Jump to content
Sign in to follow this  

I just rebuilt the top end on my 95 cr250r how should i break it in?? help please

Recommended Posts

Ok, so i've asked around and i've gotten alot of different answers... so im kinda iffy on what i should do! should i mix my first tank of fuel with more oil? and fouls plugs to do a proper break in? or is it a bad idea? How long do i take it easy on it? thanks alot need help :confused:

Share this post


Link to post
Share on other sites

normal premix ratio 35:1 or 40:1. go for an easy ride for 20mins or so not going through soft sand or boggy areas to put minimal strain on the motor. Then your good to go, theoretically you could race it straight away but I would just take it easy for 20 mins...

see here also: http://www.thumpertalk.com/forum/showthread.php?t=619612

Share this post


Link to post
Share on other sites

i was mixing 7 oz. of oil to 2 gallons of high octane fuel... the reason it blew up is cause a ring let go. so just ride it easy for 20 mins shut it down let it cool down and good to go? thanks a bunch

Share this post


Link to post
Share on other sites

um I'm Aussie, I only no metric measurements lol... just go 35:1 -40:1 with good quality oil and gas... and yea take it for a little ride for 20 mins then let it cool down. They're not that fragile, dudes have changed top ends on the side of the track then raced next race! I wouldnt do it but that gives you and idea of how tuff they are..

Share this post


Link to post
Share on other sites

yea i was mixing it 32:1 its wierd because so many people tell me different things but most people say NOT to mix the first tank with more oil. And some people say to mix it richer on the first tank of gas.

Share this post


Link to post
Share on other sites
Proper way to break in a 2 stroke.

From Moto814

1) Assemble the engine properly and torque all fasteners to specs.

2) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), shut it off.

3) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

4) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), shut it off.

5) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

6) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), take the bike off the stand and put it in gear. Take it for a ride. During this ride you want to keep the engine under a load at all times. Do not coast. Do not let the bike idle. Do not allow the engine to stay at one RPM. Riding on a mild slope is fine for this, as is slightly dragging the rear brake the entire time. Do this for about 15-20 minutes. Then shut the bike off.

7) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

8 ) Re-torque the head and base nuts.

9) Go ride.

Use this method.

Share this post


Link to post
Share on other sites

moto814 hit it. Of course over the last 20 years, I have never done this. I have slapped the engine together and warmed up the bike on the stand for a few minutes. Shut it off to let it cool. Start it up and run my moto full out. I have never been much for patience. All my bikes of different brands and displacements have run strong and with no break in related failures. This says a lot for the bike makers and the replacement parts. I always thought that would come back to bite me. Once I even replaced the piston and ring in my Husky CR250 and started it in the trailer then raced a mud moto minutes later.

Share this post


Link to post
Share on other sites

Break ins on bikes I've always done the run it warm it up on a stand let it run 3-5 minutes keeping the rpm's moving around let it totally cool off back to cold.

Start the engine up let it get warm take it out of my dirt road and ride the living piss out of it for 10 minutes take it home let it cool.

Once cold I do this again for 15 minutes. let it cool

Break in done.

I've tried the lighter break in and the rings never seem to seat as well.

Key to break in is watch the heat build up and don't lug.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×