KDXRIDER.NET

I got my top end assembled over the weekend. Wiseco piston, Vforce III reed cage and Mr. Blacks magic head mod. (His work is awesome!) I ran the bike for (4) 10 minute cycles blipping the throttle and letting it completely cool in between. Last night I rode the bike for about 25 minutes pretty easy. I was going to ride again for 30 minutes, let it cool and take it easy for the rest of the tank of fuel. What to you guys do for break in?

Warm it up...RUN IT..HARD!

it seems there are 2 schools for break in: slow break in (like you did) and hard (like CC said).
I remember a good post somewhere, can't find it though anybody remember the link?

No, I don't remember the link but I think I read the same post. Something about breaking in slow wears away the fresh cross hatched pattern before the rings get a chance to wear in. I will use the fast method after my next ring job.

Gotta load the engine in order to seat the rings.

Sounds from the thread you may have just let the bike idle and blip the throttle a few times during four 10 minute cycles - if so, that is not the way to seat the rings.

Riding it around for 4 ten minute or 15 minute periods with cool off between cycles and short bursts of 0-1/2 and 0 - 3/4 throttle would have been better. That said you could check the compression on the bike now and then run 3 tanks of fuel through the bike riding it as you normally would (hopefully with some WOT when conditions and ability permits) and then recheck the compression. Only reason for doing this would be to see if your method fully seated the rings.

To answer your question - I warm it up and ride it around 15 minutes or so at low 0-1/2 throttle short bursts: then cool and repeat with 0-3/4 throttle bursts. Then warm it up and ride it normally with the exception of not holding it at WOT for more than 5-7 seconds for a tank fuel. At this point I'm convinced it is fully broken it.

There's a new search engine out...called 'Google'. It's great for stuff like this!!

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

http://sportbikeguy.com/garage/floor/breakin.html

..lot'sa stuff like that.

Of course, we all know the web is god of all things true!!

Well, might as well tear it down and do it over.... Just kiddin I'll just have to see how it turns out after running it harder this weekend.

My thinking was this time I would do the slow method break in. When I bought the bike the mechanic at the shop told me he had the break in completed when I picked it up. I took the bike on a semi easy trail ride and it puked coolant for the first 15 minutes. I thought I was running it too hard, stopped and let it cool for 45 minutes and it puked coolant again.

I thought the major point of the heat cycles was to allow the piston time to achieve stable molecular structure, like a seasoned car engine block. Learn sumthin new every day

Thanks guys.

IdahoCharley wrote:To answer your question - I warm it up and ride it around 15 minutes or so at low 0-1/2 throttle short bursts: then cool and repeat with 0-3/4 throttle bursts. Then warm it up and ride it normally with the exception of not holding it at WOT for more than 5-7 seconds for a tank fuel. At this point I'm convinced it is fully broken it.

This seems to work the best for me. I do a quick check of bolts and hoses after the first 15 minuteish run.

I rebuilt the top end of my 01 220 kdx and did a lot of research into break-in.

!st thing I did was to make sure lots of moly was appliead to all appropiate internal surfaces.
then I mixed half a tank at 16:1. I forget where I got that advice, possibly Wiseco themselves.
And as others have said to make sure that you put a load on the engine. Warm it up for one minute ride slowly at first but bring rpms up, go through all the gears and make sure after opening the throttle up to let the engine rpms come back down. This creates a vacuum and where the real seating of the rings take place. I probaly only rode it 20 minutes the first time and then let it cool overnight. The 2nd day I got on it a bit more bringing it to full throttle, but not in a real hurry. Bike has been running great since. Heard that just blipping the throttle was a bad thing to do.
There was a lot of spooge on the power valves when I took it apart. glad I did. Used 2 cans of carburetor cleaner!