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Author Topic: kx 100 problem  (Read 5769 times)

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daniboy

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kx 100 problem
« on: June 02, 2007, 01:55:04 AM »
me and my mate were out on the kx 100 the other day and the back wheel just locked up and cut out. now it wont start at all even though we changed the pistons that we thought was the problem. please help as it might be something else before it goes for a full engine rebuild????
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Offline alan

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Re: kx 100 problem
« Reply #1 on: June 02, 2007, 02:58:00 AM »
Do you have spark, could be nothing more than bad plug or CDI went bad! Always check that first!
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daniboy

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Re: kx 100 problem
« Reply #2 on: June 02, 2007, 04:04:23 AM »
sparks brilliant but what could the cdi boox have to do with it???
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Offline alan

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Re: kx 100 problem
« Reply #3 on: June 02, 2007, 04:13:52 AM »
Quote from: daniboy on June 02, 2007, 04:04:23 AM
sparks brilliant but what could the cdi boox have to do with it???
Only if you had no spark.......
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       04- 700V - 01- KX500
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Offline alan

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Re: kx 100 problem
« Reply #4 on: June 02, 2007, 04:14:40 AM »
What is the Compression?
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daniboy

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Re: kx 100 problem
« Reply #5 on: June 02, 2007, 07:24:22 AM »
quote author=alan link=topic=3312.msg23949#msg23949 date=1180800880]
What is the Compression?
[/quote]

the compression is alot weaker

and it backfires every 3/4 kicks
« Last Edit: June 04, 2007, 09:02:35 AM by daniboy »
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Offline hughes

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Re: kx 100 problem
« Reply #6 on: June 05, 2007, 03:18:50 AM »
Is the rear wheel still locked up? Or was that due to the engine stalling out? Sheared flywheel key? Do you have a service manual? The manual will give you specs for testing your ignition system. What was the condition of the cylinder and piston? You said you replaced the piston and compression is weaker.
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daniboy

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Re: kx 100 problem
« Reply #7 on: June 05, 2007, 09:38:32 AM »
no the rear wheel is ok now. the pistons we took out of the bike looked like they were welded in because they were really stuck in the piston!! no he didnt get a manual but can get one.
yeah the compression is not like it was and it backfires alot.
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Offline hughes

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Re: kx 100 problem
« Reply #8 on: June 05, 2007, 09:48:53 AM »
Quote from: daniboy on June 05, 2007, 09:38:32 AM
no the rear wheel is ok now. the pistons we took out of the bike looked like they were welded in because they were really stuck in the piston!! no he didnt get a manual but can get one.
yeah the compression is not like it was and it backfires alot.

If the piston looked like it was welded in place then your plating in your cylinder might need repaired. If the engine came to quick stop from a high rpm it can shear the flywheel key might be why it is backfiring, but from what you said about the piston you have other issues to be concerned with. Photo's of the piston?? Photo's of the cylinder??
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Offline Hillclimb#42

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Re: kx 100 problem
« Reply #9 on: June 05, 2007, 09:50:16 AM »
 How did you break the motor in? I put a light coat of two-stroke oil on piston to put it in the cylinder. Then I start and warm the bike up 4-5 times before riding it. Then on the first ride, I baby it around for about 15-30 minutes, let it cool all the way. Then I give it hell everytime. I just brought that up because I have melted em down before, during break-in. The throttle was adjusted out too far. It started, went crazy for about 20 seconds, then died. It was crazy, man. I have two kill-switches, didn't stop it. Pulled the plug-wire, didn't stop it. Pulled the gas line, that stopped it eventually, but like I said was melted down and pricey mistake.
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daniboy

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Re: kx 100 problem
« Reply #10 on: June 05, 2007, 09:57:50 AM »
If the piston looked like it was welded in place then your plating in your cylinder might need repaired. If the engine came to quick stop from a high rpm it can shear the flywheel key might be why it is backfiring, but from what you said about the piston you have other issues to be concerned with. Photo's of the piston?? Photo's of the cylinder??
[/quote]

4th gear in powerband and then just packed up with us coming to a skiding stop. ill try and get photo's of the piston on tomorrow night.

so where can i find the flywheel key? obviously near the flywheel but what does it look like, iv'e never heard of it before.
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Offline Hillclimb#42

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Re: kx 100 problem
« Reply #11 on: June 05, 2007, 01:26:31 PM »
 Flywheel key is behind cover on shifter side, its the square shouldered little steel piece that holds the flywheel onto the crank. If it spun you may have damage to the crank. You'll know when you open up the cover, because there'll be little chunks of it in there.
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daniboy

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Re: kx 100 problem
« Reply #12 on: June 05, 2007, 11:49:12 PM »
thanks the bike will proberly be coming to bits at the weekend so ill check all of these things again. help is much appreciated guys :-D
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