will and DOES lean out the motor. this is not good. mix the gas correctly form begining to end.

[Sanchez]

Like Beerock says start with a compression test, then air leak check the engine . With a fresh rebuild like that top and bottom you need to know that you arent leaning out the mixture with an air leak, or that fresh engine wont last long .

[elchankoblanko]

Hey guys thanks for all the info! All the engine work was done at RRP by an experienced engine builder so I know it wasnt done half assed. I was told to run race gas with a mix ratio of 32:1. I think Ill break it in like beerock said, Im not really used to the R yet so takin it slow is probly the best way to go. Thanks Again!