Valve Clearance


13 replies to this topic
  • frdsrck

Posted January 28, 2008 - 03:25 PM

#1

I decide to finally check the Valve clearances now that I have hit 1000km.

They are pretty tight. :applause: Exhaust are like 0.08mm, (tolerance is 0.20-0.25) and the Inlet's are at about 0.06mm (tolerance is 0.10-0.15).

Has anyone else checked their KLX450 yet :cool:

How hard is it to put shims in? I don't have a full service manual, but I guess I should probably get one if I am going to do this myself?

  • mxphlipper

Posted January 28, 2008 - 04:10 PM

#2

Thread for service and parts manual

http://www.thumperta...ighlight=manual

  • Naz88

Posted January 28, 2008 - 07:39 PM

#3

One question, Does your bike start? If the answer is yes, I would ask you to be sure and double check. I don;t think your bike should start if the valves are that out of spec.

I check mine and at 1500km, one exhaust valve tightened up to 0.19, all others were within spec. My bike was under warranty still so I opted to have the dealer change the shim, I believe it cost me just under $100 with taxes at the time.



I decide to finally check the Valve clearances now that I have hit 1000km.

They are pretty tight. :worthy: Exhaust are like 0.08mm, (tolerance is 0.20-0.25) and the Inlet's are at about 0.06mm (tolerance is 0.10-0.15).

Has anyone else checked their KLX450 yet :busted:

How hard is it to put shims in? I don't have a full service manual, but I guess I should probably get one if I am going to do this myself?



  • frdsrck

Posted January 29, 2008 - 07:53 AM

#4

Yes, the bike starts and runs good as well. I also thought that it should not have been running that well if they were that out of spec. I have a buddy who said he will help me double check them..... tough to get the feeler gauges in there properly!

Thanks for the thread to the manuals.

  • Thomas6x

Posted January 29, 2008 - 09:04 AM

#5

All I have are KXFs
This comes from my drag racing days.
with 0 clearance odds are your valves may not close,thus bike won;t start or runs poorly.
here is the kicker, with tighter clearance you get more lift out of your cam profile and in turn may run better.
Don't get me wrong and close up your clearance.
The preformance may not out weigh your reliablety.
:busted: :worthy: :ride: :blah:

  • Naz88

Posted January 29, 2008 - 09:05 AM

#6

Yup with my one exhaust valve tight it was more difficult to start the bike, yours shouldnt start at all. Once the valve clearance was fixed the bike fired up right away, thats actually why I checked them was because the bike was getting more diffcult to start

  • KLX450R

Posted February 01, 2008 - 05:56 AM

#7

Hey guys let me clear up something for everyone here and future readers of this post!

Valve clearance is necessary for the bucket(or cam follower) to allow sufficient room for oil to be retained on the cam lobe and prevent scaring of the hardened surfaces. This clearance also allows room for parts to stretch, flatten, or wear in general. The valve stem will stretch, the valve seat will flatten, and the valve head will wear minimal amounts through-out the life of the motor. The clearance prescribed allows you time between motor servicing to actually get out and ride with out having to tear down and reshim after each ride.
A motor with slightly tighter clearances than prescribed WILL CRANK AND RUN, although when they are nearing 0 clearance the motor will become difficult to start from lack of compression or the ability to retain the proper fuel air mixture for combustion. You will experience more cam lobe wear over the life of your motor if you generally service your valve clearance less than prescribed and they run tighter than prescribed. Also dirty or non specified oil will also add to this wear.
With this race motor the prescribed checks like all other 4-stroke race motors require more attention, and without that attention you run the risk of burning a valve, seat, or worse dropping a valve head through the piston and driving it into the head.
So take a minute to remove the tank, slip off the cam cover and give 'em a bit of love!:busted: They deserve it!

  • frdsrck

Posted February 01, 2008 - 10:18 AM

#8

Turns out my valves are all within the Specs after the first 1000km. I am just a retard and was comparing my imperial (thousand of an inch) readings to the metric readings in the owners manual. :busted: Once I got the full service manual, I realized that both metric and imperial are printed.

It's all good now. :worthy: Back to the Ice tomorrow!!! :ride:

Thanks for the info.

  • koleff

Posted February 28, 2008 - 01:32 AM

#9

I was open mine after 100 km.Exhaust are 0.21 / 0.24 and inlet 0.11/0.13.After 500 km I was open again and the result is:

0.21- go to 0.26
0.24- 0.27
0.11- 0.13
0.13- 0.14

I will open after another 500 km and post the result.

P.S. I saw that have a difference in exhaust gap in owner's manual (0.20-0.25) and in service manual (link posted in this thread)- 0.17-0.22
Do you know what is the corect value.

  • frdsrck

Posted February 28, 2008 - 10:06 AM

#10

I also noticed the difference in tolerances between the service manual and the owner's manual. Mine were right around the 0.21 mark so I didn't worry about it.

I think I trust the service manual more though. I have noticed some other small errors in the owners manual.

  • Naz88

Posted February 28, 2008 - 12:39 PM

#11

There is errors in the service manual too...

  • Kwik Kwak

Posted March 04, 2008 - 11:45 PM

#12

I think I trust the service manual more though. I have noticed some other small errors in the owners manual.

In general I would agree but in this case I think the Owner's Manual is correct.

My reasoning being that I converted my WR from Titanium Valves to Steel so I had to use Steel Valve clearances which were generally bigger by 0.05mm. The exhaust valve clearance of 0.17-0.22mm in the KLX450R Service Manual is the same as in the KX450F Service Manual, but the KX450F has Titanium Exhaust Valves rather than the KLX450R which has Steel Exhaust Valves.

Therefore I think the larger 0.20-0.25mm exhaust valve clearance specified in the Owner's Manual is correct and the KLX450R Service Manual is incorrect because the people who produced the manual simply copied over the KX450F manual and forgot to adjust the spec.

  • koleff

Posted March 06, 2008 - 03:06 AM

#13

In general I would agree but in this case I think the Owner's Manual is correct.

My reasoning being that I converted my WR from Titanium Valves to Steel so I had to use Steel Valve clearances which were generally bigger by 0.05mm. The exhaust valve clearance of 0.17-0.22mm in the KLX450R Service Manual is the same as in the KX450F Service Manual, but the KX450F has Titanium Exhaust Valves rather than the KLX450R which has Steel Exhaust Valves.

Therefore I think the larger 0.20-0.25mm exhaust valve clearance specified in the Owner's Manual is correct and the KLX450R Service Manual is incorrect because the people who produced the manual simply copied over the KX450F manual and forgot to adjust the spec.


I thing that owner's manual is correct,too.BTW, what is valve clearens for WR with steel valves, 0.25-0.30???

  • Kwik Kwak

Posted March 06, 2008 - 11:27 AM

#14

I thing that owner's manual is correct,too.BTW, what is valve clearens for WR with steel valves, 0.25-0.30???

Valve Clearance for a Yamaha WR426 fitted with Yamaha Steel Valves:
Inlet 0.15 ~ 0.20mm
Exhaust 0.25 ~ 0.30mm

Same bike with Yamaha Titanium Valves:
Inlet 0.10 ~ 0.15mm
Exhaust 0.20 ~ 0.25mm





Related Content

Reviews

Kawasaki KLX450R 2008 by ThumperTalk


Kawasaki KLX450R 2008
  • 9 reviews
  • Last review by neil-mx
  • On September 09, 2014
Reviews

Kawasaki KLX450R 2010 by ThumperTalk


Kawasaki KLX450R 2010
  • 0 reviews
Reviews

Kawasaki KLX450R 2012 by ThumperTalk


Kawasaki KLX450R 2012
  • 0 reviews
Forums
Photo

Photo of my KLX - let's see yours... by PigPenKLX450


Dirt Bike   Make / Model Specific   Kawasaki   KLX450R
  • Hot  495 replies
Forums
Photo

450 KLX intake camshaft surface by v55


Dirt Bike   Make / Model Specific   Kawasaki   KLX450R
  • 8 replies
 
x

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.