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I'm fixing to rebuild the topend on my '05 CRF 250R. I'm going to put an '08 oem cam in it. I am wanting some advise on what valves and piston to put in it ( I was thinking about '08 piston and kibblewhite valves and springs? But I don't know if I should go with a oem '08 piston or aftermarket ?) All advise and comments welcomed. Thanks

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I'm fixing to rebuild the topend on my '05 CRF 250R. I'm going to put an '08 oem cam in it. I am wanting some advise on what valves and piston to put in it ( I was thinking about '08 piston and kibblewhite valves and springs? But I don't know if I should go with a oem '08 piston or aftermarket ?) All advise and comments welcomed. Thanks

What type of riding do you do?

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13:5/1 compression piston. its cool

Should I go with high compressing 13.5:1 for '05 or a '08 oem piston it has a higher compression than a '05 stock

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get a JE/CP/Wiseco/Cosworth 13.5:1 piston.. forged to tighter clearances then stock, more reliable and longer lasting.. only problem ive found with these pistons is you must check the ring end gap, ive had a few that are two tight..

for the valves- if your racing I would get oem, lighter and better then SS in racing applications imo, I ran Kibbles in my 05 and found that they beat the crap out of my seats and lasted just as long as my oem ones did.. another thing if you have the money and is a great mod for the 05 is to stick a stock 07 head/08 cam or a modded 09 head/08 cam on it, really wakes it up and brings its potential out..

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1: do I have to run different gas with higher compression piston?

2: will I have to change jetting?

3: I can go with the 08 cam without changing the head right?

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get a JE/CP/Wiseco/Cosworth 13.5:1 piston.. forged to tighter clearances then stock, more reliable and longer lasting.. only problem ive found with these pistons is you must check the ring end gap, ive had a few that are two tight..

for the valves- if your racing I would get oem, lighter and better then SS in racing applications imo, I ran Kibbles in my 05 and found that they beat the crap out of my seats and lasted just as long as my oem ones did.. another thing if you have the money and is a great mod for the 05 is to stick a stock 07 head/08 cam or a modded 09 head/08 cam on it, really wakes it up and brings its potential out..

I can go with the 08 cam without changing the head right? Will I have to change jetting or fuel( I run premium pump gas now) with 13.5:1?

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13:5-1 compression works great with 91-93 gas, its what I run with my JE. I did not have to change my jetting with the increase in compression. And you can use the 08 cam, not positive if you will have to change the springs, I think you might..

oh and if you think about it.. 13:5;1 compression isnt really even that much. for example my 06 had 12:9:1 compression stock. the 09-10 250's come with 13:2:1 I beleive, so they are increasing the compression a little, so by getting the 13/5 its a little better. you will feel better response and it will waken up the power!

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Ya Im goingbto see if I need to change the springs with the 08 cam I might just put oem 08 valves and springs in it

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the 08 cam requires 08/09 intake valve springs.. 04-09 use the same intake valves.. 08-09 use different valves then previous years and will not fit with your head

so for you to do the 08 cam just get your normal valves and exhaust springs, but get 08/09 intake springs, also with a new cam break it in with new lifters (buckets)

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the 08 cam requires 08/09 intake valve springs.. 04-09 use the same intake valves.. 08-09 use different valves then previous years and will not fit with your head

so for you to do the 08 cam just get your normal valves and exhaust springs, but get 08/09 intake springs, also with a new cam break it in with new lifters (buckets)

Ok, would the lifters be required or can I keep my stock 05 lifters? What will it do changing them?what if I get Ron Hamp valves and springs for my bike ( im going to see which is cheaper oem or Ron Hamps)

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the 08 cam requires 08/09 intake valve springs.. 04-09 use the same intake valves.. QUOTE]

Why does the '08 cam require the '08/09 intake springs, the valve weight is the same?

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The 08 cam is more aggresive then his 06 or 07 cam was, so different springs to work with the cam are needed, a little stiffer

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The 08 cam is more aggresive then his 06 or 07 cam was, so different springs to work with the cam are needed, a little stiffer

My bike is an '05

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