[thor_mx_22]

hey guys i am thinking about getting a 06 crf450r but i want to know more about maintenance. atm i have a 06 ktm 250sx i have only had it for about a month but i think a 4 stroke might be better for me. the guys at my local bike shop said that my sx would be alot cheaper to maintain because the crfs chew valves and something about tappet clearance. so could someone tell me what needs to be done and how often i would do all the work myself cause dad is a mechanic so he will help me. im am doing a bit of racing and i do alot of riding in the bush. do you think it would be cheaper than my sx. any help would be great
thanks tyson

[poway450]

I have an 06 450r. It is true that 450s chew valves but any 4 stroke does. Where it gets expensive is if you do not stay on top of checking your clearances. The book says to do it every 15 hrs and that is true. IT also says to replace the piston and pin at 15hs which is false, Just take the head off bout every 25 hours and look for piston slap. you said your dad is a mechanic so working on it will be easy. you can do a whole top end build for about 400 in parts and 150 or so for cutting the valve seats. That really only needs to be done about every 50 hrs depending on how hard you ride. My 06 has 21 hrs on it no problem. my only real peace of advice is buy new. it is more expensive but it is really easy to hide major problems on theses bikes when you buy used, and buy and install an hour meter makes maintance much easier.

[UteMachine]

Thor, there are three things that are a sure thing:

1. Death
2. Taxes
3. Talk to someone who doesn't know about CRF's and they will tell you they chew valves.

CRF's DO NOT chew valves any more than an RMZ, KXF, or YZF do. There are a number of factors that will contribute to premature valve wear. Lack of maintainance is right at the top of the list.

Basically you want to check your valves on a regular basis. As soon as they start to go out of spec, you shim them back into spec.

Here comes another myth I hear often about CRF's. "As soon as you shim them, you will need to replace the valves after one ride." Man have I gone the rounds on this subject at motoutah.com. Many CRFers have been able to shim the valves multiple times before replacing the valves.

Bottom line is a 4 stroke requires a little more maintainance than a 2 smoke. However, if you take care of your bike, it will take care of you. One last thing I will mention. With a good manual, a little knowledge of the wrench, a little support from your CRF brethren, you can do just about everything your CRF will require of you. Good luck!

[[email protected]]

Talk to someone who doesn't know about CRF's and they will tell you they chew valves.
CRF's DO NOT chew valves any more than an RMZ, KXF, or YZF do.

So true and excellent post period UteMachine.
Thor, everything he said in that post is right on the money.
Yamahas , if taken care of properly may last a little longer for valve replacement, but their freakin' parts prices are so high (plus you need one more of everything ) that though their valves MAY last 25-30% longer the price to do so is 40-50% more. The Honda is easier to work on than any of it's competitors as far as I'm concerned too, the single overhead cam/UniCam design is very simple compared to any DOHC design.
It is surprising to me but it is true that Hondas parts prices are cheaper than all the other brands for the most part. Doug

[thor_mx_22]

yeah ok thanks for all your help guys