Titanium or SS valves?

I just sent my head into the reconditioners because the left intake valve kept closing up to zero clearance, my bike is an 04 RMZ250.

I know everyone has been over this topic a thousand times but,

My question is what valves should I get? I'd like to get at least 120 hours out of my valves.

I'm thinking faction mx Stainless Steel Intake valves combined with stock exhaust valves because the 04 was said to have valve problems. Is this a good setup or should I go all stainless or all titanium? I thought the exhaust valves were more reliable than the intakes, so this way it would fix the problem and not be too expensive.

The engine reconditioner says that if the titanium valves are installed properly they should be fine, but I am not sure because of reading posts about valves on this site.

Also do SS valves require hardened buckets or not?

Please help

Thanks in advance.

Most will tell you SS last longer than titanium. I am in agreement with that. As you already probably know, SS is heavier than titanium and require a "stiffer" spring to go with them. Kibblewhite seems to be the choice. Either way go one way or the other, do not mix the two...

Question 1: why shouldn't I mix the two?

Question 2: Do I need hardened buckets for stainless valves or can I use stock?

Thanks

Can some one tell me if the exhausts are more reliable than the inlets, whether you need hardened buckets when running stainless, and how many hours you guys were getting out of the stock valves.

Thanks

Hardened buckets are not required for the stainless steel valves.

I have an '05 KX250F and got a little over 80 hours out of the stock valves.

The exhaust valves always last longer. They say it is due to less heat on the exhaust side. It is always recommended not to mix the Ti and SS. I don't know the technical reasons.

Hardened buckets are not required for the stainless steel valves.

I have an '05 KX250F and got a little over 80 hours out of the stock valves.

The exhaust valves always last longer. They say it is due to less heat on the exhaust side. It is always recommended not to mix the Ti and SS. I don't know the technical reasons.

Is it heat or contamination that causes the intake valves to go more quickly? They are both in the combustion chamber. I don't see why the exhaust valves would see more heat. Is there more surface area on the exhaust vavles? Are they bigger than the intakes? I have my son's bike torn down right now and am blanking out, but one or the other is bigger I'm sure...

I have heard the intake side has more heat because that is where the fuel enters, but I am not qualified to debate the issue. The intake valves are larger than the exhaust valves.

I have heard the intake side has more heat because that is where the fuel enters, but I am not qualified to debate the issue. The intake valves are larger than the exhaust valves.

Not trying to challenge or debate. And in my post above, I referrred to exhaust valves, when I meant intake.

Either way, it would be nice to hear from someone who knows why the intakes are the first to go.

ive heard its down to bad design of the head, they dont get cooled as well, but thats what i read not what i know to be true.

Does someone know the technical on why Ti and steel can't be mixed?

Also i've read alot about the buckets on these bikes breaking, would SS valves aggravate the problem,

how many here with SS valves use hardened buckets?

You can mix Ti and steel from IN to EX no problem, the CRF is stock this way (Ti intakes steel EX's).

There is much more heat on the ex side as the very hot exhaust gas exit's here.....

I have found the EX's to wear badly in the RMZ's. I have had to replace a couple head because the seats were pounded terribly. The intakes are no better....

If you're going stainless go with the Faction full kit. I'm sure their EX set up will be cheaper than Suzuki's and they are decent.

Your head reconditioner is correct, with a good seat, spring and installation the Ti lasts pretty good.

Make sure to select the springs for your valve application. As one poster said you will need stiffer springs to increase seat pressure to control the heavier stainless valves.

deffiently get stainless steel.

faction mx makes really good ones

Can anyone tell me whether the SS valves cause a perceptible drop in power? Honda will often do things for a reason, and I don't think they would suffer the awful PR these valves cost them without some tremendous advantage. But I'm replacing my TI valves in my CRF450x for the second time since '05 and I want to go with SS. Will I feel the difference as an advanced intermediate rider?

on a 450 i really doubt you will feel the difference in power, not heard of people saying they feel a drop even on a 250.

its not neccasarily a drop in power but more like slowing the rate of accelaration of the engine.......the valves and springs are heavier in a stainless setup and they make the engine rev slower.....in my killer race car engine i build we use ti intake and exhausts ti retainers and lighter spring for a given combination by almost 20 percent ......the engine will rev farther faster and with less likely hood of valve float

cars have a lot of valves however....i have not read of one person saying the bike revs slower with ss valves, i am not saying they do or down rev slower, its just that it doesnt seem to be a real world problem.

not too many peopel will be able to tell but if u do a rate of acceleration test on a dyno u can see the difference ......i use ti intake and inconel ex on our turbo cars,,,,,,the heavier stainless intake valves dont work well with 35lbs of boost and the valve spring cant control them effectively.....switchin to ti intakes was worth 200rwhp on our car ...the boost was actually habgin the intakes open..and wouldent let the engine run cleanto 9000 rpm

Going back to the earlier debate quickly, the inlet valves will wear quicker than the exhaust valves as they are larger in diameter. I'm no expert so am not sure exactly why this is, except that I understand that it is due in part to there being more sideways and circular movement in a larger valve than in a smaller valve. Anyone expand on this?

Anyway, this led to many people opting for SS valves on the inlet side as SS valves used here would be expected to wear out at roughly the same time as Ti valves used on the exhaust side. When i first started riding 4bangers i tried to get the mechanic rebuilding my head to replace the exhaust side with SS too, but he told me it was a waste as they were likely to far outlive the SS inlet valves anyway and i'd just make the bike slower to react (though had he seen me ride he'd probably not have not said that part!).

In other words opt for the SS on the Inlet side and Ti on the exhaust side. This is what most rebuild shops would naturally do anyway. Kibblewhite are probably the best, but most reputable rebuild shops will have an equally good source that is capable of 120hrs.

Hope this helps

I had an 04 with alot of time on it the first year. So that winter tore the engine down and went over it, found the seats to be worn on the intake bad. I decided to get a new head and run the kibblewhite valve set up. I read on here how good everyone says there stuff was so I tried it. 10 hours on the new head and it was junk, the intake valves beat the seats into the head. Ending up getting the head fixed put the stock stuff in and got bigger rads. Never had a valve problem after, sold the bike and the kid is still raceing it today. Its heat and no lube in the fuel that kills these valves, any brand bike.

Run 1/2 ounce of two stroke in your gas or klotz fuel lube or even heard Marves mystery oil works. I've been running it in my 07 for bout 75 hours or so and never adjusted the valves yet. Just did the top end and it was clean inside no wear or marks of anykind. Just talk to race car engine builders they all (at least the ones I talked to) use some kind of fuel lube.

I had an 04 with alot of time on it the first year. So that winter tore the engine down and went over it, found the seats to be worn on the intake bad. I decided to get a new head and run the kibblewhite valve set up. I read on here how good everyone says there stuff was so I tried it. 10 hours on the new head and it was junk, the intake valves beat the seats into the head. Ending up getting the head fixed put the stock stuff in and got bigger rads. Never had a valve problem after, sold the bike and the kid is still raceing it today. Its heat and no lube in the fuel that kills these valves, any brand bike.

Run 1/2 ounce of two stroke in your gas or klotz fuel lube or even heard Marves mystery oil works. I've been running it in my 07 for bout 75 hours or so and never adjusted the valves yet. Just did the top end and it was clean inside no wear or marks of anykind. Just talk to race car engine builders they all (at least the ones I talked to) use some kind of fuel lube.

How the hell is it that with a new head and top of the line valves someone could have such shitty results?? And then others have great results, some with stock, others with SS? Stupid 4-bangers :excuseme::confused: Also 343, with KW valve set up, you do mean you replaced the springs and all right?

I've never heard of running fuel lube, anyone else had luck with this. Sounds like something worth trying though.

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