How To: Break in your ride

Got that new piston, can’t stop bragging to your friends how much power your bike is going to have? Well, this break in procedure will ensure maximum power and performance out of those new engine components.

Breaking in your engine should be done after replacing a piston, rings, anything in your reciprocating assembly such as a crankshaft or bearings, or a new cylinder. Once you have fully assembled your bike, CHECK CHECK CHECK everything to make sure you are not missing parts. Look around your work area just to make sure nothing is left. Once you are sure that every piece is back on your bike its time to get ready for the break in. Make sure your bike has a NEW filter and oil in it. Once your bike is filled with lots of fluids its time to head out. Don’t go to the track, if you can avoid it, just try to find a road where it’s legal or semi-legal to ride. You are looking for a flat stretch to ride on.

The break in procedure for 2 and 4 strokes is the same. Start it up, listen to those new engine components. Sounding pretty sweet aren’t they? Let your bike warm up slowly, no snaps of the throttle like you like to always do to warm it up, just be gentle. Once warmed up start making passes back and fourth at about ¼ throttle for about 5 minutes. It’s recommended that you let it cool, but myself and Jimmyhoffa see no real reason behind this. We understand what people think it does, but it really doesn’t do anything for you. Next start to make some ¼ to ½ throttle passes for about 10 minutes. Try to only use the throttle range specified. Once you have completed that, check everything on your bike again to make sure it is all still good. Next is what you have been waiting for ½ to full throttle passes for about 5 minutes. Listen to make sure everything sounds good during these passes. Well, here is the super secret magic break in part that really makes your bike run great. While making some ½ to full throttle passes, shift up a couple of gears to where your bike is starting to bog even at full throttle. Keep it pinned even while it is bogging and hold it until it cleans up. Do this about 15 times and you will be blowing all your buddies away with your new found compression.

Afterwards, at least thumpers change your oil and filter for sure, 2 strokers I would recommend you change your oil but it is not necessary. There you go, you’re done. Trust me this procedure works. I have used it many times, and plan on using this same procedure to break in my bike which I just spent $2200 in parts on. Ya it works and I trust it.

ya, apparently a lot of people just take the bikes right from the dealer and go ride. it is the worst thing you can do to your bike. remember that any engine should be broken in, including a new car!!!

apparently thats the worst thing you can do to a new engine. pistons get glazed a lot of the time when they are driven like that. my dad built many many racin cars back in his day and he would go up to the country on the windy, hilly roads and just punish his cars, keeping them a gear higher than they should be. sometimes he would even swap out the rear diff gears for a highway set. he knew what he was doing, his cars were amazing. he had a mach 1, wheelied in 1st, 2nd, and 3rd gear and there were only 4 gears. apparently he saw many people glaze thier pistons over just driving it though. i got screwed like that once though, when i had a nitro rc car. they were like we have to break it in for you for the warranty to be valid. half way through the summer compression was like zero, and thats no good on a nitro car. i broke in the next engine using the same technique i use on my bikes and it ran fine for years.

could you please explain why its recommended that you let the bike cool off? and why you think it dosent matter?

did it work well with your bike?

well a lot of people believe that "heat cycling" the rings will give good seating results but if u look at the actual breakdown of metal, this does nothing for it. also lots of other people say it does nothing. really all u need to do is check it between runs for any leaks or loose bolts. yes my break-in procedure worked quite well for me.

well the yz will get the same treatment then. Thanks this is really helpful

no problem

real break in proedure

hey tigmaster i have two bike that i will be rebuilding before the next season
one's a 92 yz 125 and the other is a 93 kx 500 what oil ratio should i use on these bike for the break in and after. and also that break in procedure about how long total time does it take. thanks for the info

u can easily get away with 32:1. a lot of people dont even change up their mixture for break in but its really suggested. after, if u plan on using synthetic then u can run anywhere between 40:1 and 50:1. mineral oil, stick with 40:1. wat did u run before? if it was different then u need to rejet, heres the how-to article on it: http://www.mototips.com/how-tos-performance-forum/2173-jetting-your-ride.html

as far as break in time, around an hour. i think i list times in this break in article.

yes, lets all remember that lesson!!!!!!!!!

ya i had to learn the hard way remeber

ya, i still can believe that you had your engine be destroyed by mixing 2 different OILS. its not like you didnt have oil, just to sets of them that combined with the gas differently. think about other oils, such as synthetic blend. they mix synthetic with mineral oil....

ya i will definetly stick to one 2-cycle mix on my 500 when i get it rebuilt. i can't wait to feel the power. i just want tho thank you and wr250f95 for all your guys knowledge. oh ya how can you tell if your putting the piston in backwards. thanks

there are alignment marks, either a dot or arrow that should go towards the front of the engine.

Great article. Mostly.

As a machinist who deals with metal heating and cooling, expanding and contracting, and literally changing it's molecular and even it's metallurgical makeup on a daily basis, I can assure you that letting your motor cool during the break in period DOES do a lot more good than not letting it cool.

All one needs to do is study the effects of thermal expansion, annealing and other effects of heat on metal to realize that the motor should be allowed to expand and contract during it's break-in period uniformly. That's why it is suggested that you "let the motor warm up completely" before breaking it in, because you don't want some of the parts warm and the other's cold.

Different metals, and indeed, different thicknesses of the same metal, will expand and contract at different rates. So letting the motor sit for 5 minutes while you look things over will allow some parts to contract from cooling, while others remain hot.

Then you jump back on and start going 1/2 or full throttle, and you're essentially running it with the smaller parts cold and the bigger parts hot. Not a widely recommended procedure.