Cam Plug popped out-anybody seen this?


9 replies to this topic
  • wardirt1

Posted August 21, 2007 - 08:40 AM

#1

I was riding my 2004 wr450 a couple weeks ago and my buddy noticed a quick puff of white smoke out of my bike. Later I noticed a small dripping of coolant from the radiator. Since I couldn't repair it right away and it was slight dripping and somewhat intermittent I did another 50 mile ride on it before I pulled the radiator off. When I did I noticed a plug missing on the cylinder next to the exhaust connection. From looking on-line I think it is a cap to access the cam chain. Has anyone else had this happen? Do you think I may have done any damage riding with it out?

  • mbraun777

Posted August 21, 2007 - 12:07 PM

#2

Does that cap hole have two small threaded holes next to it - one on each side? If so it could be your cam chain tensioner fell off. If so don't even start it.

  • WGP

Posted August 21, 2007 - 01:12 PM

#3

Sounds like the decompression plug fell out, common on 04 and older YZ/WR's
Do a search on that in the YZ forum.....easy fix:thumbsup:

  • tp3dxf

Posted August 21, 2007 - 10:59 PM

#4

Sounds like you lost your deco plug. Where was the radiator leaking from?

  • tp3dxf

Posted August 21, 2007 - 11:11 PM

#5

Does that cap hole have two small threaded holes next to it - one on each side? If so it could be your cam chain tensioner fell off. If so don't even start it.


Cam chain tensioner is located on the back of the motor. If that is missing I wouldn't start the bike either.

But from what you described sounds like the deco plug blew out which is located on the front of the motor above the exhaust header. Not a big deal. I bought one here on TT which I have never used. I just left the stock one in when I changed out my cam for one with auto deco built into it. I did pull off the deco lever and cable.

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  • BOBR

Posted August 22, 2007 - 08:50 AM

#6

I had the same thing happen to my 04'. I bought a new plug and added a little RTV Silicone to it when I put it back in. Never had another problem.

  • mbraun777

Posted August 22, 2007 - 09:56 AM

#7

Cam chain tensioner is located on the back of the motor. If that is missing I wouldn't start the bike either.

But from what you described sounds like the deco plug blew out which is located on the front of the motor above the exhaust header. Not a big deal. I bought one here on TT which I have never used. I just left the stock one in when I changed out my cam for one with auto deco built into it. I did pull off the deco lever and cable.


Yall are right. :eek: Those decomp plugs are known to pop out. Installed one I bought from TT as well though mine hadn't popped out. Had to take off the valve cover to knock it out. It did take me another swig from my beer to accomplish this.

  • wardirt1

Posted August 22, 2007 - 02:05 PM

#8

thanks folks, it was the decompression plug. I figure I put 40 miles on it the day if popped out (after it popped out) and another 35 of dusty single track on the next ride before I discovered it. Looks very clean inside the passage way but it obviously spit out oil. Ran great to the end although it seemed to stall out a bit more frequently. There was a great thread on TT about it, hoping I did not do any damage. I am assuming the + pressures have kept me out of trouble. I am thinking that when it blew out, it damaged the radiator, can't think of any other cause for small leak and the timing is right but have not had it pressure tested yet to isolate the leak.

  • JimL

Posted August 24, 2007 - 02:30 PM

#9

check and see if your breather hose is pinched, I removed my bracket to keep this from happenning and used a zip ty instead . I have personally seen this happen twice due to this. then buy the plug from thumper talk store. It's held in by the screw previously used to hold the decomp lever.

  • tp3dxf

Posted August 27, 2007 - 02:03 AM

#10

check and see if your breather hose is pinched, I removed my bracket to keep this from happenning and used a zip ty instead . I have personally seen this happen twice due to this. then buy the plug from thumper talk store. It's held in by the screw previously used to hold the decomp lever.


I pinched my breather between my skid plate and frame once. After about 20 miles I noticed a bunch of oil spray on my left boot. My riding boots. I stopped and took a look and sure enough I had blown the top end rubber gasket off the left side of my motor.

I was totally freaked out but with some small flat blade screw drivers and a little oil I did finish the ride. Still use the same gasket to this day. It really was no big deal. But to this day I always check that thing.




 
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