Smallest feeler won't fit under the intakes

[wielywilly-g]

My smallest size feeler guage is .0015" and will not fit between the valve caps and the intake cam. My goal is .006" gap. The stock shims were .095". Would you assume it was zero clearance and use a .089" shim to start with or assume it was .001" and start with a .090" shim? It was hard starting but ran fine when warm so I would imagine they were not at -.001" (or hanging open).

Please excuse me for working in inches instead of mm.

[Slackkinhard]

You're prolly only going to get one more ride before the gap closes...so I'd recommend getting some $ ready for some Stainless Intake valves. These things either stay in spec, or need work. I've never found a shim job to last long with TI valves.

[Johns08KLX450R]

a couple tips:

Make sure you check the clearance when motor is room temp

turn the engine over several times with a wrench to squeeze out any oil before checking clearance

you must have the piston at TDC COMPRESSION STROKE to check clearance. cam lobes will point away from each other.

Minimum clearance at room temp is .003" in my opinion

Measure again to be sure.

[wielywilly-g]

I would love to shell out some $ for SS intake valves, but I can't find a source for them. Yet anyway. I have only been looking for a couple days.

I am going to shim some clearance in them tonight and hopefully get 500 more miles before a headjob.

[Slackkinhard]

Yanni hooked me up with Kibblewhite who custom built me a set. Used my head as a template. So, I know they are retailing them now.

[Perry G.]

yep, i got 2000 miles out of my valves before they got out of spec, called kibblewhite got a set with heavier springs for around $200.00.

[wielywilly-g]

I got into it last night and had -.003" on the left and -.004 on the right. In other words the intakes were hanging open. I put .012" thinner shims in and now it is .009" on the left and .008 on the right. I know it is supposed to be .006" but I wanted to be on the loose side. It rattles some, but starts and runs perfect. That was a real pain making that cam chain tension holder plate.

I will call Kibbles. Thanks for the input.

[Johns08KLX450R]

Not good. How long do you think it ran without the valves seating? That is how you burn up valves, seats, and guides in a hurry. Hopefully you are still good to go.

Ive had good luck with the stock titanium valves. They are trick, but they are a lot more than $200 bucks! Stainless would be nice (since thats what the exhaust is), but do you have to use a different seat as well? At minimum a regrind would be necessary.

[klx450junkie]

Is this just a problem on the KLX as far as the titanium valves? My friend has owned Yzf and CRF's 4 stroke with titanium valves. He races rides tracks and desert. Currently he has an 06 CRF450 and has not adjusted his valves yet. He currently added a new pipe had it re jetted and had it on a dyno still no valve adjustment. I don't get it. Do the kx's have the same problem? I adjusted mine at 890 miles and all four were a little tight.

[Slackkinhard]

The biggest contributor is dirt gettin inside. Second contributor IMHO is the metallurgy isn't right. The choice of TI and the choice of seat material on the stock offering is suspect. The engineer down at Kibble noted it when he was designing the SS valve setup for me.

[klx450junkie]

The biggest contributor is dirt gettin inside. Second contributor IMHO is the metallurgy isn't right. The choice of TI and the choice of seat material on the stock offering is suspect. The engineer down at Kibble noted it when he was designing the SS valve setup for me.

So the KX,YZand CRF heads have ti valve seats?

[wielywilly-g]

Not good. How long do you think it ran without the valves seating? ...

I figure it was hard starting on 3-4 rides and I do about 35miles a ride avg 6mph. So 100 to 150 miles 18 to 24 hr. Most all tight windy and steep hills.

I am pretty anal with the air filter so dirt inside is not too likely. I did ride 6 hours on a real dusty day where I was following a lot and I had a patch of thick dust in one area on the Twin Air filter where it might have dried the oil and got through. It was hard to wash out with solvent.

I should find out this weekend if I ruined the head. Since the KX is more of a standard and more aftermarket companies offer SS intake kits for it, can I put a KX head on this bike? That would be nice.

Edited November 3, 2011 by wielywilly-g
photo

[Slackkinhard]

The airbox is a booger on this machine. Getting the filter on properly seated and locked down can be an exercise in confusion. Hard to be positive it's on becuz ya can't see, and my fingers don't fit well in there. The other problem is that the airbox itself has a seal on it where it meets the intake plenum that notoriously leaks. I siliconed mine together.

The seats are not TI, but the metal has to 'match' the TI coating characteristics. I'm no metallurgist, I'm just parroting what I was told by the one building the SS valves. He found it curious that they chose the compounds they did. My guess is the bean counters from finance got involved, added some creative license to the engineer's design, and ultimately the customer got what the bean counters gave us.

Yes, the KX head is a bolt on, IF ya get the whole thing...cams, etc. The E-start will require some Cam re-ramping from what I've heard.

[Johns08KLX450R]

My cylinder head on my 08 KX has done a LOT of duning. Dunes are the worst on machines, but especially the monsters in saint anthony. I rode there for an entire week (countless hours) at mostly WOT ripping huge dunes. Afterwards I wrenched the whole bike and the valves had not moved at all. So thats good enough for me!

[klx450junkie]

From what I here is staying off the rev limiter is a big help.

[wielywilly-g]

It is all good. Hit the trails for 5 hours Sunday and it held together. I tried to stay off the rev's a little more and use higher gear on hills with run-in. There was a little more snap in the low end and it started very easy when it was cold so I don't think I damaged the valve seats too bad. I will still get ready to do the top end work this winter with the help of Kibbles & Bits.

[klx450junkie]

It is all good. Hit the trails for 5 hours Sunday and it held together. I tried to stay off the rev's a little more and use higher gear on hills with run-in. There was a little more snap in the low end and it started very easy when it was cold so I don't think I damaged the valve seats too bad. I will still get ready to do the top end work this winter with the help of Kibbles & Bits.

Good to here, ride it hard.

[Johns08KLX450R]

yeah thats awesome its still running. Just looking at your pic, the cams look like they got pretty hot. Are they really that blue or is it just the pic? The bearing surface on the cams looks pitted too. The caps probably look the same? Not sure how much longer it will last like that, but not long would be my guess. That is classic damage from running with no valve clearance.

Good news is that a KX head is a direct bolt on and it will also give you a lot more top-end power. Look at the exhaust ports on a KLX vs KX 450 head and you will see why! The cams are interchangeable between heads but you need new cams anyway. Ive been real happy with the hotcams stage II in my KLX, but in hindsight I should have just spent a little more and bought an entire KX head with stock cams. KX has auto-decompression so I think it would work fine with electric start.