My Yamaha YFZ450 Has No Spark

When a Yamaha ATV has a no-spark condition, what else do you check besides the stator and spark plug? Partzilla's powersports pro John Talley offers tips for troubleshooting a Yamaha YFZ450 with no spark.

John does Q&A livestreams every Friday at 3pm Eastern on our YouTube channel, and in this edition, he offers advice to one of our viewers who has a Yamaha YFZ450 lacking a spark after the clutch cable made contact with the starter wire.

Yamaha YFZ450 No Spark

I have an 06 YFZ450 and my clutch cable touched my starter wire and now I have no spark. I checked the stator and the spark plug. What else could it be? 

John Talley: Obviously it upset something in there, and well it’s a very simple system, so what do you have? You’ve got your CDI, which is basically your ECU, then your coil, and then the spark plug. Pretty simple. Let’s hope that it may have just overheated a wire. I don’t know how long it stayed connected to your clutch cable, but could it have potentially tried to ground it or sent the ground all the way up to the handlebar and maybe gotten into your cutoff switch? Let’s start with the simplest thing first. Make sure that cutoff switch didn’t try to act like an engine ground with that much current going through your clutch cable. Just a thought, but maybe that battery voltage was trying to get to ground and it didn’t care which way it was going, looking for the path of least resistance. Check the kill switch on it. Hopefully it’s something as simple as that. Other than that, you may have to get another ECU. Take a peek to see if that’ll take care of it, but I’d check everything else first before ordering an ECU. 

Watch the video above to see how to do a clutch cable replacement and adjustment on a Yamaha YFZ450 ATV.

Watch the video below to see how to troubleshoot charging system problems on a Yamaha YFZ450 ATV.

Want to see more live repair questions answered? See more motorcycle and ATV repair questions answered here.