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Discussion Starter · #1 ·
I have a 1999 Honda TRX450ES that only starts and idles when you let off the start button. If you pull the plug out and crank it it only sparks when you let off the starter. When running if you give it gas it dies. I have replaced the pulse generator, CDI box and checked battery voltage and connections. Has anybody else had a similar problem and what is next to check or do? Thanks in advance for any help.
 

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Sounds like you may have a bad ground somewhere. Welcome to the forums!
 

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I would have to agree with Sub...

Welcome to the site...
 

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Have you checked the ignition coil? If it's not a bad ground, it could be the ignition coil or the stator.
 

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Have you checked the ignition coil? If it's not a bad ground, it could be the ignition coil or the stator.
I didn't even think about the coil. But wouldn't the cut in speed of the stator be to high to have any effect? Just trying to learn something.
 

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Have you checked the ignition coil? If it's not a bad ground, it could be the ignition coil or the stator.
I didn't even think about the coil. But wouldn't the cut in speed of the stator be to high to have any effect? Just trying to learn something.
Maybe, but I've seen them do some weird things. My money's on the ignition coil, though.
 

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Have you checked the ignition coil? If it's not a bad ground, it could be the ignition coil or the stator.
I didn't even think about the coil. But wouldn't the cut in speed of the stator be to high to have any effect? Just trying to learn something.
Maybe, but I've seen them do some weird things. My money's on the ignition coil, though.
Yep since you mentioned it i'm with you. But you know a lot more about this stuff than I do. Remember I went to first grade twice!:icon_ cry:
 

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Discussion Starter · #8 ·
Thanks for more idea's. I will try to check out the coil next. Doe's the stator assist in the firing of the plug or just in the charging? I thought the pulse generator was the only thing inside the rear case that would affect the firing. But I don't know just asking?
 

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Discussion Starter · #9 ·
Ok just looked at a wiring diagram and I see that the green wire going to the coil goes to the frame ground. Checked it and it has good ground. The black wire with yellow tracer goes from the coil to the CDI box. Should this have some kind of voltage with the key on or while cranking? It's not really showing any voltage. I have tried a new CDI box and it does the same thing. Confused Again!!!
 

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Thanks for more idea's. I will try to check out the coil next. Doe's the stator assist in the firing of the plug or just in the charging? I thought the pulse generator was the only thing inside the rear case that would affect the firing. But I don't know just asking?
In addition to charging, the stator generates the power for the spark. The pulse generator is just a hall effect sensor that signals when to fire, but when it goes bad, it usually won't fire at all. I would check the ignition coil first.
 

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Agree^^^^^ checking the voltage at the coil is difficult sometimes it's much easier to OHM it out just connect one lead to ground and the oother to the black/yellow terminal you should see I think around .08 OHMs to .12 OHMs and then check between the sparkplug end and black/yellow for a readin I don't know what they are supposed to be check your service manual or Helmut may have some numbers for you. good luck.
 

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if it's not your coil..then i would say it's your stator..if your stator isn't working right..you won't generate enough voltedge to power the spark plug coil.
 

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Discussion Starter · #13 ·
Just installed a new coil and have the same problem. Any way to check the stator before I go purchasing it?
Thanks for all the help. When I finally do find the problem I will be sure to post what fixed it so maybe somebody else won't have to go through all this.
 

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Any way to check the stator before I go purchasing it?
Yeah, you can check the resistance of the stator with an ohmmeter, but I don't have a manual for the 450, so I don't know the specs for the stator. Maybe someone else will have the manual and be able to tell you.
 

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i don't have any spec's for that bike either...but..to answer your question..yes..you don't have to remove the stator to check it..just unplug the harness for it..with a ohm meter..you can check it that way....i bet your stator is bad...i know you said you replaced the c.d.i..buttttttt..did you replace it with the same year and make ?..they have to match perfectly !..or they won't work right.
 

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Discussion Starter · #16 ·
Got the manual online. Checked the stator and it appears to be shorted to ground. Shopping for a stator. Will keep you updated.
Thanks Again!
 

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Glad you found the problem.
 

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Discussion Starter · #18 ·
Still not fixed. Replacement stator did not fix it. Is it possible the voltage regulator could cause this? About the only think I haven't replaced.
 

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Now this trx450es is in my shop. I have checked grounds, new ignition switch, and still has problem. I remember in the mid 90's, Honda had the same problem with there trx 300 model whch required a new cdi box to fix. But a new cdi box did not fix this one. Someone must have run into this before. What can it be?
 

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did anyone check to see if thier diode was good ???..it's in the wire harness..at least most 300's have them.
 
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