04 WR450-Relay under seat by battery??

6 replies to this topic
  • Mrmonk7663

Posted June 12, 2010 - 01:01 AM


Hey yall. What does the relay under the seat towards the rear of the battery box do? What is its purpose? The part number is yamaha 8DM–81950–00 I was messing around with the airbox and a screwdriver chipped part of it....probally is fine, but in case I hurt it I want to know what it is before I get a new one if needed. And how wil I know if its good or bad?


  • Mrmonk7663

Posted June 12, 2010 - 03:23 PM



  • Mutu

Posted June 13, 2010 - 01:35 AM


That is the starting circuit cut off relay. This is what prevents you from starting your bike in any other condition than clutch in, or in neutral. You'll need it working mate, I'd replace it. They cost about $10.

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  • Mrmonk7663

Posted June 13, 2010 - 10:26 AM


Thank you for the answer. Just what I needed to know. I appreciate it.

  • Mrmonk7663

Posted June 14, 2010 - 07:47 PM


Could this relay cause the bike not to start? What I mean is now when I hit the Ebutton all I get is a loud fast paced clicking noise coming from the junction box in front of the battery. The kind of sound that a dead battery makes or a battery with a bad connection. My battery is fully charged though. Only thing that has changed from when I started it 2 days ago was I whacked the relay behind the battery and put a hole in the plastic case most likely damaging the relay. Could this cause my faulty power distribution i'm seeing at the moment? This problem is annoying because since the battery isn't distributing the power, the bike can't start period, because their is no spark without the battery distributing power.

  • Mrmonk7663

Posted June 14, 2010 - 08:50 PM


Quick update. I removed the relay completely and tried to start with e start....now it doesn't even have the clicking noise. I put it back in and the clicking was back. Based on this I am going to determine that I broke the relay when I whacked it and put a hole in it, and evidently that relay is mandatory for starting the bike. I'll confirm this as soon as the replacement arrives.

  • Mrmonk7663

Posted June 24, 2010 - 11:27 AM


Final Update. Today I received the new relay 8DM–81950–00 I put it in the bike and the starter is back to normal, no clicking from starter relay area, starter motor engaging. So to all in the future...the relay at the rear of the seat (underneath) is tied to your starter relay...and if it goes bad it will affect your starter relay and the function of your CDI not allowing spark to go through to start. Hopefully this helps someone sometime. Thanks.


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