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first time valve clearance

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hi,

I am a man w/ 2 thumbs but I am going to attempt to measure valve clearance this weekend to save $100. Please let me know if I am on track or if I missed something. 2004 YZ 250f

1. Take tank off of bike.

2. Take off upper motor mount

3. Undo spark plug cap and then remove spark plug (do i need to do this?)

4. remove those 2 things on the lower side of crankcase and adjust engine to TDC by rotating counterclockwise until the stamped I lines up in window.

5. Take off valve cover (2 allen bolts) and make sure engine @ TDC (line up dots on horizontal cover)

6. Use feeler guages to check clearance.

7. reinstall crankcase cover. (Do I need to use a new gasket or utilize any type of sealant?)

how did I do? did i miss anything and any other pointers? thanks.

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Sounds pretty close. Since your gonna save money by not taking it to the shop, spend some of the saved money and buy a manual. Someone on here may be able to give you a free download. Every bike I buy I buy a manual. Have one for a yz450f if you need it, should be the same. Reason being if you have to change the shims your gonna want to know tq specs on cam holders.

Also before you remove spark plug; spray a cleaning agent down the spark plug hole and blow it out with compressed air. Should be a small hole on the side of the cyl head for that purpose. No need to feed your engine dirt.

If you have to adjust shims use mechanics wire, zip tie or something to hold your timing chain so it doesn't fall into the engine while cams are off. While at it be sure not to drop half moon shaped cam holders in the engine.

Hope this helps

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I have the manual, just double checking w/TT. Sometimes manual is useless and TT forum helped me greatly in jetting my bike and w/other questions I have had.

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yeah some time my manuals are great, other times not so great. so i go to tt and youtube. still worth their money though

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I don't think you have to pull the upper motor mount. However I had to make mine since it was lost when I bought the bike. One thing you will have to do when checking the exhaust is to pull the decompression weight out to check one of the valves (can't remember which one the decompression actuates right now). When I say out, I just mean to pull it in the direction centrifugal force would sling it to let the exhaust valve shut fully - not physically removing it. I don't pull the plug or really check TDC, I just turn the crank until the cam lobes are pointing 180* from the buckets. Clay

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Make sure when you check the left exhaust valve that the decompression pin is out of the way. Otherwise it may look like you have below spec clearance.

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You do not need to remove the head stays (motor mounts) but it does make removing the valve cover a little easier.

You do not need to remove the spark plug but you do remove the boot.

You do not remove the crankcase cover just the plugs so you do not need a crankcase gasket.

You do remove the valve cover but do not need a new gasket if you didn't f&$k the old one up.

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I know this may be stating the obvious, but here is what I do as well as the avove...

Remove the tank & seat. Give the frame and the area above the valve cover a good clean. Blow any dirt from the wiring loom and surrounding areas.

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swede as always you are a wealth of knowledg. thanks, hopefully I dont f it up this weekend.

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You'll want tapered feeler gauges too. If you are using standard, auto store feeler gauges, they will be too wide to get a good reading on the intake side.

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great idea i got from forums was once you have everything off and are ready to take valve cover off , wrap some clingwrap (plastic lunch wrap) around all the frame wiring looms above engine and secure with electrical tape to prevent any dirt falling into cam area. No matter how clean you get this area there will always be some dirt lodged in there!!

Bennyroo

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What aBout the breather hose and oil line, do they have to be disconnected? If u remove oil line would oil come out? Sorry for dumb ?'s

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You shouldn't have to remove any oil lines. There are two breathers on top of the valve cover and yes they will have to come off (very easy job) and no, oil will not come out if you pull them off

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What aBout the breather hose and oil line, do they have to be disconnected? If u remove oil line would oil come out? Sorry for dumb ?'s

breathers vent crankcase pressure and oil vapors, they migt have some oil on the inside of the breathers but your oil is sittin at the bottom of the engine not on the top.

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Finished up, easier than I thought. Valves were well within tolerances. 2 quick things, when should I check again? And everyone said no need To drain oil, when I unscrewed circle on crankcase (below tdc view circle) lost about 8 oz's of oil. Next time I will drain it.

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