Finally checked my valves...

7 replies to this topic
  • stink

Posted March 13, 2005 - 10:19 PM


I have an 04 wr 450. There is just under 1000km (600miles) on it. I have changed the oil several times. This is the first time checking the valves. I checked the valves and noticed only the middle valve on the intake was good(within specs). The two outside ones were both too tight. Both exhaust valves were too tight also. Is this normal? I thought, if anything, they would loosen up after some use. I did not expect to see them without enough clearance. I checked 3 times to be safe. The piston was TDC, I looked at the marks on the cam chain sprocket to verify. Any comments would be appreciated. Thanks S.

  • mjslim

Posted March 13, 2005 - 10:47 PM


Don't worry, it's normal. The new valves and seats have a 1 degree difference in angle to get good sealing, so as they wear together initially the valves will sink into the seats causing the clearances to shrink. As you get more hours on the engine, the valves will conform better to the seats and the clearances will not change so fast.

  • stink

Posted March 14, 2005 - 10:08 AM


So, should I have my valves adjusted? I thought anything outside of specs (tight or loose) was not a good thing. You make it sound as though it is okay to leave them this way. Some clarification please. Cheers S.

  • R_Little

Posted March 14, 2005 - 10:32 AM


No it's not okay to leave it with tight valves.

He was just saying they tend to tighten over time not loosen.
It is very important to check your valves after a few rides on a new motor b/c they tighten up fast when new. Once the bike has a few hundred miles on it the valves tend to stay in spec longer.

BTW, I've had my WR for 4 yrears and never had a valve loosen.

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  • Math

Posted March 14, 2005 - 10:34 AM


Yes, you should readjust them. Look in your service manual, there is a table that explains which size pad to go based on the lash you just measured and what is the actual pad size. Take your measures, note the size of the pad for each valve, go to the table with this information. Buy the replacement pads, install and check lash. Re-install the cams and timing chain and check back just before closing the head once everything is in place.

The first time is the worse. It took me weeks to undestand this all this winter but I thnk I could do another within just one day now.

When you unmount the valve lifters (ti caps), try to do things such that you'll be able to reinstall the each valve lifter at their original place.. It is not dramatical if you don't but always better to do so.

The lifters should slide thight but easily in their place once lubricated with engine oil.


  • YamahaWR450FMike

Posted March 14, 2005 - 01:36 PM


I've only changed my oil once in 600 miles on my 04 WR450. Hope I haven't waited too long. Need to get around to the second oil change soon!

  • stink

Posted March 14, 2005 - 03:50 PM


Thanks for the clarification! Much appreciated. Cheers S.

  • 4x4ducky

Posted March 20, 2005 - 11:24 AM


600 miles = 1 oil change = WOW :) CHANGE IT!!!


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