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04 Valves

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Hey guys I've got a tight intake valve. :bonk: it's JUST out of spec but I'm gonna shim it. I've read all the posts on how to do it, but still VERY scared.

Anyone have some pics of them doing it? Or any "watch outs" I should know about?

Thanks!

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https://thumpertalk.com/forum/showthread.php?t=461811

This is from the KX250F forum. Same bike as yours, just green instead of yellow.

He did an excellent job describing the procedure and with pictures.

AWESOME! Thanks...

Just got done checking them. I KNEW my bike was having a problem for a reason.

Intake are at .08 and .10

Exhaust are at .16 and .16

Damn... Intake moved .01 over 3 days and exhaust about .02

So should I just shim them to the loose side? like .13 or .14 and .20 .21 on the exhaust?

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If they're moving that fast it's probably time to replace them. It usually indicates you have worn through the coating that is on the titanium valves and if you shim you find they last a couple of hours and they need shimming again.

How many hours do have on your top end?

Each shim changes the gap by .025 mm, so if you go down one shim size on the .08 you will be at .105. If you shim I would go down two sizes on the .08 and down one size on the .10. That would put you at .13 and .125, in the middle of spec.

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Hmm I've got like 40 hrs on it now. *just a guess* but I've had it for over a year and they are just now getting out.

Is removing the top of the head hard? Was thinking of just sending it off to mxtime.com and getting all the work done for the $425. Good idea? Bad idea?

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I bought the Kibblewhite valves and valve springs then had the valve seats cut at my local dealer. Cost me about $475.00. They took the old valves out, cut the seats and put the valves in and shimmed them.

I called Mx Time and spoke to Dave. He is real helpful and if you send your cams with the head he will shim them for you. You have to pay shipping to get your head there and then he will pay the freight to send it back but if you want insurance (and you do!) you have to pay extra. I'm sure he does a great job.

I would try shimming first if you only have 40 hrs. on the bike. Getting the cylinder head off is not difficult.

http://www.nbsupercycle.com/servicemanuals/04servicemanuals.htm

Above is the link for the service manual if you have not gotten it yet.

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Yeah I gave them a call, Dave was very helpful!

I'm gonna shim them for now and get the head redone at the end of this month.

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Well the guy I was going to go to Moab with in 2 weeks just broke his leg...

So I'm going to be sending the head off to mx time.

Anyone have a picture tear down of how to get the head off? Or advice. I've had the service manual but the thing just scares me... Any help would be great! Esp if you live in the Denver, CO metro area.

Will I have to pull the motor to do all this, or just leave it in the bike.

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Well I decided to take a go at it...

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All n all wasn't too hard, just took a while but I had a lot of fun doing it. Now OFF with top to get new springs and valves.

P.S. Don't laugh at my bike stand... :bonk: It does a good job

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While your this far, piston and rings would be smart.

Rocky Mountain has the Wiseco piston, rings, pin and clips for $118.00

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http://www.rockymountainatv.com/productDetail.do?navType=type&navTitle=Engine&webTypeId=201&webCatId=17&vehicleType=&pageLinkUri=&prodFamilyId=3784

Above is the link to purchase the Wiseco piston and rings.

Honing these cylinders is somewhat controversial. The service manual says not to hone. I had mine lightly honed by my local shop to take the glaze off and restore the crosshatch. They did it when they re-cut the valve seats in my cylinder head at no extra cost. Thats one advantage of having a good relationship with your local shop. I also was able to buy the valves and springs and all the parts I needed through my dealer by shopping on line and asking him if he could match the pricing I found. For the most part he was able to come at least close.

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dont get them from rockymountain go on ebay right now a guy has two brand new wiseco kits for $90 shipped i bought one from him last week

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