Mine is #135 or 36. Bill says 1/2 throttle for 100 miles. Any suggestions. My 09 klxs only has 800 miles and I am the 3rd owner so I have no idea if proper break in procedures were followed.

My throttle is fully open within 90 degrees. Is that stock? If its stock does a quick turn open in 45 degrees?

 

there are so many opinios on a break in proceedure that you can find.
My proceedure is: make sure it is jetted properly and run the **** out of it under load.
This will seat the rings in about 3 dyno pulls and you will not have blowby.
Break it in fast, and it will run fast. break it in easy, and it will be a dog.
Just my opinion here, as well as many others who build race motors.
The KEY is to have the motor under load, not idling, not putting around, LOAD will seat the rings.

 

Here's what KLRCary (RIP) suggested for the 685 kit he developed for the KLR650:

"Before the first fire up, change the oil & filter. Use a cheap 10w30 or 10w40 mineral based oil. No synthetic. Warm the bike up fully. Ride the bike somewhat easy for 5 to 20 miles. DO as much engine braking as possible. NO steady throttle cruising! Change the oil and filter again using a premium grade, non-synthetic 10w40. Over the next 150-200 miles work the engine progressively harder. Best if done in 2-3 sessions with a cool down in between. Again, use as much engine braking as possible. Go through the gears as much as possible. There are no RPM limits, just “work” the engine a littler harder each time, then back off. Change the oil and filter again after this period. You can now use a synthetic oil (recommended). Use a 15w50 or 20w50. Avoid any extended high RPM runs for another 100 miles."

The kits are similar in design. Both use JE forged pistons in a steel liner.

I pretty much used this procedure for the 685 kit in my KLR and also for the 351 kit in my KLX250S. I now have 30,000 miles on the 685 kit and 7,000 miles on the 351.

Ron

 

http://www.mototuneusa.com/break_in_secrets.htm

 

I agree with Gary. Off idle of fast idle until it's warmed up, with the jetting correct run it loaded. I also believe this aids in seating the rings, but really don't have any hard facts to support this. I've done two 351 kits, and 341 kit and followed this procedure and all have turned out great. Most important thing i think is to make sure you change the oil shortly after the run in. The rings will fracture the ridges of the cross hatching in the newly bored cylinder and leave very small metal flakes in the oil. It's important to change the oil and filter after this and again around the 100 mile mark.
One again, lots of theories of thought on this, this is just my opinion

 

Pretty much everything said above is my theory on it, but i don't believe in "taking it easy for a few miles first" since i've been told by a couple of performance engine builders that "bore glaze" can start to form and will not allow the rings to "seat" properly and "polish" the cylinder correctly.

Don't hammer the throttle open all the way, just give her a good punch of acceleration and then back off and let the engine braking load the rings that way. Rinse and repeat, 20 miles should be more than enough time/distance if you want to apply liberally.

 

[QUOTE and then back off and let the engine braking load the rings that way. Rinse and repeat, 20 miles should be more than enough time/distance if you want to apply liberally.[/QUOTE]

engine braking does NOT load the rings. COMBUSTION loads the rings.
The spring tension of the ring is not near enough pressure to properly seat the rings.
it's the combustion of the "big bang" that forces the rings out to the bore.

 

Poor wording on my part. I was meaning the method of loading/unloading the engine; burst of acceleration, then engine brake, burst of accel, engine brake.

 

Warm it up and then ride it like you stole it. That will seat the rings. Easy and fun!

 

I put in a 351 kit. It ran rough at first and made a bunch of noise. The De compressor made a bunch of noise when the engine stalled. I idled it few minutes and let it cool off, then fired it up again went for a gentle ride. After 70 miles of riding it "normal", and using a lot of engine braking to keep the crap sucked out of the cylinder, I changed the oil. After 100 miles, i opened it up. Now that it has been 400 miles, it seems to be really broke in. Full RPM and regular riding seemed to be best for it. Oil will be changed again soon.

You are ONLY breaking in the rings, so its hard to hurt it.

After seing as many engines break in, If it was done right, it will not matter how you break it in. It will happen eventually any how.

"first it will wear in, then it will wear out"

Keep riding and have fun!

David