I have a star 200cc atv that runs strong for around 20 mins or so and will then just die. When it dies it loses spark. Then it has to sit for a few hours and then it will re start again. I think its the cdi box. When it died, i disconected the cdi and put it in a warm place and sat it their for like 10 mins or so and then reconnect it. it seems to start again. Sounds werid but it works for some reason. Any thoughts would be great!! THanks alot!! im thinkin cdi though

 

I've not heard of a star 200cc ATV. Is it chinese?

Maybe its your CDI but I don't know why it would cool that much faster when unplugged. The CDI is normally mounted well away from hot engine parts, and when riding the moving air stream would keep it near ambient temperature anyway regardless of how hot the engine gets.

For spark you need a good Stator, CDI, coil, Spark Plug, functioning Kill Switches, and all the wiring in between. With a volt/ohm meter you can completely measure for proper stator operation and most of the CDI. All of the wiring and kill switch operation can measured as well. You can measure the ignition coil windings for continuity, but you really can't test for temperature related or voltage breakdown problems except by substitution.

I would at least eliminate those items that can be measured first. Then start shotgunning. It is frustrating when you change everything and it still doesn't work, eventually finding out it is a loose connector pin which can be fixed by squeezing with pliers.

How many pins does your CDI have? Do you know if it is DC powered or AC powered?

 

Im not sure if its dc or ac powerd. Ill post a pic up soon of it. It has a plug with 4 pins, and then a plug with two pins. What and where should i be checking with a muiti meter to test the cdi and such. Thanks for the help

 

heres a pic of the cdi

 

At first when I read that the CDI had 4 pins plus 2 pins I was thinking your CDI is the same
as mine on a 150cc GY6 quad. But when I looked at the picture it isn't quite the same.
Mine looks like this:



Notice the connectors aren't quite the same, but maybe it is just the connectors and the
internal parts are the same. See the following eBay link for a CDI like yours which also
supposedly fits 150cc machines.

http://cgi.ebay.com/ebaymotors/CDI-I...Q5fAccessories

Assuming they are the same pin out let's proceed cautiously. Note: All the following
measurements must be done when the quad is in the "malfunctioning" condition. While
proceeding plug everything back together every so often and make sure it is still not
working before drawing conclusions. You don't want to get clear to the end with the
answer that everything is working fine, plug it back together, and have it start right up
only to fail again a while later.

First lets determine if the CDI is DC or AC powered:

Disconnect the CDI from the wiring harness. Turn on the ignition key and measure from
the ignition power connection in the harness to engine ground. If it reads 12 VDC then it is
DC powered. DC powered CDI's have a DC to DC power convertor to take 12 volts and
convert it to 130 volts or so to drive the ignition coil.

If it reads zero volts then switch the voltmeter over to AC volts on the 100 volt or higher
scale. Crank the engine while measuring the Ignition power connection in the harness to
ground. If it reads around 80 VAC then it is AC powered. You must have the CDI
disconnected when measuring this or you will get meaningless results. 80 volts AC when
rectified and filtered makes around 130 volts DC to drive the ignition coil. If you get 80
volts AC then it means your stator ignition power winding is working also.

If you get results different from either of these two scenarios then we'll have to think some more...

While cranking the engine measure the Ignition Trigger Pulse connection in the harness to
ground. This should measure from 0.1 to 0.4 volts AC. This is actually a complicated
waveform that has very narrow plus/minus spikes at a low repetition rate so voltmeters
don't do well with this measurement. Different meters read differently, but you should
measure something other than zero volts AC. This signal from the stator tells the CDI
when to dump the high voltage it has accumulated from the stator or DC/DC convertor (a
hundred to three hundred volts DC) onto the ignition coil primary.

On your ohmmeter setting measure the kill switch connection in the wiring harness to
engine ground while the ignition switch in ON and the engine is stopped. It should read
open, or very high (infinite) resistance. If it is shorted to ground you will get no spark.
The kill switch circuitry works by shorting the high voltage supply in the CDI (100-300 volts
DC) to ground, preventing any spark through the ignition coil.

Use the ohmmeter to measure the Ignition coil primary connection to engine ground. It
should just be a few ohms. The ignition coil is just a transformer that steps up the few
hundred volts on the primary side to a couple tens of kilovolts on the secondary side to the
spark plug.

Also measure the ground connection in the wiring harness to engine ground. You need at
least one of the two.