ok i got my son a 50cc baja dirt runner it ran ok for a little whiel but then went bad!!! ok it started bogging and backfiring. changed plug no good checked for spark no spark so started checking voltages nothing comming from magnito any help?????

 

Well you need a manual for it or to talk to someone who knows something about them. YOu can get a service manual from baja motorsports for them I believe. They also have parts books for them online too I think. This site has lots on info on those little baja bikes http://www.4strokes.com/forums/default.asp?CAT_ID=28

Is this thing brand new...if so maybe its just something simple like a loose wire. Watch out for the airfilter on these little things they are not very good!!!! My kids have one and the little thing though cheaply built works pretty good. Only real issue is the darn air filt the way its mounted, the mud and dirt flies off the rear tire right into the air box!

 

i have the service manual and have been reading like crazy tring to figure this out. it ran the same with or without the filter while working on it i had it off the carb is clean i have cleand it twice in the last week i had it running ok but it lost its spark. tried cutting the black wire with the white stripe comming from the cut off switch didnt do anything. the bike is like 2 years old but has only been used a few times so its pretty much brand new. when its running its great and fast.

 

Well is there not a "no start" flow chart of things to check when you have no spark? I would think in that little bike you have the ingnition coil, CDI unit and the Stator that supplies power and some sort of pulse generator that gives the singal to the CDI unit which sends the on/off singal to the coil.

 

not sure what you are talking about there but i have adjusted the magnet on the magnito still got nothing checked the magnito with a volt meter still nothing can you be more specific about the no start flow chart?

 

i have also posted a thread on the 4 strokes .com site

 

Cutting the black/white wire on the CDI disconnected your kill switch(es). So we can eliminate shorted wires and/or bad switches there.

Here are two common CDI's. Do either of these look like yours?






If so, identify the wire that provides AC ignition power. On my quad it is Black/Red, yours may be different. Unplug the CDI and measure the resistance of that wire in the wiring harness to engine ground. You should get a few hundred ohms. Report back what you measure. Next, measure the voltage on the same wire to engine ground wire cranking the engine. Do this with the CDI disconnected, and make sure that the voltmeter is set to measure AC volts. Report back what you measure for resistance and voltage. CAUTION: If the stator is working you will measure high voltage while cranking, so make sure you aren't part of the circuit while doing this.

Find the Timing Trigger wire. Measure the resistance of this wire to ground, same as you did for the AC Ignition Power wire. Report back this measurement. Also, same as before, measure the AC voltage on this wire while cranking. Expect low voltage on this line (less than 1 volt AC). Report back exactly what you measure.

When you report back I need exact measurements like "563 ohms to ground" or "38.5 volts AC", and not "It measured good" or "I got nothing". The latter two are not going to help very much.

What do you mean by "I have adjusted the magnet"? I've never seen an adjustable magnet on a stator (magneto). What magnet? Where?

 

i will check the voltages shortly. the magnet i am talking about is on the side of the magnito it has a small spot that hits it. i am guessing this sends the voltage to the cdi when to spark. the first cdi you posted is like mine. thanks for your help

 

ok black /red .374
next i got 84 as the highest ac voltage this is a kick start bike so this was hard to test.
the next test was the timing trigger wire i got .4 volts ac again this is a kick start bike so its hard to know if thats right or not now that i am typing this i wonder if i move the magnet if i can get i higher voltage on the timing trigger. i think thats what the magnet does it hits on a little part that sticks out and sends the voltage thrue the magnet am i right on that???

 

THe magnet shoud not rub against anything, there needs to be a little air gap.