[02450rider]

i have a 2002 crf450 had the zero valve clearence iam going with a whole kibble white setup the ss black diamonds and bibble springs what i need to know is do i need to have my head cut or anything machined if the old valves didnt damage anything or will the new ones just fit right in ??? plz help

[Aussiecrf230]

It is a 2002 so it is long overdue.
Yes you may have to replace guide and machine seats.
Depending on what needs to be done, it may be better value to start with a brand new latter model head.
CRFs Only do provide a trusted service and I am sure Ken can give you some ideas and pricing. The other question to ask yourself is what condition is the bottom end in. Might be worth giving the whole bike a freshen up.

[02450rider]

its not still stock and its been well taken care of b4 also the bottom was done not to long ago i bought the bike from a buddy he had the stage one hotcam installed he took the bike in around november to our honda shop and had them do new valve guides and seals, chain tensiner all that but they only shimmed the old valves instead of replaceing them so iam just doing what i gotta to get it up and running right now gunna goto a 06 later, but i just wanna get back out so ordered the ss blackdiamond kit with springs piston and rings are in great shape still and jug looks great already put in like 400 in parts so hopefully if i have to machine the seats it wont b to much more

[crfsonly]

when replacing worn valves you do need to have the seats professionally cut or you will significantly reduce valve durability. we offer these services as mentioned. as well we provide new heads with our CNC performance valve seat and port bowl blending. in both cases we can outfit them with any valves you specify. however, for maximum valve durability i highly recommend the kibblewhite stainless valves.

Here's a link to our Performance CNC valve job with KW valve package:

http://www.crfsonly.com/catalog/product ... ts_id/3974

New heads here:

http://www.crfsonly.com/catalog/product ... ts_id/3167

the advantage of a new head is improved porting and valve seat material. oh, and all new seats and guides.

let me know if i can help further.

Ken

[02450rider]

Thanks for all the info yeah i already got the black diamond kit with springs and everything iam in prescott az i have our machine shop doing the work right now he only charged me 50 bucks in its only takening a day so ill have everything ready to go back together this weekend my buddys the main tech at our honda shop so hes shiming the valves and doing all the timeing for me so i dont gotta get my hands to dirty anymore just put the vlaves in and start the assemble

[02450rider]

ok i kinda got mixed up what valve springs are bigger the exhaust or intake iam pretty sure intake but i wanna make sure as i already took stuff out of the bags and got the springs mixed up need help asap plz

[kowski]

I just had the local honda shop install kimbal white intake valves into my 2009 450x head, I have reinstalled the head (myself) and very particular/careful with the timing. I feel very good that I have/had the timinmg done correctly, before putting the valve cover back on I cycled the engine through 5-6 strokes with the kick starter and then checked the timing again and everything looked great. I put the valve cover back on and then cycled the engine through 8 -10 cycles with the kick starter (pretty easy kicks just to make sure everything 'felt good'). I then gave it two harder kicks and then the kick starter gets 'locked' I cannot push it down any further. on the second kick I could hear a difference (like the intake stroke was not pulling in air). I took the valve cover back off, I cannot get the piston to TDC even by rotating the engine the other direction. I thought the maybe it was something in the cam that was binding. I took the cam assy off and still could not get the piston to TDC. I put as much slack in the timing chain as possible and finally was able to get the piston to TDC..... I have done all of these steps twice and the bike is on the stand in the garage bound up.... is there some timing chain guide the I cannot see that might be causing it bind some how somewhere?

[crfsonly]

are all shims present and accounted for?

[kowski]

yes all shins are accounted for... before installing the valve cover I checked the valve gaps (for record keeping). both times the engine has 'cycled' okay by using my hand and lightly with my foot, however when I give it a little more power on the kick its 'binds'

[crfsonly]

be absolutely confident you have each and every shim accounted for. i've seen a lot of damage caused by a shim lost in the motor.

you'll have to absolutely determine what is causing the engine to bind. if there was any engine damage specify what caused the damage and what parts were damaged. if engine was not damaged you'll have to inspect each component that moves when the piston cycles. i would start by verifying the cam chain tension system is fully functional and no part of it is damaged. if that checks out move to the flywheel and verify there's not an issue there. keep in mind it is magnetic so ferrous items will stick to it front side and back side. check the sprocket teeth, flywheel nut is torqued correctly, and nothing is obstructing it from rotating. check the clutch and kickstart systems.

then up top, check the cam, valve stack, shim buckets, etc.

this is a must find beyond a doubt what is causing this before attempting to start the motor.