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07 crf250r valves

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I'm building a bike for my buddy and his valves are shot. I Havnt shimmed them yet but one intake I can't get a filler gauge through and one exhaust I can get either a .02 or .03 through. I was going to shim them but figured they're on the way out so I guess I'll just get it right for him. I was wondering what's the cheapest route to go for new valve kits and should I just have a local machine ship cut the seats? I usually have fastheads do mine but he dosnt have that kind of money to spend if he dosnt have to. Appreciate in advance.

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kibblewhite int valve kit is a popular SS conversion.

 

http://www.ebay.com/itm/KPMI-SS-INTAKE-VALVE-SPRING-KIT-CRF250R-04-09-30-31200-/221332822863?

pt=Motorcycles_Parts_Accessories&hash=item338876db4f&vxp=mtr

 

There are a few other options that may even be alittle cheaper, check out ferrea intake valve kits on ebay or some guys use proX which are probably the cheapest kits.

 

If you want to go the cheapest route for seat cutting find someone with a seat cutter that is set up for that head and knows how, probably cost somewhere around $50-$60 to get a 3 angle cut.

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kibblewhite int valve kit is a popular SS conversion.

http://www.ebay.com/itm/KPMI-SS-INTAKE-VALVE-SPRING-KIT-CRF250R-04-09-30-31200-/221332822863?

pt=Motorcycles_Parts_Accessories&hash=item338876db4f&vxp=mtr

There are a few other options that may even be alittle cheaper, check out ferrea intake valve kits on ebay or some guys use proX which are probably the cheapest kits.

If you want to go the cheapest route for seat cutting find someone with a seat cutter that is set up for that head and knows how, probably cost somewhere around $50-$60 to get a 3 angle cut.

Three angle? Wouldn't it be two? One angle for the two intakes and the other for the two exhaust cuts?

The exhaust is off too, the right one seems to have closed up some so I figured I should probably replace all four valves. If I do the intake valves SS then I have to do the exhaust SS too right?

I watched a few YouTube videos and it dosnt seem that hard unless I'm missing somethin.. But then again you said three cuts and I'm missing that part already. Appreciate your input btw

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Diggla.three angle valve jobs means 3 diff angles cut to make smooth transition on the valve seat for better flow the way I understand it

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The oem exhaust valves are steel or ss already not ti so theyre not as expensive.

 

Yeah whatwentwrong has got it right with the three angles, the middle angle is the one that makes contact and seals with the face of the valve. The top and bottom help transition and are used to get the middle angle width in spec.  

 

The three angle valve seat cut is what you have when you buy a new head, but you can send a head out to places like fastheads and they can improve on that with a 5 angle seat cut improving the flow and performance from the head.  

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My first question would be this: how do the valve seats look? If they're good, a cheapie way to do it would be simply to lap in a new set of SS valves (and use the matching springs for those specific valves due to the difference in weight). If the seats are no good, then you'll need either a three angle seat job or a new cylinder head.

The heavier (than titanium) SS valves work great. The only sacrifice is a bit on the very top of the RPM scale because the increased mass won't move fast enough. So, if you're friend isn't on the rev limiter all the time, he'll be fine with stainless intakes.

Edited by techgreg

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I figured I should mention that stock intake valves on that bike are titanium. You can't lap titanium valves as you will wear off the coating and they will be ruined. Steel or SS valves can be lapped. The seat material Honda uses on the '07 is quite hard and if in good shape will take a lap job well.

Edited by techgreg

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I figured I should mention that stock intake valves on that bike are titanium. You can't lap titanium valves as you will wear off the coating and they will be ruined. Steel or SS valves can be lapped. The seat material Honda uses on the '07 is quite hard and if in good shape will take a lap job well.

This sounds good man. I plan to replace them with ss. I Havnt removed the head yet but I'll get back to ya on this

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Also when lapping, you use the new valves to "lap" twist in the seat? I've seen a few videos and it looks super easy.

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Just know that lapping valves on a worn seat doesnt ensure a good seal.

 

After a ti valve zero's out and has been re shimmed the valve seat has some deformation also, its just not as severe and obvious as the valve.

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Bigborethumpers.com you can get a valve job for $79.00 and a stainless steel valve kit for $210. And will come back to you fully assembled for that price. The only other thing it may need is valve guides, and that will run you an additional $140. Check it out. Or we have new heads ready to bolt on with our stainless steel valve kit installed for only $575. 

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