break-in help

[purplefury]

i just finished rebuilding my rm 125 motor was wondering if anyone can tell me the best way to break it in as i have never done it before. I was thinking of just cruising around till i used like 2 tanks of gas, then slowly work my way up to full throttle with with the third tank.

 

[wake_rider]

i just finished rebuilding my rm 125 motor was wondering if anyone can tell me the best way to break it in as i have never done it before. I was thinking of just cruising around till i used like 2 tanks of gas, then slowly work my way up to full throttle with with the third tank.

You just need to heat cycle the new piston a few cycles while running rich premix ratio.

-Run 16:1 premix

-Run your bike 1/4 throttle until it's well warm (15 min or so) then shut it off.

-Change oil.

-Run your bike up to 1/2 throttle till warm (again 15 min) then shut off.

-Change oil.

-Run bike normally with incremental runs of full-throttle until hot (20 min or so), shut off.

-Change oil

-Now drain remaining 16:1 premix, mix premix to your normal mixture, put in fresh sparkplug, and enjoy your fresh top-end!

BTW: While running through the heat-cycles, don't allow your bike to idle for any extended period of time. You're trying to saturate your piston rings with pre-mix oil and allowing them to seat into place while your piston goes through it's first expand/contract cycles by heating and cooling.

 

[Chili]

You just need to heat cycle the new piston a few cycles while running rich premix ratio.

-Run 16:1 premix

-Run your bike 1/4 throttle until it's well warm (15 min or so) then shut it off.

-Change oil.

-Run your bike up to 1/2 throttle till warm (again 15 min) then shut off.

-Change oil.

-Run bike normally with incremental runs of full-throttle until hot (20 min or so), shut off.

-Change oil

-Now drain remaining 16:1 premix, mix premix to your normal mixture, put in fresh sparkplug, and enjoy your fresh top-end!

BTW: While running through the heat-cycles, don't allow your bike to idle for any extended period of time. You're trying to saturate your piston rings with pre-mix oil and allowing them to seat into place while your piston goes through it's first expand/contract cycles by heating and cooling.

That's quite the process, care to share why you would change the oil 3 times in 50 minutes of run time?

 

[ellandoh]

regular mix
fresh oil changes are for the trans not the piston so no need to change

start it up, blip the throttle til its warm, let it cool completely.
start it up, ride it normally under 3/4 throttle til warm, let it cool completely.
start it up, warm it up as normal, LET IT RIP

everyones version is probably a little different, this one has been flawless for me for decades :cool:

 

[2strokerfun]

As ellendoh said, lots of different opinions on this. I also see no reason to change oil between cycles (or until after a good hard days riding). The one thing most agree with is to run a couple or a few heat cycles. i.e. low throttle until good and warm; cool completely; another run at higher rpms until good and warm; let cool completely. I recommend recheck torque on base and headbolts, then ride as usual. Some think you should run a richer oil during this break in, but I never have and never will. If you run a quality oil and reasonable mix, it will have all the lubrication you need during break in.

 

[whenfoxforks-ruled]

A used RM125, would be time for a rering following Wakerider! And the rings will not seat as well, as normal (I used to be that anal on a NEW bike). X2 for the Ellandoh method. Vintage Bob

 

[Chili]

regular mix
fresh oil changes are for the trans not the piston so no need to change

start it up, blip the throttle til its warm, let it cool completely.
start it up, ride it normally under 3/4 throttle til warm, let it cool completely.
start it up, warm it up as normal, LET IT RIP

everyones version is probably a little different, this one has been flawless for me for decades :cool:

This works for me as well.

 

[jb_dallas]

I have a very hard time understanding why one would change the oil in a 2 stroke 3 times during a break in cycle. Maybe we should cover the basics of 2 stroke vs 4 stroke. I wouldnt even change the oil in a 4 stroke 3 times during break in...that could get quite expensive...not to mention the waste of good oil.

 

[1998RM250]

Agreed^^^

 

[rmc_olderthandirt]

Did the rebuild include bottom end and thus required splitting the case?

If it was just a top end then there is no point in changing the oil as part of a break in procedure as crankcase oil isn't involved in the cylinder at all. If you haven't changed the oil in a while then it needs to be changed, but not after 15 minutes of break in!

It is better to keep the load on the engine light until the rings have "seated", which really shouldn't take that long. Just go for a mile trail ride and it will be fine. Don't go blasting down a long sand wash or ride WOT down a pole line road. I always add extra oil to the first tank just to be on the safe side.

That said, even that is not totally necessary. There are a lot of race engines that are built and put to the test with nothing more than a few minutes of no load operating time.

Rod

 

[wake_rider]

I'm simply listing what my factory service manual states the break in procedure should be. Ostracize all you wish, I'm simply following what the professional mechanics who work for Yamaha decided is the proper break-in procedure.

 

[IndyMX]

I'm simply listing what my factory service manual states the break in procedure should be. Ostracize all you wish, I'm simply following what the professional mechanics who work for Yamaha decided is the proper break-in procedure.

What service manual did you see this in??

I looked at a 2003 YZ 85 factory service manual and a 2001 YZ250F service manual, neither said anything about changing oil between runs.

Both of them listed a breakin proceedure that was far less intense than yours and a lot closer to what Ellandoh listed..

 

[whenfoxforks-ruled]

Wake rider, there was a time I used to do the same anal/overkill things. A rm125 brand new, by todays standards needs minimal break in/heat cycles. More oil causes a lean condition/ unless you bother to jet for it. Breaking in the same as when it was brand new is not needed. The ring seats in minutes, just do not over heat it, or over due it! By the book, that ring is shot in hours! The oil, pay 25 dollars a quart and change it every weekend/race. Otherwise, no sniveling! Oil is cheap, other than Xamax! Then its just better insurance. ATF fluid is widely used, and cheap as it gets.

 

[Chili]

BREAK-IN PROCEDURES
1. Before starting the engine, fill the fuel tank
with a break-in oil-fuel mixture as follows. (graphic not included but they recommend 15-1)
2. Perform the pre-operation checks on the
machine.
3. Start and warm up the engine. Check the
idle speed, and check the operation of the
controls and the “ENGINE STOP” button.
4. Operate the machine in the lower gears at
moderate throttle openings for five to eight
minutes. Stop and check the spark plug
condition; it will show a rich condition during
break-in.
5. Allow the engine to cool. Restart the engine
and operate the machine as in the step
above for five minutes. Then, very briefly
shift to the higher gears and check full-throttle
response. Stop and check the spark
plug.
6. After again allowing the engine to cool,
restart and run the machine for five more
minutes. Full throttle and the higher gears
may be used, but sustained full-throttle operation
should be avoided. Check the spark
plug condition.
7. Allow the engine to cool, remove the top
end, and inspect the piston and cylinder.
Remove any high spots on the piston with
#600 grit wet sandpaper. Clean all components
and carefully reassemble the top end.
8. Drain the break-in oil-fuel mixture from the
fuel tank and refill with the specified mix.
9. Restart the engine and check the operation
of the machine throughout its entire operating
range. Stop and check the spark plug
condition. Restart the machine and operate
it for about 10 to 15 more minutes. The machine
will now be ready to race.

 

[IndyMX]

Pretty much what I found in both of the Yamaha manuals I have Chili..

 

[wake_rider]

Yeah, I was just mistaken. I just looked through my manual and it was just as stated above. I'm not sure as to where I got the idea to drain the oil. That being said, I'm completely aware of how a 2-Stroke works and changing the oil doesn't hurt anything as there could hypothetically be some type of shear that makes it's way into the bottom end through the crank. Unlikely, but not unthinkable.

 

[whenfoxforks-ruled]

Clutch wear kills the oil.

 

[whenfoxforks-ruled]

2000 CR250 Honda shop manual, "pay extra attention the first operating day/15 miles. Avoid full throttle and rapid acceleration". It goes on to say, do this when the piston, ring, crank are replaced. My 83 and 97 books, not 1 word of break in. They do have a, "change after first use", and a maintenance schedule. Keep it simple. The extra oil, besides running it leaner in the real world, does cause more harm than good. It does something bad, and I can not recall it. I could be wrong/old, but it is still over kill. There was a time, I was breaking in everything, spark plugs, clutches, chain and sprockets? Then it starts getting into being classified as a full blown "whistledik".

 

[BSWIFT]

Wake rider, there was a time I used to do the same anal/overkill things. A rm125 brand new, by todays standards needs minimal break in/heat cycles. More oil causes a lean condition/ unless you bother to jet for it. Breaking in the same as when it was brand new is not needed. The ring seats in minutes, just do not over heat it, or over due it! By the book, that ring is shot in hours! The oil, pay 25 dollars a quart and change it every weekend/race. Otherwise, no sniveling! Oil is cheap, other than Xamax! Then its just better insurance. ATF fluid is widely used, and cheap as it gets.

Cheap ATF, couple of heat cycles, ride! I can change the tranny oil every ride at a 1.39/qt. The contamination from the clutch is gone after every ride. The Pro rider/mechanics that I know personally recommend consistancy and clean fluids over what the manual discribes for PRO riders.

 

[whenfoxforks-ruled]

I totally agree 89er, except for who that manual was wrote for. The pros would have been my last guess. The pros schedules are a lot tighter!

 

[purplefury]

thanks for your help guys I will break in the motor next time i go riding. i cant break it in now because i live in a residential area and someone would call the cops.

 

[IndyMX]

thanks for your help guys I will break in the motor next time i go riding. i cant break it in now because i live in a residential area and someone would call the cops.

Smart thinkin.

 

[BSWIFT]

Should have been more specific. Non pro riders need not follow the recommended hours as closely as a pro level rider. :think:

 

[IndyMX]

Should have been more specific. Non pro riders need not follow the recommended hours as closely as a pro level rider. :think:

However a non-pro rider should probably break in his engine a little more carefully than a pro rider.

 

[whenfoxforks-ruled]

However a non-pro rider should probably break in his engine a little more carefully than a pro rider.

Nope. Aside from a truck full of parts available, and an adequate mechanic, what is the difference between the pro racing it and the guy out on the fire road? That book is sold with every bike in mind, not who buys it. It is the only true base line for keeping it safe, and running as it was bought. Some schedules this, that, or what ever. I can get more time if needed, but I also know the compromise, and I prefer to keep that on me, not someone else. A person can get 100 hours out of a ring, too what purpose? The ring may still be pushing adequate compression? The skirt is another story? How long does it take to push a cylinder out of round? Who gulped twice when they read that YZ break in, and the old rings went back into the mix, seemingly. It did not specifically say to use new ones? The pros top ends, 30 minutes plus 2 laps, not the 5 hours of bliss. I ask the guy that did the cylinder, with consideration! Break in, is break in, regardless of the operator. 100 hours from 1 rider to another, of course it is different, and regular maintenance plays a huge part. The books may not be perfect, or up to date, but its a start, and all we have.