So I followed my bro down to deliver a wheeler that he worked on and when I got back I noticed oil all over my '04 yfz450. I the hole where it was coming from and after a little research found that it was a decompression plug.

What does this do? What is it for? (Besides draining the oil of a running engine?)

 

yet another victim... I too blew mine out before I replaced it... To be honest, I have no idea why yamaha initially put it in there. Or why they designed it to be so weak. They of course learned their lesson and covered it up permenantly on their `05 on up models of the yfz...

 

Luckily I only rode about a mile maybe mile and a half. Not sure when it popped but I'm hoping I haven't cause any damage. Time will tell.

 

I doubt it... How long ago did change the oil before it happened? The most damage you probably did was to the radiator and header when the oil leaked everywhere... Definitely lucky it didn't catch fire... (some people's have) I had to ride mine about a mile when I found out that I blew it out... luckily we smelt burning oil, because it was dark out so I never would have seen it...

 

Ya.....good point. I changed the oil about 3 weeks before. Prob only hour of riding time since. Oil clean as a whistle but, seen it soon as got off the wheeler because the black oil reservoir was wet. Radiator is in direct line of fire as you said.

So any advice on what I should watch out for outside, overheating issues and exhaust leaks?