o.s. o.b. piston & sleeve

[k&b guy]

broke in w/ 60% , no water restriction , 2.5 turns out on h.s. needle per inst. very rich. running cold. after 6 tanks , started to lean it out. ran great at 1.5 turns out. still too cold. soldered hole in outlet nipple & drilled it out to .060. still hold head after 5 wot laps. disconnected water line & ran 3 wot laps. water sizzled on head , & melted solder out of nipple. after cooling down , still tight at t.d.c. removed head & button. no binding at all at tdc. did i wear out piston due to overly rich setting & not enough heat ? need some help !!! CARTER

 

[Richard Dahlheimer]

broke in w/ 60% , no water restriction , 2.5 turns out on h.s. needle per inst. very rich. running cold. after 6 tanks , started to lean it out. ran great at 1.5 turns out. still too cold. soldered hole in outlet nipple & drilled it out to .060. still hold head after 5 wot laps. disconnected water line & ran 3 wot laps. water sizzled on head , & melted solder out of nipple. after cooling down , still tight at t.d.c. removed head & button. no binding at all at tdc. did i wear out piston due to overly rich setting & not enough heat ? need some help !!! CARTER

Carter, if i am understanding your post correctly, you still had pinch at TDC, after motor cooled down. Maybe, when you removed head and button, the sleeve is lifting out of the crankcase as you turn motor uo to TDC. If the sleeve is sliding up out of the case, you will loose the pinch. Hope this helps. Richard D

 

[k&b guy]

richard , the sleeve is not moving. it seems like the button is squeezing in the i.d. of the sleeve.

 

[Jerry Wyss]

When you removed the water altogether did you open the needle from the 1.5 turn setting?

It's a simple trade off and makes good sense,, instead of trying to heat the motor up with a lean

setting,,simply heat the motor up by denying it water and leave the needle where its at (2.5 turns)

and work the needle in from there.

If your going to run it rich (in cold weather) from the start, take the water off from the start, not

after you already leaned it out.

Actually the first thing I should have stated is that the "outlet end" of the water pickup tube is

already well below .060",, it's actually .040"

For people that are really paranoid about cutting the water altogether, I offer a short piece of

fuel tube (silicone) on the head water exit with a 1/4" piece of brass tube in there pinched

to near nuthin' on the exit, barely perceptible.

Running it rich (cooling with fuel) while building heat by denying water gives you more power

and more lubrication, YOU CAN'T LOSE.

Also If you haven't removed the shim yet, when you take it out you'l have instant pinch.

If the shim was out when you did all this, all is not lost, the piston can have the cutting wheel

applied to it and get your pinch back that way.

 

[Richard Dahlheimer]

When you removed the water altogether did you open the needle from the 1.5 turn setting?
It's a simple trade off and makes good sense,, instead of trying to heat the motor up with a lean

setting,,simply heat the motor up by denying it water and leave the needle where its at (2.5 turns)

and work the needle in from there.

If your going to run it rich (in cold weather) from the start, take the water off from the start, not

after you already leaned it out.

Actually the first thing I should have stated is that the "outlet end" of the water pickup tube is

already well below .060",, it's actually .040"

For people that are really paranoid about cutting the water altogether, I offer a short piece of

fuel tube (silicone) on the head water exit with a 1/4" piece of brass tube in there pinched

to near nuthin' on the exit, barely perceptible.

Running it rich (or cooling with fuel) gives you more power and more lubrication, YOU CAN'T LOSE.

Carter, what does the top of the piston look like? Is it pitted and lite colored? How does the head button look? How was the plug after the last run? If your piston top and head button look ok, i would reasemble the motor, and install a glow plug. Turn motor over by hand and see if you have any compression. If no compression, you will need a new piston and sleeve. Follow JWs advice above on the cooling and needle setting. Richard D

 

[k&b guy]

the top of piston looks good. button is discolored where it sat over bore. glow plug was mangled after run w/o water. installed new one , hooked up water , & ran more laps. i see what jerry is saying. i restricted the outlet to .050 when the inlet was already .040. duh. right now i have a slight pinch w/ head on. looser than hell w/ button off. how hot should head be ? CARTER

 

[k&b guy]

shim was removed after breakin , before restricting water. so if i understand this right , you need water restriction during break in(2.5turns) and as you lean on it , open up the water res. as you go. yes ? CARTER

 

[Jerry Wyss]

Carter, I shoot mine with a heat gun quick as we can after pullin' it outa the water (takes two of us)

and the highest I've shot was 300,, but a good spot is 225 to 250. Now 300 is too high cause the

operating temp out on the water @ full throttle was close to twice that,, but the boat went about 4 laps

before it took off due to being extremely rich (this was not an OS)

In this kinda weather and low water temp, none of us (group I run with) can get our hyperf O/B 21's

to go with water flowing thru. We pull the water off (with the water head on) and cool them with the fuel.

Even in the summer ( I don't run water) I use the water head (without water) to break-in a new P&S or a

new engine. Thats with the rich setting, so the engine will swell to operating temp to break-in, better there

than cold.

Oh, that 300 degree run, turned a McCoy MC59 plug body "blue" from the heat, Rocket run! without damage

to the engine cause I was running it richer than the engine ever would be normally.

JW

 

[Jerry Wyss]

shim was removed after breakin , before restricting water. so if i understand this right , you need water restriction during break in(2.5turns) and as you lean on it , open up the water res. as you go. yes ? CARTER

You live Calif I see, don't matter really, the heat you can make by leaning can also be made by restricting

the water,, which allows more fuel and lube to be used to get it to that critical temp where it runs best.

Again, this allows more fuel to be used,,,,,

{Also, taking the shim out increase's the compression which generates heat by itself}

 

[k&b guy]

jerry- how do you recommend i break in the new p/s. 2.5 & no water ? check temp. after 1 or 2 laps ? if it`s o.k. leave it like that after breakin , or lean on it a little bit & open up the water a little bit ? it sounds like a balancing act. CARTER P.S. I LIVE IN THE MOUNTAINS(2500FT.) CENT. CAL. COLDER THAN CRAP!

 

[k&b guy]

AMam i correct in assuming that the rich setting (cool) and cold water kept the top of the sleeve from expanding, & wore down the o.d. of the piston ?

 

[Jerry Wyss]

jerry- how do you recommend i break in the new p/s. 2.5 & no water ? check temp. after 1 or 2 laps ? if it`s o.k. leave it like that after breakin , or lean on it a little bit & open up the water a little bit ? it sounds like a balancing act. CARTER P.S. I LIVE IN THE MOUNTAINS(2500FT.) CENT. CAL. COLDER THAN CRAP!

lol,, I guess it can get cold down there too, hahaha

uh, well you can run them so rich (without water) that they will barely run,, and run cold too,, say 3 turns out or more.

Not all carb settings are the same, even with that 20J carb (of which I use on several motors),but it's a much better spot

to start from and work in. You can work the needle in fairly quickly, after a two lap run,, move it in several clicks to

find a more reasonable running and get to where the head feels fairly warm,, break it in there.

The XM sleeve deserves at least 3 to 4 eight ounce tanks before you take it above that "fairly warm" area,, it should be

more than enough for you by the time you get it to a 3 second grab of the head hot.

Cold water is always trying to draw heat outa that motor, splashing the muffler and the lower unit, so things will dramtically

change with the needle when you take it to another pond or even a different day,, so richen it up again when you take it

out next. Once the weather gets better, put the water back on but squeeze it down to bare minimum.

2 or 3 second hot should be good enough, Remember, a "second" is longer than you think, it gets shortened up quickly

when your grabbing something hot! :lol:

 

[Jerry Wyss]

AMam i correct in assuming that the rich setting (cool) and cold water kept the top of the sleeve from expanding, & wore down the o.d. of the piston ?

Very possible,, but "the blowing out of the solder" bothers me,, it could have just been soldering a chromed/brass

nipple just didn't stick and out it went. (but the plug did get mangled, unusual for a cold motor)

But, Yes, having things cold like the P&S can take the pinch out in short order, it's just not good for'em.

I did it to a few K&B's before I knew better,,,

 

[k&b guy]

jerry- that`s the kind of info i was looking for. i found the solder in a puddle at the bottom of the "water jacket". this really pis--- me off. i`ve had 2 k&b`s over the years, & i just leaned themout from the get go. when i`d hit the right spot , after 3/4 laps it sounded like you just downshifted.right on the edge of too lean. they would sing. never worried about water restriction. the o.s. never did sing even before i played w/ the water!!! do you think the compression was already going before the water fiasco ? CARTER

 

[Richard Dahlheimer]

AMam i correct in assuming that the rich setting (cool) and cold water kept the top of the sleeve from expanding, & wore down the o.d. of the piston ?

Very possible,, but "the blowing out of the solder" bothers me,, it could have just been soldering a chromed/brass

nipple just didn't stick and out it went. (but the plug did get mangled, unusual for a cold motor)

But, Yes, having things cold like the P&S can take the pinch out in short order, it's just not good for'em.

I did it to a few K&B's before I knew better,,,

Carter, if you dont have any experience working on motors, it would be a good idea to have your motor checked by some one. It could save you some money and frustration. Good Luck, Richard D

 

[k&b guy]

inst. say to break in @ w.o.t. that`s what i did. correct method ? THANKS FOR ALL YOUR HELP , JERRY !! CARTER.

 

[Jerry Wyss]

jerry- that`s the kind of info i was looking for. i found the solder in a puddle at the bottom of the "water jacket". this really pis--- me off. i`ve had 2 k&b`s over the years, & i just leaned themout from the get go. when i`d hit the right spot , after 3/4 laps it sounded like you just downshifted.right on the edge of too lean. they would sing. never worried about water restriction. the o.s. never did sing even before i played w/ the water!!! do you think the compression was already going before the water fiasco ? CARTER

Like I said, very possible :huh:

But I can't know what went on way down there,, all I can give you is the method I would use for running an engine

in the cold kind of conditions we are in this time of year. An aircooled engine would be the same, I wouldn't even start

it without removing the airhead and just bolting the headbutton down.

It's just bad conditions to run these things unless your aware of what to do, warning signs will let you know but you have

to be able to recognise them quickly before they do damage.

An XM will run extremely strong with full water running thru them, don't get me wrong, just not in very cold air & water,

your losing precious heat at both ends of the motor. And don't ignore the trading of needle heat for reduced water heat

cause it will always result in more fuel going thru the engine which equals more power.

 

[Jerry Wyss]

inst. say to break in @ w.o.t. that`s what i did. correct method ? THANKS FOR ALL YOUR HELP , JERRY !! CARTER.

Yeah, but you will have to throttle them sometimes,, you know, your gonna break things sometimes doin' this,

thats one of the ways you learn what Not to do,, it happens to allot of us.

sorry, I got tire'd zzzzzzzzzzzzzzzzz

 

[k&b guy]

i removed the wrist pin ret. clips & pin. practiced reinstalling on old piston to find best way w/o scratching new piston . when clips are squeezed , they do not retain origonal shape. could heat have taken tension out of them ? do you guys always replace them on a rebuild ? carter

 

[Jerry Wyss]

I don't use the clips again and wouldn't advise otherwise and they don't normally bend easy and stay

that way.