2006 WR450 Valve adjustment

7 replies to this topic
  • RIP_PonyExpress

Posted February 20, 2015 - 08:36 PM


I had a post on here about a year ago http://www.thumperta.../#entry11540068


Basically, I had an electrical issue of a dead battery everytime I road the bike 50 miles or so and the bike could not be started.  I had replaced the battery (twice), stator, voltage regulator, and finally wiring harness.  I had mentioned that when the battery was dead, I could not start the bike even by kick start.  I believe I have resolved the electrical issue as the last ride I went on, I had stopped but the bike would not start, but the starter was at least turning.   People had mentioned that the bike does not need a battery to be kick started so it appears there were multiple issues with the bike.  Prior to replacing all the electrical components, I had the carburator tuned and the valves adjusted.  The mechanic told me the valves needed adjustments and did the work. 


Anyhow, I still have the WR450 sitting in my garage and tore into it today.   I checked the valve clearances and found the exhaust in spec, but the intake was 0.0015"; I can not even fit a 2 thousandths feeler guage in it.  According to my book .0039 is the miniumum. 


So the question in my mind is: did the guy mess up, or do I have a more serious problem?


Does the clearances close on wear?


I may note that the bike never got past 300 miles after he serviced it.


I have talked to a number of folks about the problem and they indicated that the top end needs rebuilt.  Further they state that if I rebuild the top I should put a new piston and rings in it.  Before I know it, they want $1500 to fix the darn thing.  Probably should note that the bike has about 8-9k miles on it.


Is there really anything I should do other than put a new intake valve in it?







Edited by RIP_PonyExpress, February 20, 2015 - 08:43 PM.

  • flyandride

Posted February 20, 2015 - 09:49 PM


Valve clearances get tighter as they wear.  Once the hardened coating wears off titanium valves, they wear quickly.  They can go from in spec to tight in 300 miles.  Had it happen to a WR of mine.  So the guy probably didn't mess up, he probably shimmed to spec and they got tight again.  Ask him or look at the receipts, what size shim did he go to?  If it's down to a 150, that's a dead give away that the valves are wearing out.  Down to a 120 and valves will tulip soon.  

You can't just put in a new valve.  The seats have to be cut to match the valves.  The springs and seals should be replaced at the same time.  Best to send the head off and have it all done.  

Don't bother just replacing the piston and rings.  Get on ebay and buy a Cylinder Works bore kit for around $400 for either standard or big bore.  It includes the piston, rings, new cylinder and gaskets.

And while you're in there, replace the timing chain and tensioner, not expensive.

No one ever said dirt bikes are cheap.   

  • toten

Posted February 20, 2015 - 11:46 PM


I agree with flyandride, a +3mm bore would be a nice upgrade if you're looking at touching the piston. <$400 for cylinder, piston, rings, gaskets. 


What's the difference between early (03-06) and late (06-14) WR cylinders? What's a good compression ratio to go with to run on the 91 octane pisswater we get here in CA? Or maybe even 87, sometimes that's all that can be found. 


Where's a good place to send the head? If it needs a valve job might as well have a little porting done. Depending on what sort of riding you do, bigger cams might make sense. Clearly, everything snowballs to a certain extent... skipping the cams and just having the head cleaned up/valve job would save you some money.

  • RIP_PonyExpress

Posted February 21, 2015 - 05:19 AM


So cylinderworks website shows overbore kit at $600 and standard bore kit at $560.


Is there a recommended place for heads?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • flyandride

Posted February 21, 2015 - 06:31 AM


So cylinderworks website shows overbore kit at $600 and standard bore kit at $560.


Is there a recommended place for heads?

Don't look at their website, go to ebay.  I just looked.  $409.95 shipped for the 478 kit.  I sent my head to M Tech, which was recommended by friends.   http://www.mtechmotorcycles.com/

  • RIP_PonyExpress

Posted February 21, 2015 - 07:21 AM


Given that I have a 2014 ktm450, I am not sure I will keep this bike.  I have had people tell me to reshim and sell, but that really seems immoral as it will likely be a few hundred miles and the guy I sold it to will be knocking on my door.


Ok, if sell the bike my inclination is to get an intake valve kit, and possibly hone the cylinder, and put some rings in it.  Maybe a new timing chain.  I would think that should get the bike going for a few seasons.  If I am to keep the bike, probably do the bore kit, and professional head rebuild.


So I think we all agree it needs new valves, what kind should I get, Stainless Steel or Titanium? Stainless are said to last 4x longer, but the extra weight will probably take away the motor's ability to rev high?

  • stevethe

Posted February 21, 2015 - 10:18 AM


Wondering if the guy that did the valve adjustment just got it off. I would adjust the valves to the proper spec. and give it a run. WR's go a long long time.

Edited by stevethe, February 21, 2015 - 10:18 AM.

  • Krannie McKranface

Posted February 21, 2015 - 12:55 PM


Inspect everything inside before jumping to a big bore kit.

Properly jetting the WR450 runs FANTASTIC and doesn't need a bigbore kit...


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.