06 have crappy valves like 04/05s?

[N300exJ]

Ive had my 05 450r for 8 months now and its time to do a valve job. Kinda sucks that this is like one of the only weak points of this engine. I was wondering if 06 450r's or crf's for that matter have better valves to fix the stretching problem of 04/05 450r's. OR did honda come out with better valves to fix the problem. Any info would be great. Id like to find a permenant fix for this.

8 months is really a pretty long time if you ride really hard

[motox450]

when you mean valve job are you replacing valves, valve seats, springs reatainers, and springs, or do you mean just reshimming the valves. If you waited 8 months to do any type of valve maint. then it is no surprise that you have to do an entire valve job. I check my valve clearances about every 4-5 rides. and I have had to reshim once in the year I have had my quad. I still have plenty of adjustment. The problem is once a valve goes tight if you don't correct it fairly soon it just makes the problem exponetionally worse. Once you do your first reshiming it doesn't take long at all, and isn't hard at all. In fact it takes me far longer to take my plastic off now then it does to get the engine apart and reshim it. Really the 450r motor is very mechanic friendly. This is just my .02

[Phills450r]

i have had my 450 for a year and 6 months now and never had motor problems :)

[N300exJ]

I have a shim kit and i have shimmed it once already. Did that when i put in my HRC kit. It was only a thousandth off. That was two months ago. I do ride it alot. And its already gettin harder to start and doesnt like idling all the time. Maybe something else is wrong? I do keep up on oil changes, cleaning the air filter(its dusty here gotta do it all the time) and checking the spark plug. Any other suggestions?

[Ralph]

what are your sources for saying that all 04/05 450r's have a problem related to the valves and make it a weak point?

[R3Concepts]

The 04/05s have bad valves? Huh. News to me.

[cals400ex]

i would check the valves now and see where they are at. also check the decompressor.

[DirtDevilBT]

The only weak valves are the intakes, the exhaust ones go through a much stronger harding process. When I did my p&p and springs, the intakes had cupped and needed to be replaced. I was only able to get KW intakes in stock size, they didn't have exhausts. I didn't check my valves for the entire 80 or so hours before tear down, my fault I guess o well. With the springs, you will want to go better valves at the same time, have to eventually

[N300exJ]

Yup it is the intake valves that are the weak link in a 450r's top end. Suprised some of you didnt know that. A friend of mine that works at a local dirtbike shop(He went to MMI so he knows his stuff) told me the OEM honda valves last the longest and to stick with them. Aftermarket ones arent as good. Well see though im gonna take it apart and see if they need to be shimmed again.

[motox450]

Tell your friend from MMI he doesn't know his crap. Kibblewhite makes SS valves that last far longer than stock valves. The valve train problems were more prominent in the earlier versions of the crf dirtbikes(02-04). I know I owned an 02 and had Eric Gorr from Forward Motion put in SS valves and it made a world of difference. In fact after the Kibblewhites where installed I didin't have to reshim ever again and thats with a year and a half of riding on them. So there are other valve makers out there that make a quality product that will outlast stock honda valves. It is actually the valve seat being to hard that eats out the titanium valves on crf engines and the SS Kibblewhite valves correct the problem. (Honda changed the valve seat material on later models to address the issue.) The stock TRX intake valves are SS and are not as prone to being eaten out(wear on the surface where the valve and valve seat hit). If regular maintance is done valve issues are not an issue.