KX Riders
Maintenance & Technical => KX500 Original => Topic started by: BrantSFGDS on April 29, 2014, 11:58:58 AM
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Greetings all! New member from KY here. So, let me bring everyone up to speed on my new "project". An old friend recently gave me an 87 KX500 as payment for getting his Bobcat running. The last time he rode the bike was 4 years ago at which point it ran great and the engine was fresh. He was involved in a serious accident which led to the bike being stored until 2 weeks ago. I brought the bike home and started all the normal maintenance along with rebuilding the carb. So, I got everything ready to go and didn't have any spark. I tested the electronics by the manual and found the ignition coil was toast. I scrounged up a good coil and now I have spark. At this point, the bike should run, or, at least, pop, fart, backfire or something. Nada, nothing! I can't come up with any mechanical reason why this bike shouldn't run. Compression is good, no blowback through the reeds and no obvious air leaks. Here's what I need to know, since I'm not a CDI guru; will a bad CDI box fire the coil, but at the wrong time? I ask because the spark I'm getting doesn't look normal to me. I'm a mechanic, just not a CDI guy, and everything I've ever spark tested before has a single spark across the plug at the appropriate time. This thing looks like a taser across the plug. I'm talking about grounding the plug on the head and pushing the kicker through by hand. Does this sound normal or do I need to start looking for a CDI box? Thoughts?
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This thing looks like a taser across the plug. I'm talking about grounding the plug on the head and pushing the kicker through by hand. Does this sound normal or do I need to start looking for a CDI box? Thoughts?
1st, welcome to the site!
I'm not totally sure I'm following completely right....but I had a similar experience with a 250, and it ended up being a cracked plug cap.
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Hey Brant, welcome!! Try reading "having electrical problems on your K5?" By sandblaster. That article had me up and running in no time!! Listen to these guys most everyone knows their sh!t and I've gotten all the help n info from this forum
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It may be a bit simplistic for you but it wouldn't hurt to review it:
http://www.oem-cycle.com/forum/viewtopic.php?f=40&t=163 (http://www.oem-cycle.com/forum/viewtopic.php?f=40&t=163)
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Thanks for the welcome guys! Sandblaster, I read the entire thread and found it to be very informative. I'm still at a standstill though because I don't know what to check next since I actually have spark. My first instinct is to look for something else since I have spark, but something doesn't look right about it. I checked the timing on the stator and it's fine. There is a procedure in my manual for how to test the CDI box. I had to go buy the required resistors and I hope to give it a go tonight or tomorrow. I wouldn't even be looking at electronics if I was only getting 1 or 2 sparks when I pushed the kicker down but this thing looks like a constant arc.
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Did you test the ohm specs for the stator and coil?
Have you pulled the fly wheel off and checked to see if the key that holds it to the shaft is sheared?
If so, while you had the flywheel off did you inspect the inside carefully for damage?
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I did check the stator, trigger and ignition coils with a meter. The ignition coil was bad and has been replaced with a good one. I have not pulled the flywheel yet but it looks like it may have been replaced at some point. There is signs of pitting on the flywheel but no rust, like it's been bead blasted. The inside of the cover is dry. I'll pull the flywheel this weekend and check it out.
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Make sure your flywheel is stamped F3T81171
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I know this sounds real basic, but your using the correct and new spark plug, right? Kinda like a dead battery may show 12 volts, but when under load it's dead. Same with a bad plug, when under compression it wont fire. Just a thought.
S
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Yep, new correct plug. I had to order it so I got 2. I tested the CDI box according the manual and it tests bad. Anybody got a CDI box for a 1987 500? I'm still going to pull the flywheel but at least I have confirmation that something ain't right, lol. I am surprised that I'm getting spark at all.
Just out of curiosity, will a later model set of electronics work on an 87 if you change the entire system? Will the stator and flywheel bolt on? I'm thinking it may be smart to update the entire system for the sake of parts availability.
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Yep, new correct plug. I had to order it so I got 2. I tested the CDI box according the manual and it tests bad. Anybody got a CDI box for a 1987 500? I'm still going to pull the flywheel but at least I have confirmation that something ain't right, lol. I am surprised that I'm getting spark at all.
Just out of curiosity, will a later model set of electronics work on an 87 if you change the entire system? Will the stator and flywheel bolt on? I'm thinking it may be smart to update the entire system for the sake of parts availability.
yes, if you change the whole ignition system, you can use anyone, that fits to the kx500...
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I pulled the mag today and don't see anything wrong with it. It has the correct number stamped into it and the magnets are tight.
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Did you test the stator with the correct ohm specs?
87-89 KX500 - 21003-1169 -
432-648 OHMS: BLACK/WHITE TO BLACK/YELLOW -
4.0-6.0 OHMS: WHITE/RED TO BLACK/YELLOW
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Yes, both coils on the stator test good. The cdi box tests bad but I've read somewhere that testing the cdi box may be unreliable.
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Not sure about the 87 but the 89-04 you can't test the CDI other then to make sure everything else works.
If everything else is in spec then the CDI must be bad.
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There is a procedure in the 87 service manual that details testing the cdi box with a meter. Mine tests bad according to the manual. I've been searching for a cdi box but they seem to be pretty scarce.
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You could always replace the whole system for something newer but I'm certain that wouldn't be cheap either..
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I don't know what kind of meter you used, but if it was a standard multimeter I doubt you can test the box without using CDI tester. CDI are pretty reliable they do go bad but not very often
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I've got a line on a complete system from a later model that I'm going to try. Hopefully this will fix it.
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It's alive! It's alive! I swapped the ignition system for a later model and she fired on the first kick! I'll bolt everything back on the bike tomorrow and take her for a spin. Yeehaa!
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Ride on man!! Another happy ending! Ain't this site the $h!t!!!
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Ride on man!! Another happy ending! Ain't this site the $h!t!!!
No, $h!t is bad.... that's why we flush it.
This site is A.W.E.S.O.M.E!!!!
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I have also a 87 kx500 with the same starting problems
I would like to know what did you replace exactly
I am ready to order parts, but I would like to make sure it gonna fit
all ignition parts from a 89-04 can fit the 87 kx500? (including the flywheel)
thanks
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I have also a 87 kx500 with the same starting problems
I would like to know what did you replace exactly
I am ready to order parts, but I would like to make sure it gonna fit
all ignition parts from a 89-04 can fit the 87 kx500? (including the flywheel)
thanks
I'm not completely sure on the 87, but I had an issue with my 88 and our resident 86-88 expert Dave916 said that I could use later model stuff. Scroll down on my build thread to find his comments.
http://www.kxriders.com/forums/index.php/topic,14629.60.html (http://www.kxriders.com/forums/index.php/topic,14629.60.html)
I think the only difference in the 87 and 88 is in the cases and transmission. The 87 is similar to the 86 in the transmission and cases, while the 88 is more similar to the 89 and up. I think both cranks and the later 89 and up cranks are similar. I hope Dave916 will see this and confirm.
We also have this handy guide on how to troubleshoot your electrical system. It might save you some money on new or replacement parts if you can figure out exactly what is wrong.
http://www.kxriders.com/forums/index.php/topic,16789.0.html (http://www.kxriders.com/forums/index.php/topic,16789.0.html)
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I replaced the stator and rotor of my 1987 kx500 with new oem parts(90-2004).
and the bike start! one kick baby! :-D
but my 87 kx500 bike smoke a lot compared to my 2000 kx500
(I put a pwk 39.5 168 52 pilot 36:1 premix ratio)on this 1987 kx500 .
like on this video (not mine)
https://www.youtube.com/watch?v=Ul2hiBzvEpI
is it normal to smoke that much??
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This is my 525 right after warm up. Does it smoke that much or more?
https://www.youtube.com/watch?v=txLSPxKpuzk (https://www.youtube.com/watch?v=txLSPxKpuzk)
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Here we go :lol:
The other thing to consider is your mix ratio.
Most modern 2T oil manufactures have a specific ratio they recommend and I do not know of any that recommend 36:1.
36:1 is a pretty fat amount of oil which can generate a lot of smoke and... here we go... make your engine run lean.
Remember... more oil means less fuel.
I know a lot of guys refer to the 32:1 sticker that came on the rear fender or their Kawasaki manual which says the same thing.
that was based on oils that have less lubrication properties ... Better to be safe then sorry sort of thing.
Fat on oil and lean on fuel can be really bad depending on your jetting, over all engine condition, altitude, style of riding, and type of fuel.
What brand of 2T oil are you using?
I run Motul 800 at 50:1 and that is a bit heavy on oil... I could run at 60:1 using Motul 800 with no issues.
All the four pokes I ride with tell me it smells good too... They should know :-D
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Here we go :lol:
The other thing to consider is your mix ratio.
Most modern 2T oil manufactures have a specific ratio they recommend and I do not know of any that recommend 36:1.
36:1 is a pretty fat amount of oil which can generate a lot of smoke and... here we go... make your engine run lean.
Remember... more oil means less fuel.
I know a lot of guys refer to the 32:1 sticker that came on the rear fender or their Kawasaki manual which says the same thing.
that was based on oils that have less lubrication properties ... Better to be safe then sorry sort of thing.
Fat on oil and lean on fuel can be really bad depending on your jetting, over all engine condition, altitude, style of riding, and type of fuel.
What brand of 2T oil are you using?
I run Motul 800 at 50:1 and that is a bit heavy on oil... I could run at 60:1 using Motul 800 with no issues.
All the four pokes I ride with tell me it smells good too... They should know :-D
I use amsoil interceptor, I stick with the safety , but I would like to follow your advice.
what ratio do you recommend with this oil brand?
thanks
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https://www.amsoil.com/shop/by-product/motor-oil/2-stroke/interceptor-synthetic-2-stroke-oil/ (https://www.amsoil.com/shop/by-product/motor-oil/2-stroke/interceptor-synthetic-2-stroke-oil/)
Product Highlights View Full Description
High-performance 2-stroke oil with an emphasis on exhaust power valves. Contains high levels of detergent additives to prevent valve sticking. Replaces manufacturer-branded oils. Injector use or 50:1 premix. Excellent in snowmobiles, motorcycles, PWC, ATVs and jet boats.