'00 KX100-Did I blow my top end?!? Help!

[Blinkme7182]

Hi, I have a 00 KX100. A couple of days ago, I had it opened up in 6th gear for about 30 seconds or so, and then I decellerated pretty quickly into first gear, but I revved the bike in each gear as to prevent it from stalling, but it stalled anyway. It wouldn't start back on, it wouldn't jump start, and it felt like it wasn't getting any spark. So anyway, I changed the oil, gas, coolant, cleaned the air filter, and put a brand new plug in, and it still wouldn't start or jump start, and then put another plug in, and it stil wouldn't start.The funny thing about the plug that I took out that was in was that a) it had some black oil near the washer on the plug threads and near the electrode, and there was a chip/gouge on the electrode area, which looks like the piston was actually hitting the plug. So the plug I replaced it with, after I had only kicked the bike over 10-15 times had the same gouge on the electrode area that the original plug did. When I was trying to start it, it wasn't getting the slightest bit for spark, and like once or twice when I was kicking it over out of 15 times, it made this strange sound within the engine, but it was so quick, I couldn't distinguish it. The top end on the bike has never been replaced, and it feels pretty easy to kick the bike's kick starter, like there isn't that much compression left...My question a) what do you think the problem is and b) why would my bike all of a sudden stall like this and have problems, and if it did blow the top end, why would stalling it like this blow the top end? My friend thinks the top end is gone. Anyway, my dad just left for a 3 week trip, and he is very mechanically inclined, unlike me, so he won't be able to work on it, and I'd rather not waste money having a "diagnosis" done on my bike, so what are your opinions? Please help me asap, ...I'm missing peak foliage season in New England because of this. Thanks in advance,
Marc:think

 

[spanky250]

First, the piston in a two-stroke can't hit the plug. The combustion chamber is too deep, the piston would hit the squish band cut into the perimeter of the head.

For an engine to run, you need air, fuel, compression, and spark. Check each of these things one by one, and you will find the problem. I suppose it is possible that you burned a hole in the top of the piston, but it's not real likely.
Check all the things that I told you, then get back to us with what you have found, and we'll see what we can come up with.

 

[KawieKX125]

No resistance on the kickstarter, sounds bad. I think while it was WFO, you must have had detonation and burned up the piston. Then, the slag around the hole is hitting the plug. Just a thought. Personally, I would tear the top end apart to check it out.

 

[spanky250]

Take the plug out, and put your finger over the plug hole. Hold the throttle wide open, and have a friend push the kick starter through it's stroke. If the pressure pops your finger off, then you don't have a hole in the piston. If there is no pressure, or it is very weak, it's time to tear into the top-end.

 

[Blinkme7182]

Okay, thanks for the info so far...I know air and fuel aren't a problem, but how would I check for spark (other than that I know the spark plugs I'm using are new,) and what else should I do to check for compression besides put my finger over the spark plug hole and see if it pops off when kicked over...if it doesn't then does that mean I need a new top end, or...?

 

[Buzz Bomb]

Just stick your hand over the hole, and kick the bike over. That's the easiest way. To check for spark, stick the plug on the cylinder head, and kick it to check for spark. I think your top end is worn, and it needs to be changed.

 

[spanky250]

Originally posted by Blinkme7182
what else should I do to check for compression besides put my finger over the spark plug hole and see if it pops off when kicked over...if it doesn't then does that mean I need a new top end, or...?

All you are doing with the finger test is checking to see if there is any compression at all, eliminating the possibility of a holed piston or broken ring. A proper compression test requires a compression tester. For your purpose here, which is to see if you blew the top-end, blowing your finger off the plug hole is a sufficient test to determine that there wasn't a catastrophic melt down. Just don't stick your finger inside the plug hole, if there really is some slag sticking up from the piston, you might get it jabbed into your finger.:eek:

 

[ButtonFly]

In case you were going to try it, don't even think about sticking your tongue in it. It's too bad some kid is getting dangerous advice... So you have a new plug, and you have gas in the tank right? As for compression, try the finger test. Taking your top end apart is not that hard, but you might want to wait for your dad. Have you tried bumpstarting the bike? One of my riding buddies (dirtygirly) has a KX100, and occasionally I bumpstart it for her, especially if it is cold. Good luck, and post some more info.

 

[Blinkme7182]

okay...

I just did the "putting your finger over the spark plug-hole" test, and it had enough pressure to pop my finger off, so I guess the bike just isn't getting spark. I put the electrode end of the spark plug horizontally right near/in the center of the spark plug hole in the cylinder head to see if it was getting any spark, and I couln't see any...is this how I check for spark? What could be the problem? Possibly clogged fuel line? My carburator and the hoses all are fine, non have come disconnected, etc...maybe I should drain all the gas and replace it with fresh, really well mixed gas? When I had taken it out the day it broke down, it was the first time it had been started/ridden in a week, and I had it up to 6th gear pinned after about 10 minutes of letting it run/warm up...let me know what ya think

 

[KawieKX125]

Try a new spark plug. I have seen odd situations like this where a bike iwll not start, and it even has spark. But, when I new spark plug is installed, it fires right up. Try it.

 

[Danny8785]

If your bike is sparkless, there is a few things you should check right off the bat. Like the spark plug cap, it could very well be loose, wet, or so dirty it is not making a connection. You should also visually inspect the kill switch wire for cuts or slits that could be allowing the wire/wires to ground out on the frame. If these simple things do not work, clean all the electrical connections on the bike. If that does not work, well, i guess you will have to wait for the dad.

P.S. To make sure it has no spark you should invite a freind over, stick a spark plug in the cap, and ask him to hold the tip of the plug while you kick it. You will find out very fast and acurately buy the loud screem and/or the fist in your mouth :p If there is no screem then, well, there is no spark.

P.P.S. You can do this test without a freind, but if i were you i would kick very, very slowly, and even if you do use the stupid buddy meathod, i would use my hand to push down the starter slowly. It will amaze you how much juice runs through those little wires. If you do not feel a bolt of electricity, then there is no spark.

 

[DINGUS]

?!?!

Damn Danny8785, I was just joking around with my post (that was removed), but you sound serious about the "check the spark with your body parts" method...But if you are going to do it, don't involve your friend, even if he is stupid enough...I think since my post was removed, *somebody thought this kid was actually going to try it...If thats the case he needs to leave the whole thing to Dad and grow up before he turns wrenches. (This post may not make any sense because Danny8785's post is probably laying in the trash can besides my first one...Sorry for trying to be funny, If you didn't think my first post was funny, see *)

 

[Blinkme7182]

Kawiekx125---The spark plug in it right now is BRAND NEW...so what else should I try to find out why it isn't getting spark?

 

[Blinkme7182]

P.S......

How should I clean the spark plug cap???? :think

 

[Redbird]

You may have a shorted out kill switch. Follow the wires on the kill switch down and there should be a place to disconnect them. You may have to remove the fuel tank, depends on were the connections are. After that check to see if you have a spark. If this doesnt work, try another new plug. I have had new plugs out of the box that would not work.

 

[baxterj787]

<Possibly clogged fuel line? My carburator and the hoses all are fine, non have come disconnected, etc...maybe I should drain all the gas and replace it with fresh, really well mixed gas? When I had taken it out the day it broke down, it was the first time it had been started/ridden in a week, and I had it up to 6th gear pinned after about 10 minutes of letting it run/warm up...let me know what ya think >

If you have no spark, then changing fuel /carb settings will not help. Also, your warm-up time (10 minutes) is plenty.

I have had a stator or two fail in the same way you described. How does the generator look? Remove the left engine cover and check for lots of rust or water. The cover is easy to remove (maybe 5 or 6 bolts) and is not supposed to have any fluids inside. If you remove the cover and see rust, you have gone a long way toward finding your problem.