Does valve clearance get tighter or looser?


19 replies to this topic
  • 06WR450FSM

Posted April 29, 2006 - 06:52 PM

#1

Just checked break-in valve clearance after ~12 hours.

Clearances look tight. Exhaust .007 guage fits easy. .008 guage a tight fit (should be .0079 to .0098). Intake can't get .005 to fit, don't have .004 (should be .0039 to .0058).

Do valve clearances usually get tighter or looser after break-in?

  • Yamaster

Posted April 29, 2006 - 06:56 PM

#2

It usually gets tighter from the valves beating into the seats more and more. I have almost 500 hours w/o needing a valve adjustment and that includes one trip to sandmountain and one long trip to pismo. She still fires quickly too.

  • 06WR450FSM

Posted April 29, 2006 - 07:31 PM

#3

It usually gets tighter from the valves beating into the seats more and more. I have almost 500 hours w/o needing a valve adjustment and that includes one trip to sandmountain and one long trip to pismo. She still fires quickly too.


What were your clearances after break-in and how much have they changed in 500 hours?

  • 642MX

Posted April 29, 2006 - 07:58 PM

#4

Valves almost always get tighter. :crazy:

  • 06WR450FSM

Posted April 29, 2006 - 08:30 PM

#5

Is it unusual for the valves to start out tight?

Do the shims come from the factory all the same thickness or does it vary from bike to bike (and valve to valve on the same bike)?

  • 642MX

Posted April 29, 2006 - 08:38 PM

#6

Is it unusual for the valves to start out tight?

Do the shims come from the factory all the same thickness or does it vary from bike to bike (and valve to valve on the same bike)?




The valves are shimmed at the factory, and usually on the loose side. It would be rare to see a tight valve from the factory. The size of the shim depends on each valve for each bike.

  • 06WR450FSM

Posted April 29, 2006 - 09:06 PM

#7

The valves are shimmed at the factory, and usually on the loose side. It would be rare to see a tight valve from the factory. The size of the shim depends on each valve for each bike.


Sucks to be me... Wonder why mine are tight? I will buy a better feeler guage set and check again. Tool suggestions? :crazy:

  • tmckeown

Posted April 29, 2006 - 10:05 PM

#8

Hi,

Just a normal feeler gauge which are used in cars. Should be found from a local automotive shop. When they assemble engine at the factory they use shims with different thikness. Mine has atleast 3 different thikness. My engine has 150 hours on it now and still no change on valve clearance.

Timo Mc

  • OneToGo

Posted April 30, 2006 - 12:46 AM

#9

Sucks to be me... Wonder why mine are tight? I will buy a better feeler guage set and check again. Tool suggestions? :ride:


Dont worry about it, I checked mine after breakin ( after a couple of hours) and they were on the tighter side of the middle of the range {similar readings to yours] - I felt the manufacturers would have set them up with a bit more space as well :ride: , but its a production line remember!

So, if they are in the range then OK. The important thing is to see how they change...I will probably check mine again after another 1500km just for mental insurance. If little or no change then OK (which I suspect will be the case!)
:crazy:

  • Matty05

Posted April 30, 2006 - 02:18 AM

#10

on the plus side, your motor makes more power the tighter the clearances get.

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  • OneToGo

Posted April 30, 2006 - 05:56 AM

#11

on the plus side, your motor makes more power the tighter the clearances get.


Thanks for that Matty, you learn something every day! More valve lift I guess?
:crazy:

  • MountainMax

Posted April 30, 2006 - 06:07 AM

#12

yeah, mee too, i'ts totally oposite compared to car engines who''s valve tolerances wear looser and have to be tightened up over time.

  • 06WR450FSM

Posted April 30, 2006 - 07:29 AM

#13

Hi,

Just a normal feeler gauge which are used in cars. Should be found from a local automotive shop.

Timo Mc


That's what I have now - with blades about 10 mm wide. I cut them length-wise to 5 mm wide and deburred the edges. .005 inch is my thinnest, so I may take the cut-off piece and try to grind it to .004. I think I saw some Pro Motion tappet feelers on the TT store that were thinner.

Just fishing for what tools others like...

  • mkporn

Posted April 30, 2006 - 08:29 AM

#14

That's what I have now - with blades about 10 mm wide. I cut them length-wise to 5 mm wide and deburred the edges. .005 inch is my thinnest, so I may take the cut-off piece and try to grind it to .004. I think I saw some Pro Motion tappet feelers on the TT store that were thinner.

Just fishing for what tools others like...



Just go buy a cheap set down at car quest or napa... :crazy:

  • 06WR450FSM

Posted April 30, 2006 - 09:49 AM

#15

Ground the leftover .005 piece to .004 (love that dremmel tool!) and will recheck the intakes. I hope it fits, don't want to reshim already...

  • MountainMax

Posted April 30, 2006 - 10:05 AM

#16

does anyone have a pic of what the shims look like? these thumper bikes are all new to me, I was a 2stroke guy all my life.

  • 642MX

Posted April 30, 2006 - 10:10 AM

#17

Ground the leftover .005 piece to .004 (love that dremmel tool!) and will recheck the intakes. I hope it fits, don't want to reshim already...




I custom trimmed my feeler guages to fit between the cam caps. Keep us updated.

  • 06WR450FSM

Posted April 30, 2006 - 06:11 PM

#18

Bummer - I had to grind closer to .003 to get it to fit under 2 of the intake valves.

Correct me if I am wrong, but tighter means that the valve edge has just seated a little more deeply into the head, so there is no actual risk of engine damage by a valve hitting a piston since the cam is pushing the valve the same inward distance it did when it left the factory?

  • Matty05

Posted May 01, 2006 - 03:27 AM

#19

Thanks for that Matty, you learn something every day! More valve lift I guess?
:crazy:

Exactly! :ride:

  • 06WR450FSM

Posted May 01, 2006 - 10:29 AM

#20

Bummer - I had to grind closer to .003 to get it to fit under 2 of the intake valves.

Correct me if I am wrong, but tighter means that the valve edge has just seated a little more deeply into the head, so there is no actual risk of engine damage by a valve hitting a piston since the cam is pushing the valve the same inward distance it did when it left the factory?


Some relevant discussion on valve clearance:

http://www.thumperta...d=1#post3328332




 
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