bad cdi? maybe water is to blame....

Y

young grease monkey

New Member
i went for a ride in the snow at a park w/ a baseball field, and did some mx-style turns and roosing, tons of fun! power wasn't quite there, i noticed. i was riding around for a while, my bike was caked in snow, and about a block away from home the engine quits. there is fuel in the tank, i try choking, and bump starting really fast. nothing. so i got home, pull the plug and start turning it over and check for spark. a few sparks, but not rhythmic with the rpm. i notice the plug is gapped too much, so i close it a little and try to start it. i get a few pops but no go. i let it sit a while as i gave up, and searched the threads. even looked up how t make my own cdi 'cause i thought it was shot. then i slap myself on the forehead, and wonder why i didn't check the cdi connections! i brought the bike into the basement and the blue wire is a little loose, so i tighten the connection with some pliers and pull the kill wires, in case the kill is bad. i go around the block, peddling with the clutch engaged the whole time. i got lots more pops, almost there! i adjust the choke and it starts up a little, then more, and it finally runs! top speed is quite low, about 20. what do you think happened? water in the cdi?
 
have you tried striping and cleaning out the carb maybe its cloged with watter "oil and watter dont mix"clean the magneto and stator plate with a little carb cleaner my coil wires i did away with those cheap conecters and soldered them, make sure coil is earthed to motor well "i had trouble like this" ,i also pluged the hole where the wires come out of the motor case with sillican .... maybe try these first before deciding to change a coil
 
Mine did that(minus the water) and it was a bad magneto. I understand the CDI is a sealed unit and filled with resin, but I have never taken one apart.
 
I've had a similar problem and it was the mag not the coil. The white wire's solder joint was weak and caused intermitent spark. Just re soldered and 2000 miles latter still all good. Like was said put some silicon where the wires come out and I put some around the spark plug wire also where it connects to the coil.
 
bluenosegoat said:
I've had a similar problem and it was the mag not the coil. The white wire's solder joint was weak and caused intermitent spark. Just re soldered and 2000 miles latter still all good. Like was said put some silicon where the wires come out and I put some around the spark plug wire also where it connects to the coil.
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Just a question, what does the white wire have to do with current running to the CDI. The white wire has nothing to do with the engine operation, unless it shorts out on the frame or engine. In fact I remove the white wire completely, thus there is no chance of contact with the frame or engine. This is of course, if you don't have any intention of using a small wattage light bulb. Now I do resolder the blue wire in case there is a bad solder job or cold solder joint. I also have had 1 magneto go out on me and it was 3 days in the running.
 
ok, so check the mag, and nothing i can do if it is the coil? i thought it might be that that the capacitor is not getting enough juice to fire every time? it sort of works now, but lots of 4 stroking
 
Al.Fisherman said:
Just a question, what does the white wire have to do with current running to the CDI. The white wire has nothing to do with the engine operation, unless it shorts out on the frame or engine. In fact I remove the white wire completely, thus there is no chance of contact with the frame or engine. This is of course, if you don't have any intention of using a small wattage light bulb. Now I do resolder the blue wire in case there is a bad solder job or cold solder joint. I also have had 1 magneto go out on me and it was 3 days in the running.
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Ya my mistake! I remove the white wire also. I've had a few mags with poor solder joints that took me forever to diagnose. If I remember correctly (been awhile) the problem was usually at the winding where the wire comes out.
I cant remember the parameters for ohm's testing the mag but its in the forum somewhere- might be something to check out. I might be mistaken but I think in .350 range is where you want it, much lower than that will cause a weak spark.
 
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problem fixed! i moved the carb needle clip up one notch(leaner) and found a magneto from the engine i sent back to gasbike, (but took out a bunch of stuff to save on shipping so now i have some spares) and it runs great. then i hot glued the screw holes on the mag cover because they don't seal, and all the wires on the mag and cdi box. fun time! the clutch started slipping because it had power back now, so i fixed that and the crappy clutch handle that didn't hold the lock position far enough. t'was a good day.
 
bluenosegoat said:
I cant remember the parameters for ohm's testing the mag but its in the forum somewhere- might be something to check out. I might be mistaken but I think in .350 range is where you want it, much lower than that will cause a weak spark.
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The information is in the DOC that I gave a link to above..did you not read it?
 
i think i found part of the problem. it started doing the same thing again, but i heard a clicking noise like the spark is jumping somewhere. turns out, the spark plug insulator was bad. it was an ngk, and only had about 6-7 hours on it. bummer. so i put in one of the crappy plugs that come with the kit, problem fixed. i will got to an auto store tomorrow and get another plug
 
bluenosegoat said:
Ya my mistake! I remove the white wire also. I've had a few mags with poor solder joints that took me forever to diagnose. If I remember correctly (been awhile) the problem was usually at the winding where the wire comes out.
I cant remember the parameters for ohm's testing the mag but its in the forum somewhere- might be something to check out. I might be mistaken but I think in .350 range is where you want it, much lower than that will cause a weak spark.
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as for that white wire as some one mentioned in the above post that wire is 6 volts out im not sure if its dc or ac curent if its ac you will need a regulator so yyou can use it for chargeing a battery or running 6 volt light but i agree with the other guys you just chop this strait off as it bearly provides enogh curent to run anything even a few leds or the tiny'st lanten globe will bog the crap out of the motor when you turn it on
 
Al.Fisherman said:
For reference the white wire ........AC out put.
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Ya the alternating current has a big potential for blowing bulbs without a regulator-the amperage increases with the rpms. I've seen it used to charge a 6v motorcycle battery to power the lights which is a neat idea but the size and wiring of a battery is hard to conceal on one of these bikes.
 
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