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Have the intake valves changed (material) ?

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Hey,

I've been wondering if Honda has changed the intake valves on the 450R at all ? I've got an '05 that I just replaced the valve-train in this past August (with a Kibblewhite setup, original valves had 70 hours on them) and I'm thinking about getting my hands on an '08 at the end of this season.

I had an '02 before my '05 and I sold it to my brother-in-law in Dec. of '05. He had the piston replaced (routine maint.) last spring but didn't need to touch the valves. The '02 still runs like a charm. I guess my question is this, it seems to me that the late model 450's seem to have more of an issue with the intake valves than the older CRF's (I realize that how they are ridden and frequency are contributing factors) ?

I'd be surprised if Honda hasn't done something to correct the issue, having said that I just checked part #'s on the intake valves for the 2002 to 2006 CRF 450R's and they all have the same part number 14711-MEB-670.

Does anyone know if Honda has changed the intake valves at all in an effort to extend their life ? I've had 7 Honda dirt-bikes in the past 9 years, but if I know I'm going to have to replace the intake valves in 70 or 80 hours on an '08.. I may end up going with a blue bike.

By the way, a buddy that I race with has an '05 CRF 450 as well and had the exact same issue as mine within 8 to 10 hours of riding time. Another buddy has an '06 CRF 250 and had the same problem. If you are lucky enough to have gotten one of the CRF's that doesn't have the deteriorating valve issue, then good for you (I had one of them... my '02) but this is a real problem.

Thanks,

AL

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I know 07 changed the size of the intake valves, but not sure about the material.

Just checked my 07 after 10 hours, everything was pefect. After about 40 hours on my wifes 05 the intakes were .003 and .004, exhaust was dead on.

Chris

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02,03,04,and now a 07. no valve issues as of yet, i do set them up on the tight side after the first time out. may not have anything to do with it but like i said 4 bikes and no valve problems

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It all depends on how you ride the monster, and how you take care of it. I read a lot about valves going out in like 10 or 20 hours, but mine have lasted a hell of a lot longer than that. Then again, I am religious about maintenance.

You say that the blue bike might be more reliable, but the truth is that when a modern 4 stroke bike makes honda-like power (no matter what the color bike), it will more that likely have "valve issues." Just keep up on you mainenance and everything will be as good as it can be.

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I don't think my maintenance schedule (or my buddies) is an issue. I run ONLY Honda HP4 and HP4M fully synthetic oil in the tranny and crankcase. I've also got a Sendec hour meter on my bike and change both sides (and filter) at 7.5 or 8 hours of run time. My filter is done every third ride, or on an "as needed" basis.

The issue is the titanium intake valves. The exhaust valves are stainless, which is why they rarely require adjustment or replacement. The Kibblewhite intake valves are stainless, which is why they will last much longer than the stockers.

As far as I know Yamaha runs stainless intake valves in their 450, not titanium coated valves like our CRF's.

With Honda's reliability record, I wonder why the titanium intake valve ? 99% of the people that will end up with the 450 won't notice the power loss (I sure havn't) that a stainless intake valve would cause. And consider the trade-off...

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I thought the intake valves being titanium was to let the engine rev more freely, but I may very well may be wrong on that. I think that Honda uses the titanium more for the performance, than the reliability obviously. But I agree, 99% of everyone will not notice the change in performance with a stainless valve. I wish i rebuilt mine with stainless valves, but i could not afford it. Oh well, my stock stuff lasted 100+ hours, so hopefully the rebuild will too.

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I agree, I think Honda went with the titanium coated valve in order to gain a little performance. In a world where every little bit helps, I can understand their motivation. Having said that, I as a CRF owner sure would've appreciated a set of stainless intake valves to match the exhaust side. The minute amount of power it would have cost would not have persuaded me to buy another brand (I have yet to own anything other than a Honda). But, I don't want to have to spend another $400 (on my next bike) in order to "upgrade" my valves when in my opinion, they should have been stainless in the first place.

There's a reason why I (and most other Honda owners) have only owned Honda dirt bikes, their build quality is second to none. But I'm not made of money, and I won't spend another $400 replacing intake valves.

So..... having said all that..... does anyone know if Honda has changed their intake valves at all ? :applause:

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Honda didn't change the intake valves in 06, they changed the valve seat material to match the seats on the 05 450X's.

Apparently the valve seats on the older CRF's weren't as good as they could be, so Honda changed the seats on the 06 CRF-R's to increase valve life.

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I want some of you to consider one thing. The Honda has a single cam and four valves. The yami has two cams, 3 intakes and 2 exhaust valves. Naturally the Yamis are going to be less destructive to their valves because of this design. The Yamis are able to run a less aggressive cam profile because of the 3rd intake valve, allowing them to flow the same to through the intakes with a less aggressive cam because of the extra valve. Not only are there more intake valves, but because they are also smaller, making them lighter.

That said I have had an 05 CRF that never had any valves tighten up. Avoiding valve float is a key in increasing valve life. That translates into "shift the dang thing!".

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Apparently the valve seats on the older CRF's weren't as good as they could be, so Honda changed the seats on the 06 CRF-R's to increase valve life.

Thanks Kent, appreciate that !

Ok, so Yamaha has it figured out, now why wouldn't Honda run stainless valves all around ? I tend to think that if you have a hard material (valve seat) and a soft material (valve) that one of them is going to wear. Makes sense to me, but who knows... I could be wrong.

I'm 30, my buddy is 34 (with the other '05). Both of us run in the Intermediate class and have been riding for years, 15 for me. Neither of us want to be the next RC and we know where the bikes make power, where the limiter is, and where the power falls off.

I ran my bike on a dyno last year, here's an interesting piece of information : It made max. torque (35.9 ft/bls) at 7700 rpm, max. hp (50.3) at 8600 rpm and the limiter kicks in at about 10,250. I would guess that anyone who has ridden for a considerable amount of time would know the difference between 7500 rpm and 10,000. Knowing where the bike makes power (and where it doesn't) are big indicators of where it should be shifted into the next gear.

I think some people are missing my point. All I want to know is if Honda has changed the intake valves ? Oh, by the way.. Since I installed the Kibblewhites I've gone 43 hours and the valves have required zero adjustment.

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I know 07 changed the size of the intake valves, but not sure about the material.

Just checked my 07 after 10 hours, everything was pefect. After about 40 hours on my wifes 05 the intakes were .003 and .004, exhaust was dead on.

Chris

i think they changed the size of the exhaust valves not the intake and im pretty sure the valve seats are the only thing that has had a matierial change

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Thanks for the help guys. I'd assume that the seat material change will make a difference in how long the stock valves will last, regardless of type of use or someone's personal maintenance schedule.

So, this year has a different seat material than the '06 ?

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Thanks for the help guys. I'd assume that the seat material change will make a difference in how long the stock valves will last, regardless of type of use or someone's personal maintenance schedule.

So, this year has a different seat material than the '06 ?

Which year are you referring to? I believe that the 06 and 07 have the same valve seat material, just that the 07 went to 1mm smaller valves.

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SHIFT SHIFT SHIFT. Thank you. honda went with ti because of the cooling properties. Stainless is not as strong but does handle strectching. Ti doesn't handle stretching well. If you run against the rev limiter STOP. You hear the pro's hitting a limiter every start,turn and jump why? they have $$$$. Plus there mechanics turn down the limter rpm so hitting the redline doesn't have the exploding effect of stock redline. I have a 03 crf450r .:lol: I have my head off every 25hrs of riding and I have never had to adjust my valves yet. I ride c class 30 above(have to work on monday) I can keep up with a A rider but my wife won't let me race. you know mortgage and all. It comes down to don't hit the redline and everything will be fine. Shift the damn thing and forget your two stroke ways.:applause: As far as reliable keep the maintenace schedule according to your riding style and any color of bike is great.

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