Break-in Procedure

[BeanStalk]

Getting close to wrapping up the rebuild of our '04 KDX220. I've searched old posts for a complete break-in procedure, without success. Can anyone point me to an existing thread, or list the complete procedure? I've installed new main bearings & seals, new rod & bearing, new top end, etc... Coated everything inside with 2c oil, filled the trans, etc... Thanks!

[rbates9]

I don't think you will find any one right answer. This is one of those topics that people very in opinions from one extreme to the other.

A lot of people like to do several warm up and cool down cycles with limited throttle along with a thicker mix of oil in the gas.

Others will fill everything up, start it, check for leaks, then just ride as normal.

For me I tend to get anxious so I start it up let it warm up with quick blips of the throttle if it acts like it is loading up. Get it warmed up and do a easy low speed run to make sure everything still works as it should. Check for leaks and check the plug for color then ride as normal.

No mater how you do it, it could run great or have problems so it is up to you. It is your bike and your money so get a few more responses and see what you think is right.

[cornishwrecker220]

i would run the bike at 32.1 for the first tank or 2 of gas...start the bike & check for any oil/water leaks...dont let the bike idle for too long as you dont want to oil everything up...jump on & ride the bike like you would normally for the first few miles but dont be too gentle or too hard on the RPMs..use the gears but dont let the motor labour,dont let the motor get too hot if riding in the woods & check the gbox oil & water after the first hour for leaks or low levels, top up if need be & repeat after that,( you may notice a small drop in fluids after the rebuild run process thats normal)..it wont hurt to wind the power on slowly but dont keep it in the powerband for any great length of time..shift up...on the 2nd tank of gas repeat the above but increase RPMs if you like.

[Slick_Nick]

Heat cycles are bullshit. Yes, the piston and cylinder expand and contract, but most think that by heat cycling the engine they are in some way "heat treating" the parts. This is far from the case. Heat treating forged aluminum would require another 700 degrees or so.

If you've put everything together properly, there is no real need for a "break in" on a forged piston, nor would you increase your oil ratio. Why would you want to risk damage to a new piston by running the bike lean??

Let it warm up, then ride as normal.

[SS109]

K.I.S.S. all the way! My procedure. Pretty much do everything like if it already had some hours on it. In other words, mix fuel like normal, let warm up like normal, and ride it like normal including full throttle, lugging, whatever. The only things I do extra is after the first warm up is to go over all nuts and bolts to check for anything that has worked loose/I forgot to tighten (this goes for the whole bike!), check for leaks and top off coolant if needed, and change the trans fluid after the first ride. That's it! If it worked fine on my old, high strung Yamaha RD twins then it should be fine for a mildly tuned engine like the KDX.

[david]

K.I.S.S. all the way! My procedure. Pretty much do everything like if it already had some hours on it. In other words, mix fuel like normal, let warm up like normal, and ride it like normal including full throttle, lugging, whatever. The only things I do extra is after the first warm up is to go over all nuts and bolts to check for anything that has worked loose/I forgot to tighten (this goes for the whole bike!), check for leaks and top off coolant if needed, and change the trans fluid after the first ride. That's it! If it worked fine on my old, high strung Yamaha RD twins then it should be fine for a mildly tuned engine like the KDX.

X2

[BeanStalk]

Thanks all!

My 15-year-old son has been tracking the cylinder's progress from Langcourt to Knoxville on UPS.com like he used to track the progress of Santa Claus on Christmas Eve! Scheduled to arrive tomorrow... Carb and head are back from RB, bottom end is buttoned up and back in the bike. So unless we forgot to order something else, we should have it back together by the weekend.

I've been reflecting on how badly I'm spoiling my son - I'd guess I'm into this now for about $800? Amazing how things add up. But I'm tellin' ya - we are both learning a ton, together. He reads my posts, so I have to be careful what I say. But I think he is going to be very proud of his (our) bike when we get it put back together. And he's going to know how it's put together, and what makes a 2C engine go (Santa gave him a blown Briggs & Stratton lawnmower engine and a socket set when he was 8 - so he had the 4C figured out). And, most important I think - he's going to see that you don't just throw stuff away when it breaks, and buy a new one! That's big stuff for a 15 year old these days. It's different from when I was his age - 35 years ago!

Someone told me something a few years ago: My parents didn't spoil me, because they couldn't. It's hard today - there's no end to what kids want and parents seem to be able to buy them. We've held back on the electronics (no game boys, no X-Box, no wii, etc... Hell, we didn't get cable until a few years ago... Go outside and get dirty!). Even though we could have.

I may have to buy some knee braces now, so that I can keep riding with him. And I might start looking for a bike with one of those magic grey buttons on the bar? Or maybe another KDX - a LOT easier to kick over than my KLX300. This is good stuff!

So bottom line - I hope we get it put together right, and break it in right. But if not, we'll know how to tear it apart and do it again. Money, and especially time, well spent!

My 14 year old daughter has recovered from her broken collar bone (her last ride... we''ve got to stop breaking stuff!), so maybe we'll all be able to get out there this weekend! If I can figure out how to add pics (may need to lean on the kids for that) I'll share shots of the final product!