Just wondering what year it was that Honda addressed the valve issue with CRF450rs?  No I'm not trying to start a war or something.  I just thought they did something around 06 or 07 so you didn't have to adjust valves every 10-15 hours.  I've got a kid who's interested in a CRF450 but I'm the one that does the majority of maintenance around here so it's been Yamaha 4t and KTM 2t as of late.  Once again, not bashing just asking.

As a rule, w/ the first top end I got to Faction SS intakes and I never have problems from there on out. I don't have problems before then either, but I do run SS ins.

I had just heard they finally came out of denial and changed the design of the valves but can't recall what year it was.  Yeah, SS valves are definately not going to stretch like Ti ones, but are going to feel different as well.  If I can stick wtih Ti valves I will.

It was in '06 with an improved valve seat material.

they never had a problem on the 450rs.  

07 they went with a smaller exhaust valve for better low end.  06 they changed the valve seat material.  Otherwise it has always been Ti intake, SS exhaust from the factory.

You are probably thinking of the 04 250R bikes

Smaller valves are better all-around.  The 2007 change was a good one; for whatever reason.

FZ1426 said:

+ 1

My '05 had about 1/4" seat material missing on an exhaust valve. The coating on the TI valves wears off causing need for shim adjustments.

S.S. does not have this issue but they are heavier require stouter springs and do not rev as quickly.

I replaced with an '06 head and full Kibblewhite S.S. It is on a street sumo 450R. No adjustments and 500+ miles thus far.

my .02

From what I see, there wasn't as much of a 'valve' issue as the earler models (02, 03, 04) had issues with the air filter sealing.  Thus allowing some dirt past and 'sanding' off the coating on the valves.

JJRace said:

scientoothical said:

he's right.....the issue's in the past and present are due to operator error

crf-f crf-r trx cbr said:

Sure.

crf-f crf-r trx cbr said:

Do you work for Honda?

The reason I never bought an 02-05 Crf450R was because of all the posts here on TT by CRF owners pullin their hair out because of valve issues.  When I talked to the local Honda shop they blew me off with "what valve issues."  I started buying Yamahas in 02.  I still have one of my 02 YZ250Fs that I just did the first valve shim, which was still in spec, barely, after 6 years and over 300 hours of hard, fast paced trail & track riding.  I have owned Hondas since 1974.  That's a long time to be a Honda loyalist but switched to Yamis in 02.  Might consider trying a CRF if I could find a really clean used one for the right price.  But I've got to make sure their reliability is on par or better than what I've been riding.

The 07 heads with the smaller valves work better because of increased velocity.  

The 04 crf250r is the honda that had valve issues
the 02 450r had airbox sealing issues, but the whole motor and carb is going to get damage from that.  has nothing to do with the valve train.  

I am sure that most people do not change the valves and piston per the manufacturer's scheduled maintenance.  Yes it is a bit agressive, but it is what the manufacturer designed the engine to be reliable.  So you trail riders that put 100s of hours on top ends are way past the expected life time of the motor.  These are race bikes and thus have an increased maintenance schedule.  if you did not want that, then stay with a 2 stroke or the XR/CRF-F lineup of products.  

Not many engines on the planet can turn the HP and RPMs of the modern 4 stroke race bike and have a long life span.  They turn 2x your Chevy SB does or acura.  Only cars like the Ferraris can spin upwards of 9K, but look at their maintenance schedule!  It is not your $20k car that only needs a 100K tuneup.  

I see the original poster has had good luck with his Yamaha.  Great.  But the 06 YZ250f bikes were recalled due to valve issues.  I dont see you shying away from yamahas.  Keep that in mind.

JJRace said:

The 06 Yamis did have valve issues.  But Yamaha did a ASAP recall replacing all units free of charge.  They didn't deny the issue, they fixed it ASAP.  And not even all 06s had the issue, just certain vin's.  There's many aspects I like about the CRF line, that's why I'm reconsidering these bikes.  But they'er not superior in terms of the RPMs they turn or their race performance when compared to other mfgs, such as Yamaha, yet their maintenance seems higher with regard to top ends: ie, pistons, rings, valves, etc.  I enjoy working on bikes, but enjoy riding them even more. And I totally agree about maintenance being a must.  This is good info and I appreciate it.  I'll keep doing my research.

who says they fixed them?

they may be getting better, but they are far from as good as some other bikes.

I am meticulous with my 06 as far as maintenance goes... cleaning air filters and inspecting/adjusting valves... the valves on my bike started moving at around 75 hours and haven't stopped.  I've seen tons of other people on this forum with the same issues... doing top ends every year or every other year...

my previous yamaha's and current ktm needed few if any valve adjustments... same goes for my buddies yamahas and KTMs, all high hour, hard ridden, bikes, of all sizes.

I love my honda, it's my primary bike, but you can't deny the valves on these guys just don't last as long as the competition.

crf-f crf-r trx cbr said:

+1 along with both of these gentlemen,letting dirt through to the intakes sandblasts off the hardcoating.New stock valves and springs with a proper valve job by someone that knows what they are doing and probably new exhaust guides and a good stock air filter and nasty pain in the ass airfilter oil with proper cleaning= no "valve issues".cheers

160 some hours on my 09.  No valve movement.  I'm a firm believer in smaller valves along with clean oil and clean air filters.

The 09 Cr's seem to have better valves it's just the cranks that are failing now.

gruberyz said:

Haven't heard of that one yet.  Hopefully that doesn't ring true for me.  Although, I did have my cases apart a while back & everything looked fresh.