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142 main, 40 idler, usually 1 1/2 turn out on the mixture screw, i forgot which position on the clip...

1997 kdx 220, last time it ran was perfect hot/cold/two kicks maximum to get it going. top end has about 50 hours on it.

the petcock started leaking, so I rebuilt the orings, then realized it was just the spring tension from the cover, not the seals. whatever, it's solid now.

kicked bike = nothing
surprised, kicked bike again = nothing
choke + a little throttle = bike starts and runs, but only with throttle input. it will not idle on it's own.

pulled jets, cleaned out crap from bad gas (ethanol), new plug, same symptoms:
bike only runs with input, or if it will idle, is very very slow.

air screw has no effect
idle screw has no effect

i'm scratching my head on this one.

help ?

air leak my friend. Check to make sure everything is sealed regardless if you have the airbox lid removed. I had my bike tossed from me and had the same problem. Went through everything but only finding that I had knocked the air boot from carb a bit. Couldn't really notice it but had the same probs. Give that a whirl and it explains why you have to give more fuel. Your getting more air now somehow. More air means you need more fuel or choke and throttle to run.

ICRage42 wrote:air leak my friend. Check to make sure everything is sealed regardless if you have the airbox lid removed. I had my bike tossed from me and had the same problem. Went through everything but only finding that I had knocked the air boot from carb a bit. Couldn't really notice it but had the same probs. Give that a whirl and it explains why you have to give more fuel. Your getting more air now somehow. More air means you need more fuel or choke and throttle to run.

thank you ! I'll check that tomorrow

update-

I soaked the carb in pinesol, cleaned jets meticulously, everything is spotless.
Double checked the intake runner rubber and the airbox horn. They fit well, no leaks.
Fresh gas 40:1, and it fired up first kick on choke, with a little help from the throttle grip.

Idle was still extremely low, so I turned the idle screw almost all the way in. The bike responds instantly to throttle inputs, idles, but very low (around 900-1100 rpm by ear) and goes "butter butter pop butter" instead of a nice smooth 'breeeee' it used to do.

Another symptom: it smokes heavier than normal, and smokes very heavily on deceleration. I didn't ride it, just revved it a little in the driveway once it was warm.

So, what does this sound like to the gurus ?

NOTE: i have a biiiiig fun ride coming up SOON that will put about 10-12 more hours on the bike. would your diagnosis prevent those 10-12 hours from happening ? please explain. thanks !

smoking on deceleration means you have a bad crankshaft seal on the right side

Yep, I was going to asking if your transmission fluid has been dropping.

Jaguar wrote:smoking on deceleration means you have a bad crankshaft seal on the right side

thanks you.

looks like I need to split thing and fix her up.

Tedh98 wrote:Yep, I was going to asking if your transmission fluid has been dropping.

I had not noticed it dropping before today when I checked the level. I changed it one ride ago, to the top line, and today was at the bottom line.

good observation, and tip. I really appreciate the offers of knowledge from you guys.

Good news / bad news time.


Good:
Flywheel puller finally arrived.
No seized nuts/bolts around the cylinder (pbblaster soak for a week helps)
No issues with the cylinder
No issues with the pist.... uh oh hold on a second
No issues with the flywheel
No issues with the kips assembly besides crusty
No issues with the conrod
No issues with the crank (yet, we'll see how i screw it up!)

Bad news:
PIston skirt is cracked, about 25% is still holding on. :(
I thought I remembered the PO telling me it was a wiseco, but I don't really remember.


and the inside:


time to hit the ebay for a nice piston. do we still like wiseco ?


Oh, piston measurements. Someone requested these a few days ago, but I couldn't get anything done until now:

Piston:

Left to Right Front to Rear
(top of comp ring to bottom)

2.700 2.698
2.705 2.705
2.709 2.708



Cylinder:

Left to right Front to Rear
(top of wipe to bottom between ports as possible)

2.720 2.720
2.719 2.720
2.718 2.719

Weisco or Wossner pistons are nice.

You did get lucky the skirt didn't completely drop on you

I don't mean to bash on you but for others that might read this post.....THIS is why you ALWAYS check the piston in a newly purchased 220. It doesn't matter what the PO tells you, you GOTTO confirm.

6 Riders wrote:Weisco or Wossner pistons are nice.

You did get lucky the skirt didn't completely drop on you

I don't mean to bash on you but for others that might read this post.....THIS is why you ALWAYS check the piston in a newly purchased 220. It doesn't matter what the PO tells you, you GOTTO confirm.

it's not considered bashing, it's "i told ya so", and it's fine/understandable :)

mechanicals have known fault points, and i dodge a bullet, but just barely :)

you lucky duck!

I can't find a reference for piston sizes, is there one for our bike or do we just call with measurements?

the cylinder is 69.088mm according to those measurements. 69mm is stock piston size for 220. If it was me and the nikaseal is good, fluff the walls out with some scotchbrite and slam a new piston in there. Then ride wheelies.

newbbewb wrote:the cylinder is 69.088mm according to those measurements. 69mm is stock piston size for 220. If it was me and the nikaseal is good, fluff the walls out with some scotchbrite and slam a new piston in there. Then ride wheelies.

ordered a stock size wiseco last night .
. hopefully it's here this weekend and I'm riding next.

THANK YOU!

some progress:









this afternoon i'll pull the old bearings off the crank (i hope!) and install new seals/bearings, then assemble.

if i don't screw everything up test ride is wednesday.

then a full weekend of playing on my recently tagged kdx

I've only had my bike for a couple years and never did a top end but when I looked at the piston through the exhaust port it looked brand new and clean as a whistle, machining marks and all. Also the piston that came out of it looked clean around the skirt, not the top. So my question is if the piston in the pics is normal usage or has it been rattling around in the cylinder.

Silverfox wrote:I've only had my bike for a couple years and never did a top end but when I looked at the piston through the exhaust port it looked brand new and clean as a whistle, machining marks and all. Also the piston that came out of it looked clean around the skirt, not the top. So my question is if the piston in the pics is normal usage or has it been rattling around in the cylinder.

OEM 220 pistons are known to give way at the skirt. That is why you hear/read "CHANGE that piston".

My 220 stock piston looks great as well. It garnishes my office file cabinet nicely.

Silverfox wrote:I've only had my bike for a couple years and never did a top end but when I looked at the piston through the exhaust port it looked brand new and clean as a whistle, machining marks and all. Also the piston that came out of it looked clean around the skirt, not the top. So my question is if the piston in the pics is normal usage or has it been rattling around in the cylinder.

the cracks allowed the piston to expand, wear accelerated, and the resulting aluminum slurry killed the crank seals, and partially the crank bearings too.

that should be enough reason for anyone to want to change stock piston.

but since you asked, yes, mine had been talking around. not enough to cause audible rattling, but enough to accelerate wear. I left the stock piston on the connecting rod while I'm doing everything to protect the rod. once in all done the bottom end is assembled, I'll install the new wiseco.

everything is soaking in pbblaster and transmission fluid to break up the carbon on the kips for tonight.

I would suggest taking the advice of the folks here, if for no other reason than to prevent a bottom end service and it's expense. $$$