Quantcast
Jump to content

  • Do you own an ATV or UTV? Join our Forum!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

Possible CDI for a Yamaha Champ 100CC, no spark.


Recommended Posts

Hello everyone, this is one of my first posts here 😃 , im having some trouble with the kids bike, no spark. What i measured so far at the CDI is:

 

Shutoff wire works ok

It has ground

It has connection to the ignition coil.

Pickup coil measures 325 ohm

Source coil measures 393 ohm

 

The ignition coil seems fine when i measure it. new sparkplug too. Flywheel spins and the key is in place.

Havent found a service manual for the champ so checked the pickup coil and the source coil values in a yamaha badger manual.

Is the cdi a common problem on these old machines? And where can i get a new cdi? Used ones i can get from ebay, but i have kids in different ages so i got like 10+ more years of use for it 😃

 

Link to post
Share on other sites


Yes they are known issues. If you can locate the ohms values +/- a few ohms you should be good to go. If is not the CDI I would check they charging system output. I know on a few atv’s and dirt bikes that won’t run At all without  the charging system running at all times to charge it all. 

Link to post
Share on other sites

Had some time to take some more measurments, the source coil is putting out AC 24,7 Volt when i run it on the starter. Hooked up an oscilloscope to the pickup coil and it vas about 1,2Vols up n down. So they "seem" to work atleast there is some life in them. Measured the output from the CDI to the coil and dint get any DC reading but 8V AC. I think the cdi should output DC and waay more than 8V. Turned off the light in the garage and there was actually a tiny tiny spark. My money is on the CDI atm. Please prove me wrong 😃

Link to post
Share on other sites
51 minutes ago, Finnforest said:

Had some time to take some more measurments, the source coil is putting out AC 24,7 Volt when i run it on the starter. Hooked up an oscilloscope to the pickup coil and it vas about 1,2Vols up n down. So they "seem" to work atleast there is some life in them. Measured the output from the CDI to the coil and dint get any DC reading but 8V AC. I think the cdi should output DC and waay more than 8V. Turned off the light in the garage and there was actually a tiny tiny spark. My money is on the CDI atm. Please prove me wrong 😃

CDI was my first guess. I’ve measured several over the years with an ohmmeter and the factory specs and it’s usually really quick to rule out. You should be getting a bright blue spark. Also 8 volts to the CDI could mean there’s a small section of the wire that’s pinched, chafed, or just a low battery. 8v is not enough to do anything. I’ve had to reword several bikes and Fourwheeler’s due to corroded wires. That green crust will cause a low reading as well

Link to post
Share on other sites


You can test the CDI for a short by using dvom to test between gound pin and the other pins. If there is continuity,  the CDI is shorting to ground.

Also, unhook the kill wire and then check for spark before buying new CDI.

Link to post
Share on other sites

No shorts, pulled the CDI apart now, almost got all silicone off. I post some pics later 😃 , alteast no diodes where burnt inside, no shorts in the capacitators either. I have to pull the microscope

so see at the markings to id some of the circuits.

Link to post
Share on other sites

I cant6say for sure without viewing specs, but, the pick up coil resistance appears a little high.

Check the voltage and current on that as well.

Also check the air gap on pick up.

Link to post
Share on other sites
  • 2 weeks later...

What is the uf rating on capicitor? What were the results of your test with dvom? Sounds like you missed something when testing capacitor.  8 volts seems low. Remember,  check wire going from cdi to coil. Just because it has continuity, does not mean it can carry full current.

Link to post
Share on other sites


Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • OEM Parts at Aftermarket Prices
  • Similar Topics

    • By RatpigHoosier
      Greetings and salutations. I’m new to the forum and I wish I had found it earlier. Proud owner of a really old Honda TRX350D that was gifted to me, and it certainly is the gift that keeps on giving. It is a tank and will keep up with more modern and larger machines but I can’t get it to run right so I’m about to sell it. 
      I am purchasing a 2001 Kodiak 400 in the next few days. Pretty solid and runs strong but needs the new (included in the deal) front diff, or at least that’s what the guy is telling me. Seems like a simple enough job but I’ll diagnose it once I can tear into it some.  I’m excited about it because they seem like great machines and I need something more dependable for deer season. 
      Anyhoo, that’s my story. Any advice that the forum can provide as I go along on my journey would be greatly appreciated. Thanks, everyone!
    • By Chuggs
      New member from Alberta Canada.  Currently own a Yamaha Kodiak 450.  Mostly use it for Hunting and Fishing.

      Cheers
      Chuggs
    • By Hub
      Hey,
      I purchased a 1994 Kawasaki Bayou 400 4x4 which was running fine when I had all of the plastics off and now that I have put all the plastics back on the machine I am getting some strange symptoms. With the ignition on (neutral light on) and  having the kill switch in the RUN position now have no crank, no spark. But when I put the kill switch in the STOP (or off) position the electric motor crank, but still I am getting no spark. Is it normal for the ATV electric motor to work in the off position and not in the RUN position? It wasn't doing this before. I have replaced the spark plug and the ignition coil so far.  I am wondering if something is getting shorted after I put the plastics back on? Any ideas? If it is a short any ideas how can I track it down?
      Thanks!
    • By Gadget44
      new racing cdi trz50 wiring for predator 90
      cdi has a green and yellow wire going to a 2 pin plug
      and has a red a black and blue with bullet connectors what wires go were on the the ate wiring harness
      and how would i wire if i want to bypass the atv harness
    • By PGregory
      1700 miles on the machine, all trail riding.   Second ride of the day and I get an overhead light, shut it down, let fan run, fan shuts off, light still on, ride back to camp, clean radiator, let machine cool for a couple hours.  Start up, head over to the campgrounds, ride for 5 minutes or less, overheat light comes back on and the machine blows the ignition fuse.  Tow it back, replace fuse, turn on key, fuse blows immediately.  I've ran all the wires, no mouse chews or rubbing, etc.     Does the KingQuad have a thermal protection system that would explain this?   
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...