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YZFR6... ooodles of HP
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Valves are seating based on those numbers. De carbon and call it a day. Remember to keep the valves accurately marked to what guide they belong to.
 
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Discussion Starter · #22 ·
Alright guys, so FINALLY got time to start tearing into the engine. I figured I'd start with Valve check first. 4 of the exhaust values I couldn't get a single gauge under. The other 4 are well under the minimum spec. (.1, .18, .15, .20). The thing is I had this exact same issue 10k miles ago when I had my valves adjusted. The exhaust values were so tight I couldn't get gauges under them. I had the shop do the adjusting, but I can't imagine they'd screw up that bad to where the exhaust vales are this quickly this tight. There were several intake valves out of spec but most of them fell into the range but on the tight side (and very sporadic I should add).

I suppose my question is what is causing the exhaust valves to get so tight so quick. I'd hate to spend money on valve shims if there is a larger issue at hand.
 

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If you "had them adjusted" only 10k ago, I'd wonder whether whoever did it, actually adjusted them... or maybe adjusted them correctly?

Only possible factors that that would cause such rapid wear are constant high-RPM, poor lubrication and/or junk parts.

Checked mine at 50k (engine never having been opened) and didn't really have anything that needed to be done; particularly since you can't get 0.01 increment shims.
 

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Discussion Starter · #24 ·
If you "had them adjusted" only 10k ago, I'd wonder whether whoever did it, actually adjusted them... or maybe adjusted them correctly?

Only possible factors that that would cause such rapid wear are constant high-RPM, poor lubrication and/or junk parts.

Checked mine at 50k (engine never having been opened) and didn't really have anything that needed to be done; particularly since you can't get 0.01 increment shims.
I hope that is the case that he just didn't do it right. But for awhile afterwards the bike was running far better so I'd like to think he was somewhat competent. It wasn't a dealership shop either. I tried going there the first time and there is no way they adjusted my valves.

I spend little to no time in the high rpm range. I've never had it on the track either. Unless there is a clogged oil port somewhere, I am meticulous with my oil changes so the bike always has good clean oil. I wouldn't even know how to check for a clogged oil port. All engine parts are OEM to my knowledge.

It's got me worried that something else is wrong. I hear more cases like yours where people hardly ever have to adjust them unless they are tracking the bike. I'll be adjusting them myself this time and lets just pray that it really was just a case of incorrect adjustments the first time.
 

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Proper oil weight? (not too thin, not too heavy)

Won't hurt to check. You'll probably find it's in proper range though.

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BTW, engine not running, this is one of the best lubed cam assemblies I've cracked open.... not that I've cracked open many.
 

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YZFR6... ooodles of HP
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34psi? I swear my 2017 spec is 6psi at idle.
 

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I never did pay attention to the fact that the spec was in that screenshot. That's for the 2008 R6-S model. (2nd Gen not 3rd Gen)
 

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Discussion Starter · #30 ·
Need some expert opinions. So for the valves that were so tight no feeler gauge would fit under them, they already had the smallest shim size (150) according to the manual. The manual states the shim sizes should only go from 150 to 240. I feel adding say a 120 would not be a good idea if the spec min shim size is calculated based on stem length etc (my assumption). My fear is the Exhaust valves have to be in bad shape if they are this tight with the smallest shim.
 

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YZFR6... ooodles of HP
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Are you sure the cam was at the correct rotation when the feeler would not fit?
 

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YZFR6... ooodles of HP
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It sure sounds like the cam is 180 degrees out, thereby compressing the spring.
 

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Discussion Starter · #34 ·
Its not though. The timing is for sure correct and the lobes are pointing up and out. The cam can't be pressing the springs unless the lobes are pointing down into the valve bucket which they are not.

I'm in believe that the valves have been pounded into the valve seat over time and that is causing the zero tolerance. I just wanted to get some experts opinion and course of action. The cost of new valves, valve guides and the cost for a machine shop to do it all is way more then the bike is worth. If the valves have been beaten into the seats then it does not make sense to push on with smaller shims even if it gets me within spec. The heads coming off this weekend. I don't know if it will be obvious or not as to whether the valves and seats are shot due to the reasons above. The sad reality is the end game might just be to cut my loses and part the bike out. But I didn't want to get to that conclusion without getting others opinion.
 

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UR B-hind Da 8 Ball
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Sounds to me you are correct. It is probably worth taking it to an auto machine shop and seeing what they suggest. (Take the cams with the head). They may be able to resurface the seats, and mill the stems down to get it back to the correct valve height. That’s what was done in the old days. In this day and age, IDK if anyone does that, and what they would charge. It might be cheaper to get a good used head..... but then, I guess you’re rolling the dice on a used head.

Tough call.
 

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Discussion Starter · #36 ·
Sounds to me you are correct. It is probably worth taking it to an auto machine shop and seeing what they suggest. (Take the cams with the head). They may be able to resurface the seats, and mill the stems down to get it back to the correct valve height. That’s what was done in the old days. In this day and age, IDK if anyone does that, and what they would charge. It might be cheaper to get a good used head..... but then, I guess you’re rolling the dice on a used head.

Tough call.
Thanks 8ball. Ill try and find a worthy machine shop near me and see what they say, but i cant imagine it will be cheap either way. Yea i thought about a used head, hard to trust any ebay sales though. Im in a pickle. I cant imagine a summer without riding but dropping big bucks on a bike i planned on selling in the near future doesn't make much sense. Uggh.
 

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YZFR6... ooodles of HP
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Stem grinding is an option to get clearance.
 

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Any chance of a valve seat breaking up or falling out?
 

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YZFR6... ooodles of HP
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Since it is the physical aluminum of the head, It can mushroom beyond sealing and or ideal flow. But you get low compression when the thing is deformed too much. It's 3 or 5 angles to limit seat contact and maximize flow at various openings.
 

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UR B-hind Da 8 Ball
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Since it is the physical aluminum of the head, It can mushroom beyond sealing and or ideal flow. But you get low compression when the thing is deformed too much. It's 3 or 5 angles to limit seat contact and maximize flow at various openings.
The seats are actually hardened inserts pressed into the head, not the actual aluminum. They are replaceable at around $5 a piece (then you need someone that can press them in safely.

the big issue is once you are replacing seats, usually you’d replace valves, but they’re like $100 a piece! Then there’s the valve guides... and oh yeah, you really need to replace the guide seals. That makes parts, alone upwards of $2000....BEFORE you have someone lay hands on it to press in the seats and guides, seat the valves and ream the guides.

Flyers28, If it were me, I’d find a machine shop that would look at the head and determine if they could do a 3 angle grind on the seats and grind the stems, and replace the valve guide seals. It might cost $200-$300. But it would be better than chancing it on a used head and way cheaper than a 100% refurbishment. The main issue will be finding a shop that would be able to deal with such small valves. If you do happen to have a motorcycle race bike builder near you it might be worth getting a price from them, too. But I’d suspect it could be almost as costly as all the new parts.
 
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