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No spark!

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First post to thumper talk, just hoping to get some extra brains on this one!

 

Ive got an ‘04 KTM200exc. Two major issues with machine so far.

 

1) Shift lever gets “stuck” in the bottom position when downshifting. When upshifting, lever springs to neutral position as designed. I’m thinking maybe it’s a return spring in the shift drum? I’ve pulled it apart before. Clutch basket and plates are in 100% working order.

 

2) I took my bike out around the neighborhood for a quick spin. Everything ran perfectly. Went to take it out a week later and it refuses to start. Pulled it apart to check plug. Completely fouled. Replaced with new plug, but still no spark. Ordered and replaced a new ignition coil, still no spark. I’ve since pulled it down to the flywheel, to check the and rewire the stator(work for an aerospace company so I can rewire for free.) 

2a) my questions regarding the spark.

1- other than the stator, ignition coil and plug, is there anything else in the ignition circuit that I need to do a one-over on? If the rewound stator doesn’t solve the issue I’m ordering a new CDI box.

2- I’ve never pulled the flywheel off. There are markings on the stator case and a punch on the flywheel. I assume those are top dead center markings? I don’t want to pull it apart and then fight forever finding TDC.

 

thanks for any help!

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Have you checked the plug wire itself? You can unscrew the plug boot off the wire and visually see if you're making contact with the center conductor in the wire.... not sure if the wire unscrews off the coil but ya could check that also

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The rotor (flywheel) is mounted on the crankshaft via a woodruff key so no adjustment. You adjust the backing plate on the stator so the stroke on it aligns with the right hand one on the case. SX models use the left hand stroke. Bob.

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Is the kill switch shorted perhaps? Normally pushing the kill switch amounts to shorting a wire from the CDI to ground.

 

If my knowledge serves me correctly, the kill switch being shorted would result in no spark even if everything else was functional.

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On 8/21/2019 at 1:40 PM, gdwrench said:

Have you checked the plug wire itself? You can unscrew the plug boot off the wire and visually see if you're making contact with the center conductor in the wire.... not sure if the wire unscrews off the coil but ya could check that also

Pulled the stator off and ran it to the shop. Lead engineer is 99% certain the generator on the stator is blown from max output being pushed for too long! We’re going to rewire the stator and put it all back together! Thanks for the help!

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On 8/21/2019 at 3:48 PM, 7Tktm said:

The rotor (flywheel) is mounted on the crankshaft via a woodruff key so no adjustment. You adjust the backing plate on the stator so the stroke on it aligns with the right hand one on the case. SX models use the left hand stroke. Bob.

Just to update, stator is officially blown and being rewired, so that should resolve my spark issue. My only other worry was aligning the flywheel, but your answer makes this so much easier than I figured it would be! Just one more question, I had to use quite a ton of leverage on my flywheel puller to remove the flywheel. Is there a good way to make sure the flywheel is placed back tight enough? Just want to make sure I get it set properly before cranking the bike back up!

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21 hours ago, freeride250r said:

Is the kill switch shorted perhaps? Normally pushing the kill switch amounts to shorting a wire from the CDI to ground.

 

If my knowledge serves me correctly, the kill switch being shorted would result in no spark even if everything else was functional.

Kill switch was one of the first things in circuit I tested! Sorry, I forgot to mention that I tested that. Turns out the stator is, in fact, blown. Thanks for the input!

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Usually breaks away easily  with the puller, maybe been overtightened . We use a flywheel holder which is basically  a set of adjustable vice grips (we call them mole grips) with a pin on each arm which you adjust to fit into the 2 indents on the flywheel (put a lot of hand pressure on it as they slip out of the indents easily) while someone else torques up the nut. Important to tighten it to the correct torque value.  Bob

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Usually breaks away easily  with the puller, maybe been overtightened . We use a flywheel holder which is basically  a set of adjustable vice grips (we call them mole grips) with a pin on each arm which you adjust to fit into the 2 indents on the flywheel (put a lot of hand pressure on it as they slip out of the indents easily) while someone else torques up the nut. Important to tighten it to the correct torque value.  Bob


Thanks Bob! We’re thinking about vamping the stator up quite a bit so I can run more than 30w. We run out of an aerospace engineering shop so have really fine gauge wire that can take a lot of stress(aircraft grade wire)

Was wondering if you’ve ever messed around with adding output to the stock stators? I’d love to get more output of the stator but the last thing I want to do is ruin the thing. The only piece in circuit that I can think of that might be affected by the added power is the aftermarket Reg/Rec I have on the bike for LED lights? It’s a high power output cyclops piece though so I assume it can take up to a very large amount of power?

Again, thanks for all your help!

Logan

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