Compression Test Results on new motor...

[YZ125rider21]

So I did a compression test tonight. After 200 miles on the new engine build, I got 160-170 on all 4 cylinders. Does that sound about right for only having 200 miles? I figure between now and 1500 miles, they should seal up a little more and get me up to the factory stock rating of 185psi.

[91civicDXdude]

it all depends on how you break the engine in. Engine break in is a controversial subject. on one side, you have those who say be nice to the engine and it will last, and then the other side says "break in slow, engine is slow, break in fast, engine is fast".

After reading up and making my own informed discision, i say that you should rip the piss out of the engine, make several speed runs and engine brakes, and be done with it.

drive it like you stole it and she'll be faster in the end

[audioquattro]

i fully agree with the above, tear her down the road and set her rings

[spongerlbc]

Check out http://www.mototuneusa.com/break_in_secrets.htm if you dont believe what they are saying.

[YZ125rider21]

ok thanks guys i guess i passed my 500 mile marked changed the oil last night and warm it up and took it out and beat on it...sounds meaner now then before i threw the rod bearing...i just glad its up and running...gonna drive it about 800 more miles and do another compression check see what it reads but this time i drive the motor hard

[RedRacerCivic]

yea do a few more oil changes and wait til you hit at least 1000 miles, your rings should then be nice and seated, then do a compression test again.

[YZ125rider21]

hmm...i did oild change 20 mintues after i started motor to break in new head...then did one at 500 miles now gonna do one at 2000 mile mark is that about right