I have a new age 150cc 4 wheeler that starts and runs great but then when it warms up it dies. Let it cool off for 5 or 10 minutes and it fires right up. i have other mini bikes,4 wheelers etc with the exact same parts and have tried swapping everything that's interchangeable starting with the coil and have had no luck. Any input would be great!

 

When it dies and won't start, *quickly* check to see if you have spark. If you don't then we look there at the ignition system. If you do then it's on to fuel issues, etc.

To check for spark, pull out the plug and wire it back up. Hold the plug threads against the engine block and try to start the quad. It won't start of course, but do you see a steady spark across the plug gap at about 10 times per second?

But remember, you have to do this test while your quad is not starting. Ideally, you need to do this test while the quad won't start, and then reinsert the plug and verify that the quad *still* doesn't start after the test. Otherwise you don't know if the quad was still malfunctioning when you did your test.

 

Well ive got several of these little bikes and atvs that all have the same stuff and have tried swapping out everything electrical. The spark did vary a little with one coil. It wasnt consistant but it did fine on my other 4 wheeler. I can unplug the cdi completely and it still runs which baffles me. Ive thought about it being a fuel issue but everything seems fine. Possibly a valve sticking when it heats up?????

 

Nope. Not possible. You're confused. If you unplug the CDI you will have no spark, and the engine will not run. End of story.

I think you're misidentifying the CDI and actually unplugging something else. Do a google search for 150cc CDI and look at the pictures. Find a picture that matches something on your quad so you know what your CDI looks like.

Most 150cc CDI have 6 pins - a 2 pin connector and a 4 pin connector.