how do u properly break a 400ex in

 

Ride it !!!!!!!!

 

You have two very different opionions on how to properly break in a motor. Your either on one side or the other. One side says you have to slowly break in a motor to allow the rings to properly seat. The other says break it in like your are going to ride it all the time.

I have been around cars for around 14 years. I have always given the motor a chance to seat the rings. On my Ds I ran two tanks of fuel through the motor before I went full throttle.

1 start the motor allow it to idle, until the motor reaches normal operating temp. let cool down. repeat twice.

2 idle around for around 15 minutes and allow to cool repeat twice.

3 1/4 throttle for around 30 minutes and allow to cool

4 1/4 throttle for around 1 hour and allow to cool

5 1/2 throttle until first tank of fuel is used up. (may take a few hours)

6 2 tank 3/4 throttle or less for entire tank.

7 change oil and have fun

You will probably get a few opionions on this matter. So read into what you will. It cant hurt to take it easy on the motor for awhile. Never hurt any of the motors I have owned. Good luck.

 

ok thanks a lot

 

ok thanks a lot do you have to change the oil after you break it in what is the advantage that you do change the oil

 

BigDs is right, you'll get varying degrees of break in methods. The reason you change the oil soon the first time is to flush out any debris from inside the motor. When put together and as parts wear in they create shavings etc. Dirty fingers, etc etc. It's a good idea to change the oil at least at the 10 hour mark if not sooner. As for break in, don't baby it but don't hammer it either, just go out and ride around run through a tank or 2 of gas before you go wide open throttle and rev it to the moon.

 

im with airaptor. I was at the same crossroads as you about 6 months ago. Just gettin my raptor and wanted to break it in properly. At first, it seemed logical to progressivly break it in so there isnt any strain on anything. I asked the question on these forums and a decent amount of people said its just the opposite. I was at this point unsure and skeptical about which was right.

Someone then sent me a link, which ill try to find, which had info to back up this new theory. (ill try to find the link, unless someone else has it) I read it all, and it was a lot to read but in this end i took its advice. It had a lot of information that contradicted the usual way of thinking. (not just with break in, but with performance mods) So far, so good. its best to read the facts on both sides and make the decision for yourself...its YOUR quad.

btw, i also remember something called heat cycles being important to the process too.

 

ok here it is...http://www.mototuneusa.com/break_in_secrets.htm

this is definately my top site for interesting, but useful, against the grain info.

o and heres the link to my thread i posted back in the day. Just in case you want to see more replies on the topic. http://forums.atvconnection.com/mess...rd1=break%20in

 

I agree with mototunes description on how to break in a motor. I went by it on my last rebuild sort of. As for your heat cycles he discredits them in his article if I remember right.

 

I too read the article, but I still felt that slowly bringing up the motor was a more affective way to do things. What happens if you go out and start running the motor wide open without proper valve lash. The motor destroys itself before you know what happens. My buddies 512ex dropped the motor on the first pass he made during his break in. If he would have taken his time He might have noticed the problem before it destroyed the motor.

I said you would get a few varied opionions, Talk to engine builders and guys that have been around the game for awhile and let them help you some.

Try Bob craycraft, MBRP, he can probably help you.