Valve Adjust Procedure for YZ250F/YZ400F/426F/450F

nice man...looks like a pain to do that, 2-stroke don't have valves  

thanks twist for the awesome pic

My 2-stroke weed waker does.lol  
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I love this dirt stuff.

Why would a 2 stroke weedwacker need a valve?  

Bill H.
Temperance, Mi
2000 CR250R
1991 YZ125

Great post; deserved of Sticky Status for sure...  
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Dave H 2006 YZ250
(2008 YZ 125 son)

this spring im getting my 1st 4 stroke. before that ive only owned 2strokes but on the 2's i can do anything thats needs to be done. How hard are doing the valves compaired to working on a 2stroke.  

Guys, doing the valve ajustment is not hard and less work then doing a upper end on a 2-stroke.

Now if you had to do the valves and/or piston themselfs well now, thats alot more work and money.  
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i plan on checking my valve clearance and ive read the manual but i jsut want to double check that i dont need to drain the anitifreeze or oil.

also the manual worded it like this

"Clearance (stem to guide):

Intake:
.010mm ~ .037mm

Exaust:
.025mm ~ .052mm


this is what i go by for the valve clearance correct?  

You dont have to drain the anitifreeze or the oil.

If thats what your manual says then thats what you go by.

What bike are you doing?  
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thanks for this it is awsome  

I have to say this is a great write up on checking the valves!!! Kudos to you for doing it.  I do have to ask is it common to need different size shims when adjusting valves.  Found that mine were .03-.05 diffrence in adjustments?  

Yes, it is common. From the manufacture the shims come in any size to the .01, but they are only sold by .05. So it is not uncommon to find a 174 shim in there while a 175 would be the closest available to us.  

I got the shim kit from hot cams. Never have to go and get a shim, the kits come with 3 of every size.  
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Just remember TDC on the "compression stroke" is very important and also adjust the chain tensioner (back it off 2 release the pressure) prior to putting it back in the engine. Nice job on the procedure-great pics.  

I was set at tdc.  Got the valves set to spec.  went to the local dealer and bought the ones I needed rather then the whole kit.  Fired it up after kicking it a couple of times real slow to make sure nothing was bound up.  Reset the carb a little and she runs like a lion now.  No more pusssy cat here.  I wouldnt have attempted it by using the manual.  This write up saved me a few ***  if you know what i mean I cant thank you enough.  

TrackShark:
I was set at tdc.  Got the valves set to spec.  went to the local dealer and bought the ones I needed rather then the whole kit.  Fired it up after kicking it a couple of times real slow to make sure nothing was bound up.  Reset the carb a little and she runs like a lion now.  No more pusssy cat here.  I wouldnt have attempted it by using the manual.  This write up saved me a few ***  if you know what i mean I cant thank you enough.

Nice idea with the kicking it over. I generally du that with the spark plug out and then hit it with the fellers 1 more time just 2 make sure nuttin was binding. Also I can't imagine using all the shims in the Hot cams box. Buying only what u need is a money saver. What did a refill pack cost u?