2012 WR450 Blowing Blue Smoke & Ticking/Knocking

11 replies to this topic
  • dillon906wr

Posted October 09, 2015 - 03:50 PM


Hi Everyone! This is my first post on TT so hopefully I can be clear and concise to help get pertinent info across to solve my issues. 


I have a 2012 WR450F that I bought new less than 2 years ago.  I have appox. 100 hours on the bike. 

Just a few weeks ago my bike began blowing blue smoke when I rev the throttle and has a ticking/knocking noise that seems to match the rate of the piston.

I decided to pull it apart and found that a few things that seemed odd for a bike this new: 

1. The intake valves are oily and have a lot of carbon build-up.

2. The top of the cylinder wall is slightly scuffed on two of the sides.  


I also have a 2008 YZ450F that has had no engine problems and has been ridden hard, so these issues seemed premature to me.  The only modifications I have done to the bike is the green sticker un-corking and an FMF Q4 slip-on muffler.  I had my fuel and ignition mapping adjusted in January of this year.  The technician that helped me set most of the numbers on the chart +1 above the recommended for my setup. I have attached a picture of the chart with my settings vs. recommended. Seems too moderate of an adjustment to cause these issues, but it is the only thing I can think of at this point.

I would greatly appreciate any help.  I find these forums to be a very useful tool.WR450F Head.jpg WR450F Piston.jpg WR450F Cylinder.jpg WR450F Cylinder 2.jpg WR450f_PowerTunerChart.jpg

  • Krannie McKranface

Posted October 09, 2015 - 04:04 PM


You need to look at the piston.

Sounds like you had a stuck ring, and now a worn out piston.

  • stevethe

Posted October 09, 2015 - 04:47 PM


Was it overfilled with oil or run with no or little oil. There is too much oil on the top of your piston and head.

  • MidlifeCrisisGuy

Posted October 09, 2015 - 10:04 PM


I think the injector is dribbling and it washed down the cylinder.  Look how rich the plug is.

  • dillon906wr

Posted October 10, 2015 - 06:48 AM


Thanks you guys for the input. I took a good look at the piston, and from what I see it looks to be in good shape. As far a oil, I have always been very up on changing (about every 3rd ride) and fill with recommended 1qt. I haven't even thought about the injector issue, but I will pull the plug out and report back

  • DPete

Posted October 10, 2015 - 08:03 AM


Did the engine possibly get dirt?

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  • schrode

Posted October 10, 2015 - 08:09 AM


just mic the cylinder and rebuild as needed.

  • Krannie McKranface

Posted October 10, 2015 - 11:48 AM


You need to measure the piston and bore

All that blackness is coming from somewhere

I would do a leak test on the head

  • dillon906wr

Posted October 12, 2015 - 09:21 AM


I am going to have the head and cylinder sent in to be rebuilt.  I took and intake valve out and then an exhaust valve.  The intake side looks great.  The exhaust side not so much, it had a lot of carbon and oily build up on the stem and near the seat.  The cylinder wall had scuff marks at the top that seem to be substantial enough to let the oil by and I'm assuming was where the tick/knock came from.


Do you guys have any recommendations for a good shop that does head rebuilds and/or cylinder re-plating?  I live in Snohomish,WA, but I am not opposed to shipping it out if anyone has a reputable shop they recommend.   Again, thanks for all the input everyone.

  • stevethe

Posted October 12, 2015 - 11:22 AM


Send it to http://www.mt-llc.com

  • dillon906wr

Posted October 12, 2015 - 12:14 PM


Thanks Steve!  I have heard of this company from a few other friends I ride with also.  Sounds very promising.  I will give them a shout.

  • stevethe

Posted October 12, 2015 - 01:07 PM


Thanks Steve!  I have heard of this company from a few other friends I ride with also.  Sounds very promising.  I will give them a shout.

They should be able to tell you what it needs and what it doesn't need.


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