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Mileage of earliest valve adjustment???


v00d00child

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I had my valves checked at 28,000 km and they were well within spec. This is an expensive service in Vancouver [$340CAD incl tax]. Is there any sound or feel that indicates when they are too tight [i am assuming they get tighter as the shims wear]? I just hate to pay that much when I oculd go 100,000 km without adjustments needed. On the other hand, having a piston hit a valve doesn't thrill me either.

Any suggestions?

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I had my valves checked at 28,000 km and they were well within spec. This is an expensive service in Vancouver [$340CAD incl tax]. Is there any sound or feel that indicates when they are too tight [i am assuming they get tighter as the shims wear]? I just hate to pay that much when I oculd go 100,000 km without adjustments needed. On the other hand, having a piston hit a valve doesn't thrill me either.

Any suggestions?

Shims do not wear much, they are under a bucket. The bucket rides against the cam lobe. Even with my old 1100F with the shims on top did not wear much if any.

A tight valve will allow gases in the chamber to push back through the intake or exhaust at a time that they are not supposed to. Gas cutting of the valve or seats is the result....not much danger of valves and pistons colliding

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I had my valves checked at 28,000 km and they were well within spec. This is an expensive service in Vancouver [$340CAD incl tax]. Is there any sound or feel that indicates when they are too tight [i am assuming they get tighter as the shims wear]? I just hate to pay that much when I oculd go 100,000 km without adjustments needed. On the other hand, having a piston hit a valve doesn't thrill me either.

The valve adjustment in motorcycles that use shims usually get tighter, but not because of wear on the shims. It is because the valve itself tends to distort and "tulip". If they distort enough, they still won't hit the piston, but they will quit sealing properly, and you will loose compression.

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Guest rockmeupto125

Valve wear occurs on the face between the valve and the valve seat, where the metals meet to seal off the combustion chamber. As the valve and seat wear, the valve sinks deeper into the head when closed. This effectively lengthens the valve stem, and decreases the clearance. Once the clearance is zero, the valve starts to leak, allowing the flame and exhaust gas of combustion to flow past the valve edge, burning the valve.

That's why valves get tighter, not looser as they wear.

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That's why valves get tighter, not looser as they wear.

Valve lash is entirely dependent on what part of the valve trane is wearing.

Usually, it's the cam lobe & bucket which start to wear increasing the clearance in the valve trane requiring a larger shim to account for the wear.

Yes, if the valve seat were soft enough the valve would begin to wear into the head resulting in too little clearance as rockme stated. However, I thought it was only the early to mid 90's Kawi's that had a soft head issue?

Has anyone actually had to REDUCE the shim size on a bird?

Kev

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Has anyone actually had to REDUCE the shim size on a bird?

Yes. 3 of my valves were on the tight side @25K miles.

It is also highly unusual for the cam & bucket to wear before the face of the valve, and the valve seat, hence why valves tighten more often than loosen. Once a cam starts to wear, it's downhill fast as the hardening wears off.

Just ask the ZZR guys. :lol:

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Guest rockmeupto125
Valve lash is entirely dependent on what part of the valve trane is wearing.

Obviously, that idea makes sense.

But the part that most often wears is the valve and seat. Wear on the other valve train components is indicative of increased stress, poor oiling, or defective components, and as such, doesn't fall under "normal" wear. Valve/seat wear is normal, expected, and unavoidable.....that's why valves are made to be adjusted. Cam and follower wear may change the clearance, but as Chris said, that's a result of metal failure, not normal wear.

When I see the cam or shim wearing, I know there's a problem. And while I'm sure they exist, I've never taken a worn shim out of an engine. The cam lobes will grind into paste before then, once the hardening gives way.

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Has anyone actually had to REDUCE the shim size on a bird?

Yes. 3 of my valves were on the tight side @25K miles.

It is also highly unusual for the cam & bucket to wear before the face of the valve, and the valve seat, hence why valves tighten more often than loosen. Once a cam starts to wear, it's downhill fast as the hardening wears off.

Just ask the ZZR guys. :lol:

Really? So on the XX the shims actually have to be reduced to compensate for wear? Un"f***ing"beliveable!!!

Who was the engineer that decided to use a soft valve seat? I've been adjusting valves in the automotive trade for 15 years and never had to loosen one! The only instance I've ever heard of removing or reducing shims was on the ZX's & ZZR's.

So one can't even wait until thay start to tick, cause they won't if they're getting tight.

Kev

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You should check the valves every 3k mi and change the oil every 600.  Lube the chain after every ride.  Gotta go...haven't washed my hands in 10 MINUTES!!!!

You mean that's not normal? :wink:

Think I need to go wax the bike..it's been a few weeks :P

Rich

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I had mine checked at 50k:

All were OK, except one intake. Cylinder 4 aw reading at 10/11. Replaced 2.00 shims wiht 1.95 shim, now reads at 15/16  
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I checked mine at 27k when I had the head off.

Seats looked good, no sealing problems. In fact, I did not lap any of the valves in. I decarboned them all, but kept them in a tray so that the holes were filled with their same valves.

Springs, cams, lifters and lifter bores all looked good and within specs. All valves were slightly tight. A few of the exhausts were borderline out of spec, and one was out of spec.

Adjusted them all, since I had easy access.

J.

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  • 8 months later...

I checked mine at 27k when I had the head off.

Seats looked good, no sealing problems. In fact, I did not lap any of the valves in. I decarboned them all, but kept them in a tray so that the holes were filled with their same valves.

Springs, cams, lifters and lifter bores all looked good and within specs. All valves were slightly tight. A few of the exhausts were borderline out of spec, and one was out of spec.

Adjusted them all, since I had easy access.

J.

Wow, i'm REALLY impressed with what i'm seeing here. I had a Bandit 1200s, and those valves would get tight within 5,000 miles. Granted, the Bandit used a screw and locknut setup, but if the valves kept getting tight, then it was an issue of the valve face or valve seat wearing quickly. What kind of valves seats does Honda use on this bike? They must be tough as shit, because 25K and 50K miles with NO adjustments needed is almost unheard of on a high performance bike.

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Wow, i'm REALLY impressed with what i'm seeing here. I had a Bandit 1200s, and those valves would get tight within 5,000 miles. Granted, the Bandit used a screw and locknut setup, but if the valves kept getting tight, then it was an issue of the valve face or valve seat wearing quickly. What kind of valves seats does Honda use on this bike? They must be tough as shit, because 25K and 50K miles with NO adjustments needed is almost unheard of on a high performance bike.

Wow talk about digging a thread out from the past....

Not sure what they are using but with the exception of the CCT, stator and RR you'll find most things on the XX over engineered...

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