Author Topic: Valve adjustment - more lessons learned  (Read 25598 times)

Offline holligl

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Re: Valve adjustment - more lessons learned
« Reply #75 on: December 30, 2017, 11:33:28 am »
Question #1: How far out of spec could valves be before problems develop?  If one were at the lower end of the spec (but still in spec), and the next check would be in ~26Kmi, normal wear might take them more significantly out of spec. 
Question #2: What is the worst out of spec you have seen, without adverse results?
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Offline SilverBullet

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Re: Valve adjustment - more lessons learned
« Reply #76 on: December 30, 2017, 12:14:42 pm »


...
Question #2: What is the worst out of spec you have seen, without adverse results?

Or asked another way...if no adverse conditions exist could the valve lash possibly be a problem?

A bike that starts, idles and runs flawlessly hot or cold; no extra noises or vibes; better mpg than new; no oil consumption; no overheating; no power loss; no hard starts; no fueling issues, etc.

Wouldn't something from above list start appearing long before valve lash was an issue?

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2011 Husqvarna TE630
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Offline Nikolajsen

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Re: Valve adjustment - more lessons learned
« Reply #77 on: December 30, 2017, 02:49:40 pm »
The worst that can happen is actually if the valve if to less in gap...
Then the valve will burn, and you might not feel anything before it is to late.
And when to less gap= no noise :mad:
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Offline Checkswrecks

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Re: Valve adjustment - more lessons learned
« Reply #78 on: December 30, 2017, 03:02:04 pm »
1.  The gap is specified to provide the tightest possible valve operation when the engine is hot and running. The valves stretch, the cylinder stretches a different amount, etc, and all these tolerances stack up. Then the engineers add some value for wear between checks. We as owners and maintainers don't have the engineering or test data to say specifically 0.XY" is the absolute limit.


2. It's also not really a question of how "out of spec" has anybody seen before becoming an issue, because there is a curve of time and use to balance against how tight the gap (or lack of) is. As the effective gap during operation (not what you set it to) is eliminated by wear, there will be a gradual leaking of the hot erosive exhaust gasses past the valve(s). If you normally ride fairly easy and with less revs than another person, the temperature and time for the valve and seat to heat will have less erosion than the other guy with the exact same gap. His will wear and erode faster and so his answer will be different than yours.


Clear as mud, right? If you are within the lower spec and don't constantly rev the engine hard, you [size=78%]ought[/size] to make it to the next check. But if you've already got the rocker cover off and are right near the limit, why push and risk it when you have the hard part done? 
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Offline holligl

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Re: Valve adjustment - more lessons learned
« Reply #79 on: December 30, 2017, 03:31:58 pm »



Clear as mud, right? If you are within the lower spec and don't constantly rev the engine hard, you [size=78%]ought[/size] to make it to the next check. But if you've already got the rocker cover off and are right near the limit, why push and risk it when you have the hard part done?

I had the check done by a dealer at 30k miles. One valve was about 13% from the lower spec so they buttoned it up. I try to ride hard enough to avoid both carbon deposits and speeding tickets!

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Offline markjenn

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Re: Valve adjustment - more lessons learned
« Reply #80 on: December 30, 2017, 05:06:07 pm »
You can overthink this.  Only Yamaha has any real data and their judgment is that a motor that is within spec at X miles will be safe to ride for X + 26K more miles before clearances are enough out of tolerance for there to be an engine longevity or reliability problem.  That doesn't mean each and every S10 will be absolutely safe to go this long, but it means the vast majority are safe and the cost of more frequent valve checks for the outliers isn't justified by the benefit to the majority.

For a screw-locknut bike with no shims (e.g., a BMW oilhead) fine-tuning valve clearance to the exact middle of the spec makes some sense, but for a shim-adjusted bike, I take the mfg at their word - if a valve is within spec, even at the upper/lower limit,  LEAVE IT ALONE, especially if they're all within spec and you can avoid the hassles (and opportunity for problems) with pulling and re-timing cams.  And if you are using Yamaha shims, "fine tuning" within the spec isn't really possible as the variation between shims is essentially the same as the tolerance.  You'd be adjusting from near the limit on one side to near the limit on the other which is pretty pointless.  (Many believe that the tight side of spec is "dangerous" and should avoided, but individual engines wear their valve trains differently and while tightening is somewhat more common that loosening, it's not always the case.)

Now a little heresy:  Given what a hassle valve adjustment is on the S10 and the general robustness of the engine, I think you can make a valid case just to take your chances and not bother with valve checks at all.  It's not ideal and you might get (literally) burned, but I'd bet the vast majority of bikes would make it through their useful lives without a problem.  And if you're not a good mechanic or don't have a good one to rely on, I also think you can make the case that the risk of screwing up the adjustment is higher than the risk of skipping it.

- Mark


Offline SilverBullet

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Re: Valve adjustment - more lessons learned
« Reply #81 on: December 30, 2017, 06:01:34 pm »
You can overthink this.  Only Yamaha has any real data and their judgment is that a motor that is within spec at X miles will be safe to ride for X + 26K more miles before clearances are enough out of tolerance for there to be an engine longevity or reliability problem.  That doesn't mean each and every S10 will be absolutely safe to go this long, but it means the vast majority are safe and the cost of more frequent valve checks for the outliers isn't justified by the benefit to the majority.

For a screw-locknut bike with no shims (e.g., a BMW oilhead) fine-tuning valve clearance to the exact middle of the spec makes some sense, but for a shim-adjusted bike, I take the mfg at their word - if a valve is within spec, even at the upper/lower limit,  LEAVE IT ALONE, especially if they're all within spec and you can avoid the hassles (and opportunity for problems) with pulling and re-timing cams.  And if you are using Yamaha shims, "fine tuning" within the spec isn't really possible as the variation between shims is essentially the same as the tolerance.  You'd be adjusting from near the limit on one side to near the limit on the other which is pretty pointless.  (Many believe that the tight side of spec is "dangerous" and should avoided, but individual engines wear their valve trains differently and while tightening is somewhat more common that loosening, it's not always the case.)

Now a little heresy:  Given what a hassle valve adjustment is on the S10 and the general robustness of the engine, I think you can make a valid case just to take your chances and not bother with valve checks at all.  It's not ideal and you might get (literally) burned, but I'd bet the vast majority of bikes would make it through their useful lives without a problem.  And if you're not a good mechanic or don't have a good one to rely on, I also think you can make the case that the risk of screwing up the adjustment is higher than the risk of skipping it.

- Mark
Need a "like" button for this post.

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2004 Suzuki DL650 V-Strom
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Online eemsreno

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Re: Valve adjustment - more lessons learned
« Reply #82 on: December 31, 2017, 08:30:56 am »

Now a little heresy:  Given what a hassle valve adjustment is on the S10 and the general robustness of the engine, I think you can make a valid case just to take your chances and not bother with valve checks at all.  It's not ideal and you might get (literally) burned, but I'd bet the vast majority of bikes would make it through their useful lives without a problem.  And if you're not a good mechanic or don't have a good one to rely on, I also think you can make the case that the risk of screwing up the adjustment is higher than the risk of skipping it.

- Mark

I agree 100% with this statement!
And it is starting to be proven to be true by a lot of self inflicted foul ups.

Offline SilverBullet

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Re: Valve adjustment - more lessons learned
« Reply #83 on: January 02, 2018, 05:24:51 am »
The worst that can happen is actually if the valve if to less in gap...
Then the valve will burn, and you might not feel anything before it is to late.
And when to less gap= no noise :mad:
Cold starts get difficult when this happens I believe.

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Offline Next

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Re: Valve adjustment - more lessons learned
« Reply #84 on: January 05, 2018, 08:47:12 am »
Hello all,

Just to add some user info.  I just bought a 2014 with 50k miles on the clock and decided to get the valves checked.  This was the bikes first valve adjustment and was performed by the dealer.
 
Results:  5 of the 8 valves had tightened past factory recommended tolerance (one exhaust valve was at .10, pretty tight) and the bike was running very well with no noticeable valve clatter when I brought it in.  It took the tech about 10 hours to adjust everything, throw some plugs in, and sync the throttle bodies... but they only charged me the 5.5 hours they quoted which was still close to $650 with new plugs, gaskets, taxes, etc. 

This is a service you only do a few times over the life of the bike.  For me, it's worth the money to let the dealer do it so I don't grenade the engine.  That said, I do just about everything else myself.  I will be pulling the forks for an oil change, bleeding the brakes and clutch, changing out brake pads, and greasing the rear swing arm and steering head bearing this weekend if the garage isn't too cold.  The only other thing I'll pay for is letting Touratech service the rear shock this winter.  They quoted me $100 plus shipping both ways to service one of their Explore units.  Money well spent in my book since it should make the thing good for another 40k miles.  I'll probably check the valves around that same time again... which will be a while. 

Don't know if this helps anybody, but thought I'd throw it into the mix.

Offline wfopete

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Re: Valve adjustment - more lessons learned
« Reply #85 on: January 05, 2018, 10:07:30 am »
I ain't touching my valves; just buying a new Tenere' when the time comes instead.
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Offline Bug Dr.

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Re: Valve adjustment - more lessons learned
« Reply #86 on: January 05, 2018, 10:35:28 am »
I ain't touching my valves; just buying a new Tenere' when the time comes instead.

That sounds reasonable to me since I'm on my second Tenere.  I live near Pete and I can't think of anyone that I would trust to check them in our area (maybe he knows of someone). I don't redline the motor but it does get ridden pretty hard at times on the twisty roads in the Ozarks though. Mostly, it is a big Swiss Army touring bike for me.
Mike

Offline wfopete

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Re: Valve adjustment - more lessons learned
« Reply #87 on: January 07, 2018, 07:21:39 pm »
That sounds reasonable to me since I'm on my second Tenere.  I live near Pete and I can't think of anyone that I would trust to check them in our area (maybe he knows of someone). I don't redline the motor but it does get ridden pretty hard at times on the twisty roads in the Ozarks though. Mostly, it is a big Swiss Army touring bike for me.
Mike

No suggestions.  I think one tech at our local Yamaha shop would do a reasonable job but they are under the hourly rate pressure.  I would consider meeting with the dude after biz hours and see if he would do the job on the side.  I would compensate him the full dealer labor cost for it...as long as I would get his best work.  But in reality, I would probably do it myself.  It might take a week and a bit of research on my part but in the end I would know what happened and who would be to blame for the success or failure of the work done.
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Offline tntmo

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Re: Valve adjustment - more lessons learned
« Reply #88 on: June 13, 2018, 12:31:49 am »
I did my valve check / adjustment today along with a manual CCT install.  My bike has a bit over 20k mile but I'm planning a long trip and just didn't want to worry about this while on the road.

I started at about 0900 and my friend came over about an hour after that.  I helped him change out both tires on his Africa Twin at some point in the day.  One exhaust valve was just below the minimum and one intake valve was a good amount over the maximum.  I can't recall ever having a loose valve before on any bike I've worked on.  I zip tied the chain to the cams and paint marked it, no issues.  After the job was done, I also swapped out both tires for a set of Mitas E-07 Dakars, checked all the spokes and swapped the rear brake pads. 

Not bad, even with beer breaks I was done about 1700.  I think just the valve check would take 4-5 hours going slow and methodical.

 

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