Should I get a new head?

[y2k_TA]

My new kw SS valves and springs just came in a few days ago and i am debating installing them on existing head or just getting a new head. a new head is only $240 from service honda. i just dont want to risk destroying new valves in the old head. the reason for replacing valves was .001 clearance then i reshimmed it started good for 2 weaks then back to .002 please help do i replace the head or not who else has done this and how is it working for you.

[YZFKIWI]

I have just been through this process, If you install new valves, springs etc you MUST have the valve seats recut.

I am pretty sure my problems were caused by replacement valves in to worn seats, I have yet to confirm this as i am only up to 3-4 hours on the Kibblewhite valves.

But I am pretty confident that is the (my) solution.

Regards

Marks

[MrBluefin]

My brother had similar situation with his 03 450. Valves went to zero, replaced w/ new Honda parts, springs seals, valves, the whole enchilada. Couple weeks later, clearances started decreasing again. Ordered new head and valves, been fine since. We later figured the valve seats in the original head were not cut correctly, the angles were not correct. We probably could have sent the head out and recut the seats, but opted just to replace the head.

[y2k_TA]

That is what I am trying to determine do i just get the seats recut and lap in the new valves or should i replace the head to be safe. if machine work is all i need thats great, i wont have to wait for parts to come in but if it is just delaying the inevitable i will get the new head and be done with it has anyone just done the recutting? how long did it last.

[711]

I've rebuilts lots and lots of engines and the seats can be recut to good as new condition. So its a waste of $ to buy a new head. Some bike shops have the tooling to recut valve seats. They are made by a company called Neway and they work great. Call around.

[Rich_Rohrich]

has anyone just done the recutting? how long did it last.

Every head that we replace valves on whether it's with the Kibblewhite stainless steel valves or OEM parts gets the seats recut. The only way you can be sure the the seat is the correct width, is concentric, and running square with the valve guide is to properly machine the seat and measure it. Once it's setup correctly the seats will last quite a while. There's no need to buy a new head unless you want a spare. Even with a new head we still recut the seats for the reasons I outlined above. ?

[spinyard]

So what is the correct way to cut the seats with a carbide tip cutter like the neway? 65 degree then 33 degree then 45 degree or something like that, It's been a while, but wouldn't mind having that neway tool in my bok for other valve seat cutting procedures...

[westladog]

I didn't replace the head on my 02 CRF450R. It was not a problem. It ran for almost two years before I sold it two months ago.

When i had the KW SS installed, the bike had about 150 hours.

[dsmolj]

I have my head cut on an crf250X a couple month ago cost was about $130.00

[dsmolj]

that also included the valve replacement and shimming,labor only ,I bought the parts

[711]

So what is the correct way to cut the seats with a carbide tip cutter like the neway? 65 degree then 33 degree then 45 degree or something like that, It's been a while, but wouldn't mind having that neway tool in my bok for other valve seat cutting procedures...

use the 45 first, that is the actual seating surface. You get a nice concentric 45 cut and narrow it with the 33 and/or the 65. You can also raise or lower the actual seating area with the 33 and 65. The neway stuff ain't cheap, there are different pilots for different engines, different cutters for different diameter valves, etc. I think the complete kit runs about $1500.00