what to do about valves

[c91x]

Ok so I'm getting my bike ready for this season so i'm replacing my top-end with a wiseco hi-comp piston .....My valves have always been in spec but since i'm going to be in the motor anyway ive been thinking of replacing them . I don't have a whole lot of money to through at this thing though . Now i'm assuming my valve seats are fine ..should i just buy new intake valves and springs ? leave em alone untill they do go out of spec ? buy new valves and spring intake and exhaust ? I know i don't have money for a new 06 head and all internals of the head ...ive really been thinking of just changing the itake since they seem to be the ones that go out of spec the most but then again it might be wise to get atleast one shim out my valves then replace when they go out of spec again ? plus that way i can save up and buy each part seperatly ...any opinions would be helpfull

[angrytim]

How many hours? Have you ever shimmed?

It wouldn't be a bad idea to put in new intake valves and springs, etc.

I wouldn't worry about the exhaust.

[Enterprise]

I believe most people with knowledge and experience in this area are recommending that, at a minimum, you re-cut the the seats and replace the valve guides when replacing the valves and springs. The problem is, by the time you do that you're within $100 of the cost of a brand new head, and there's at least some hope, that the new seats on the 06 head are going to improve valve train longevity and some are saying that the 06 head offers improved performance.

With respect to the hi-comp piston - there's nothing wrong with this mod, and you'll definitely notice the difference. However, for not that much more, you can go with the 270 kit and that has a much more dramatic impact on the engine's performance.

FWIW: I'm about to put on my third head and after two stabs at the stock valve train - with little success, I'm going to SS intakes and aftermarket springs (RHC).

[sealusion]

I'm going to SS intakes and aftermarket springs (RHC).

I did the same thing and it has been great! RHC (Ron) knows his stuff!

[c91x]

about 60-70hr's on it ...not sure because i didn't get my hour meter on it till after about 20hrs and no i've never shimmed them

[perrymx23]

Hey guys my buddy is doing his son 04. He has the 13.1 hi comp piston. Wants to go with the 1mm oversize valves and seats. Has anyone done this yet?? He owns a body shop and trades work with a machine shop, so the machining is no problem. Also is a kibble white dealer so he can get either set up for the valves.

[c91x]

So i'm thinking i'm just gonna rebuild the top end and leave the valves alone untill i have to shim once (unless inspection shows otherwise) ...now what i'm thinking is Pro Circuit valve springs and kibblewhite SS intake valves ? ...as anyone done this combo ? it would only be around 200 for parts "maybe a bit more for a gasket kit" ..but it soulds pretty good to me ...thanks

[c91x]

well it finally happend i tore in into the bike and my right intake was at .004 ...i know not at .000 but it's closing up so i just ordered PC spring and kibblewhite valves ...what do you guys think of this combo

[Ron Hamp]

Hey guys my buddy is doing his son 04. He has the 13.1 hi comp piston. Wants to go with the 1mm oversize valves and seats. Has anyone done this yet?? He owns a body shop and trades work with a machine shop, so the machining is no problem. Also is a kibble white dealer so he can get either set up for the valves.

theres no point in putting in the over size valves the crf already has large valves for its bore they may even sshroud more and lose some flow .