Did I break it in right?

xr400forever · Nov 4, 2002

So I just finished a top-end job on my 2000 220. I used a stock piston and all new parts on the top end(rings, wrist pin, small end bearing, gaskets, wrist pin clips). So far I have done the following for break-in:

Idle 5 minutes--complete overnight cool-off
Ride 15 minutes 1/2 throttle or less, off and on the gas---25 min. cooling
Ride 20 minutes 1/2 throttle or less -- 25 minutes cooling
Ride 20 minutes 3/4 throttle or less --overnight cooling.

I am concerned the I might not have let it cool off enough on the 25 minute cool-offs. The engine was still warm to the touch when I started after the 25 min. Air temp. was about 50 degrees at the time. Can anyone comment on the suitability of what I have done so far and what I should do for the remainder of the break-in, or maybe I am done??? Thanks in advance for your replies!

canyncarvr · Nov 4, 2002

Don't sweat it TOO much. Time to go riding!! Maybe keep the WOT screaming down to a minimum for a short while maybe.

Regarding the first step..the idle 5 minutes part, note the following:

From EG's website:

When you initially start the engine after a rebuild, manipulate the choke to keep the engine rpm relatively low. Once the engine is warm enough to take it off choke, drive the vehicle around on flat hard ground. Keep it under 2/3 throttle for the first 30 minutes. Two common myths for proper engine break-in are; 1) Set the engine at a fast idle, stationary on a stand. 2) Add extra pre-mix oil to the fuel. When the engine is on a stand it doesn't have any air passing through the radiator and it is in danger of running too hot. When you add extra oil to the fuel you are effectively leaning the carb jetting. This can make the engine run hotter and seize

Have fun!!

KelvinKDX · Nov 5, 2002

You used a stock piston on a 220 rebuild? I thought that 220 owners were advised away from the stock piston.

Or is this just a myth?

canyncarvr · Nov 5, 2002

kelvin:
Not a myth. A fact. The oem 220 piston is a known weak spot. Usually (says CDave) doesn't cause a problem unless the bike is modified considerably/ridden hard.

xr didn't want to use a wiseco cuz of ANOTHER myth..that wisecos are terrible for their own (mythical) reasons.

Never did hear, xr, if you got a Pro-X piston of the correct alpha designation, or stuck in an over-the-counter kawi piston. And did THAT match your motor's designation?

No, I don't have a 220. What CDave says is gospel for one thing...and I've read posts from 220 users that remarked on THEIR failed 220 pistons.

For xr's application, he'll be just fine....probably.

xr400forever · Nov 5, 2002

canyncarvr: I ended up with an oem piston, apparently Pro-X does not make one for a 220. My cylinder was an "A" size but I don't think the stock pistons had fractional oversizes available.
I had heard 2 things that scared me off of Wiseco's (forged pistons)
1. A local motorcycle based machinist told me they are more prone to siezure, due to greater expansion.
2. A high performance shop in California (JP Innovations, I think) claimed that a forged piston would last longer.

SOMETHING VERY INTERESTING: My shop ordered a Wiseco piston for by mistake, it measued 69.00mm. The new stock piston I put in the bike measured 68.91 mm. my old piston was 68.84mm.I measured the cylinder bore at 69.01-69.02(smaller than the manual claims it should be-maybe just my measuring tools?) I am led to belive that I would not have had sufficient clearance in my case. Another thing I found interesting was how much bigger the Wiseco was. Given that it was bigger and that forged expand more I almost think I would have been a candidate for a siezure if I had put it in. I any case I don't have to worry about finding an fractionally oversized piston down the road as the bore wears, since the Wiseco is significantly (I think?) bigger.

I don't know maybe I am worried about nothing. has anyone even heard of Wiseco's siezing on 220's

canyncarvr · Nov 5, 2002

From EG: (bold my emphasis)

Before attempting to order a Pro-X piston, you must measure the cylinders bore at the smallest point and allow .002 inches clearance between the piston and cylinder.

Your measurements give you about .0035 the way I figger. Is that what it measured? The piston should have the alpha designation stamped on the crown. No, you can't designate what 'oversize' you get. The dealer told me they are 'usually' 'B'..but not always. The one I got from the local kawi dealer for my 200 was stamped 'B'.

The difference between the alpha markings is supposed to be .01mm (.0004"). Not a killer if you don't match the desinations right on.

With the wiseco @ 69mm..that's a problem, as that's the BORE size of the 220! Wiseco lists the bore as such in their pdf catalog.

Anyway, you're right about the PRO-X not being available for the 220. That's new, I think. I notice the webpage is completely different than the last time I looked at it. They do list all the available sizes for the 200, but only the 'b' for the 220.

A btw..from what I've read, it's not how MUCH the wiseco expands quite, but the RATE of expansion of a wiseco. In any case, the fit of it is important. Sounds like in your case you caught a problem before it happened!

Looks like your original piston was pretty darn loose!

Any evidence of nicosel damage?

At least you're measuring 'stuff'. I'm surprised at how often I hear riders NOT doing that, cuz 'it's supposed to fit.' THAT'S trouble waiting to happen......

Again, congratulations.

Enjoy your 'new' motor! (yeah...I know it's an 'engine';) )

RJ-KDX · Nov 8, 2002

Hey carvr,

Before attempting to order a Pro-X piston, you must measure the cylinders bore at the smallest point and allow .002 inches clearance between the piston and cylinder.

Is that measurement .002" per side or total, being .001" per side. Just wondering, haven't done my top end yet.

Thanks. :yeehaw: :eek: :yeehaw:

Did I break it in right?

xr400forever

canyncarvr

KelvinKDX

canyncarvr

xr400forever

canyncarvr

RJ-KDX

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