1998 YZ400F NO SPARK?!?

3 replies to this topic
  • Craig1776

Posted November 21, 2015 - 08:51 AM


I recently bought a 98 yz400f for a $700. The bike had no spark but for $700 I thought I could easily find the problem and already be riding the thing. I started with the kill switch, that wasn't the problem. New spark plug...nope. I tested the stator and the numbers seemed to match what the manual said. So I bought a new CDI and a new Coil, put them on and...nothing. Is there anything I'm missing? Any help would be greatly appreciated! Thanks!

  • Caleb99olsen

Posted November 21, 2015 - 12:11 PM


Check for any broken wires for the stator or anything check them all. And also check for a corroded ground? That's just a guess but worth to check

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted November 21, 2015 - 12:21 PM


It won't start, so you think it has no spark, or it actually has none by test?  Most of the time, problems with making an old 400 or 426 run for the first time in a while are in the carb.


But if you really have no spark, ring out the harness and check the grounds as suggested, then back probe the connected harness at the voltage inputs to the CDI.  Use an analog meter or a DVOM with an analog scale in the display and test for AC voltage while you crank.  You should get something like 5 volts on one and 9-10 or so on the other. 

  • Craig1776

Posted November 21, 2015 - 03:44 PM


I've tested for spark and it was non existent, but I will try what you just said, thank you!

Related Content


Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.