Valve Checks vs. Adjustment Required Poll

[TriggerT]

Did my first check this last winter at 35K miles. All within spec, with only one being every so slightly loose. Otherwise they were all dead on.

 

[FJRBluesman]

Shop did it both times, no shims required each time.... That kind of concerns me... :blink:

 

[Fred W]

Current poll standings shows you are by far in the majority.

The percentage of valve checks that did NOT need any shims changed:

On the first check is 81% , and the second check is 79%.

 

[HaulinAshe]

Hey Fred,

I need options for the 3rd, 4th and 5th valve checks.

 

[Fred W]

QUOTE (HaulinAshe @ Sep 14 2010, 10:19 AM) <{POST_SNAPBACK}>
Hey Fred,

I need options for the 3rd, 4th and 5th valve checks.

You got it, Bubba!! Now go vote!!

 

[FJRBluesman]

Current poll standings shows you are by far in the majority. The percentage of valve checks that did NOT need any shims changed:

On the first check is 81% , and the second check is 79%.

You're right. I forgot to exclude the last option of each. Thanks.

Hey Fred,I need options for the 3rd, 4th and 5th valve checks.

You got it, Bubba!! No go vote!!

Cool. It might be in 2012 when I can get the next one done.
Thanks Fred, excellent topic.

 

[Duster19]

Tried to vote but got an error message.

Anyways here was my vote...

I paid a shop to do it and they did not have to adjust (change) any shims

 

[BanjoBoy]

I dun checked 'em last night with over 27,000 and they're all perfect 7s & 8s. :thumbsupsmileyanim: I'll have to button her back up this morn'in. (Hope I can remember where all them parts go?)

 

[RaYzerman19]

The most interesting statistic:

Of the checks done by dealers, adjustment was required <i>only 18%</i> of the time.

Conversely, of the checks done by owners, adjustment was determined to be required <i>37% of the time</i>.

Conclusions: Both numbers of required re-shims are low, but you might conclude that, either the owners doing their own checks are more fastidious about it (false negatives occurring at the dealers), or the owners don't know what they are doing and incorrectly re-shim when it's not really needed (false positives in their tests).

Fred, just saw this, and the data is very interesting to me. Thanks for putting it together.

It might mean something, it might not. But I would think owners are not constrained by time like shop mechanics are. Also, there is lots of gauge R&R error and variables with feeler gauges, and owner's might be double-checking (I would roll the engine over again and re-check, just me being anal). And, it might be easier to think a gap is bigger rather than smaller. Very dependent on the skill and care of the individual.

 

[Fred W]

Also, there is lots of gauge R&R error and variables with feeler gauges, and owner's might be double-checking (I would roll the engine over again and re-check, just me being anal). And, it might be easier to think a gap is bigger rather than smaller. Very dependent on the skill and care of the individual.

I agree. There's a reason they call them "feeler" gauges, and it's called that because of the subjectivity of having to "feel" what a particular gap is like. That said, I would also agree that the primary error when using feeler gauges is to (incorrectly) gauge the gap larger than it actually is. Since valves really only wear where they become tighter, this would result in not re-shimming a gap that is actually tighter than spec. So neophyte feeler gauge users should err that way.

So who do we expect would make more errors using feeler gauges? If we can believe the stats (and I seldom do, at face value) they suggest that the DIY owners are somehow more adept at using feeler gauges than the shop pros are. :blink: I find that theory a bit hard to swallow.

Another hypothesis is that the shop pros will find a gap that is fractionally out of spec (too tight by a thousandth) and consciously decide not to do the re-shim, knowing that this it is not a dire situation for the engine, and that there is a relatively larger probability of engine problems after the invasive cam removal, as compared to leaving it alone.

OTOH, an anally retentive owner/ wrencher (like most of us) will go in and reshim whenever he finds a single valve that is just below spec by a thousandth. Hey specs are specs right? So you have to do it!!

So who is right?

[devil's advocate]

Let me put it this way:

Compare the number of times a re-shim is done (incorrectly) and it results in engine issues (either minor, correctable running issues, or massive engine damage) with the number of engines that have had issues of any kind due to overly worn valves.

[/devil's advocate]

 

[mattster31]

Crap, you guys are making me doubt myself here!! I just went through a shim check and all but 3 were over (on the tight side) the 3 in question were right on the upper limit. I always thought you re-shim to the "loose side" as valves will wear in the seat and thus will result in a tighter limit as the valve lifts in the shaft. Am I wrong here?? or have I just ordered all the wrong shims?? Good thing I haven't actually buttoned it back up yet.

HELP????

 

[road runner]

Did my first check @ 44000 miles and no adjustment needed. I do have 2 intakes on the tight side, but still in spec. @ .006", .007", .006" , .0065" . The .0065 is a loose .006 and a tight .007 so I split the difference. My ex. have 1 on the tight side, but still in spec. @ .008" , .009" , .0095" , .0075"

I may have some shimming to do this time next year.

 

[RaYzerman19]

Crap, you guys are making me doubt myself here!! I just went through a shim check and all but 3 were over (on the tight side) the 3 in question were right on the upper limit. I always thought you re-shim to the "loose side" as valves will wear in the seat and thus will result in a tighter limit as the valve lifts in the shaft. Am I wrong here?? or have I just ordered all the wrong shims?? Good thing I haven't actually buttoned it back up yet.

HELP????

We'll have to discuss more with Fred. I would have thought the common error would be to call a gap too small, as it should be harder to put a "too big" feeler in. That's why I would re-spin the engine over and remeasure... in case the gap grew... other things come into play too if you don't stop in the same position or things seat differently on the second spin.. I don't worry about a thou. but I like to look for repeatability in the reading I got. Spin a third time if need be (notice how my way will take longer!!). I would re-shim to the loose side also, as the gaps should be tighter with wear.

Thoughts Fred or did I misinterpret?

 

[Zorlac]

Also, there is lots of gauge R&R error and variables with feeler gauges, and owner's might be double-checking (I would roll the engine over again and re-check, just me being anal). And, it might be easier to think a gap is bigger rather than smaller. Very dependent on the skill and care of the individual.

[devil's advocate]

Let me put it this way:

Compare the number of times a re-shim is done (incorrectly) and it results in engine issues (either minor, correctable running issues, or massive engine damage) with the number of engines that have had issues of any kind due to overly worn valves.

[/devil's advocate]

https://www.fjrforum.com/forum//index.php?showtopic=130091&view=findpost&p=756344

 

[Fred W]

Crap, you guys are making me doubt myself here!! I just went through a shim check and all but 3 were over (on the tight side) the 3 in question were right on the upper limit. I always thought you re-shim to the "loose side" as valves will wear in the seat and thus will result in a tighter limit as the valve lifts in the shaft. Am I wrong here?? or have I just ordered all the wrong shims?? Good thing I haven't actually buttoned it back up yet.

HELP????

We'll have to discuss more with Fred. I would have thought the common error would be to call a gap too small, as it should be harder to put a "too big" feeler in. That's why I would re-spin the engine over and remeasure... in case the gap grew... other things come into play too if you don't stop in the same position or things seat differently on the second spin.. I don't worry about a thou. but I like to look for repeatability in the reading I got. Spin a third time if need be (notice how my way will take longer!!). I would re-shim to the loose side also, as the gaps should be tighter with wear.

Thoughts Fred or did I misinterpret?

Yes, that (bolded sentence) is what I was saying too. If an error in measurement was being made it would be that the gap was being called as being smaller than it actually is because the checker wasn't able to get the feeler in.

Just jamming a feeler gauges into the gap is a go/no-go situation of sorts. If you can't get the .006" feeler in on the intake, or the .007" in the exhaust, then the gap is tighter than spec. If you can get it in there, it is OK. You'd be hard pressed to force open a valve against its spring just pushing on the end of a .007" thick feeler.

And Matt, I agree with your thinking. If I was going to remove the cam for re-shimming I would shoot for the wider end of spec as that will give you the longest time before the next adjustment is needed. The range of the spec is tight enough that the engine will run perfectly fine anywhere in that range.

 

[mattster31]

Crap, you guys are making me doubt myself here!! I just went through a shim check and all but 3 were over (on the tight side) the 3 in question were right on the upper limit. I always thought you re-shim to the "loose side" as valves will wear in the seat and thus will result in a tighter limit as the valve lifts in the shaft. Am I wrong here?? or have I just ordered all the wrong shims?? Good thing I haven't actually buttoned it back up yet.

HELP????

We'll have to discuss more with Fred. I would have thought the common error would be to call a gap too small, as it should be harder to put a "too big" feeler in. That's why I would re-spin the engine over and remeasure... in case the gap grew... other things come into play too if you don't stop in the same position or things seat differently on the second spin.. I don't worry about a thou. but I like to look for repeatability in the reading I got. Spin a third time if need be (notice how my way will take longer!!). I would re-shim to the loose side also, as the gaps should be tighter with wear.

Thoughts Fred or did I misinterpret?

Yes, that (bolded sentence) is what I was saying too. If an error in measurement was being made it would be that the gap was being called as being smaller than it actually is because the checker wasn't able to get the feeler in.

Just jamming a feeler gauges into the gap is a go/no-go situation of sorts. If you can't get the .006" feeler in on the intake, or the .007" in the exhaust, then the gap is tighter than spec. If you can get it in there, it is OK. You'd be hard pressed to force open a valve against its spring just pushing on the end of a .007" thick feeler.

And Matt, I agree with your thinking. If I was going to remove the cam for re-shimming I would shoot for the wider end of spec as that will give you the longest time before the next adjustment is needed. The range of the spec is tight enough that the engine will run perfectly fine anywhere in that range.

Thanks for the advice guys! That was my thought anyways, and I did spin the motor probably 5-6 times to verify my measurements......on two separate occasions. Now I'm just waiting for my order to show up so I can start re-assembling......now I just need to start looking for a used GENII rear shock (should've pulled the trigger on one of the few I saw in the past few months.....) :huh: I will spin them and re-check the new shim clearance before I hook up the chain.

 

[RadioHowie]

I will spin them and re-check the new shim clearance before I hook up the chain.

Just make sure no piston is at TDC when you manually spin that cam! It's bad enough if the motor creates its own "Interference Test".

You don't want to be the one responsible for a bent valve or two (or six)!

 

[yamafitter]

We did three valves checks during the Bustanut Tech Weekend just past. This was the first valve check for both UselessPickles (27000 miles) and my bike (30000 miles) and neither bike needed any shims changed.

BikerGeek's bike had 72000 miles but Andy had never done the valve checks since he has owned the bike (an '03 bought used). Andy's bike was out of spec on a number of valves and had shims changed out to bring everything back in line.

I made an Excel spreadsheet for logging clearances and shim thickness. If you need new shims once you enter the measured clearance and 'as found' shim thickness, the spreadsheet will calculate the required shim to bring you to the ideal (mid-point) clearance. You can then enter the 'installed shim' thickness and the spreadsheet will calculate the new theoretical (expected) clearance. It looks like this...

If you would like a copy of the spreadsheet PM me your e-mail address and I will send it to you since I cannot send the spreadsheet as an attachment over the forum.

 

[mighty mouse]

5000km from my first check - glad to hear they don't need much adjustment.

 

[BikerGeek99]

BikerGeek's bike had 72000 miles but Andy had never done the valve checks since he has owned the bike (an '03 bought used). Andy's bike was out of spec on a number of valves and had shims changed out to bring everything back in line.

Yep - something like 6 had to be changed.

Couple of small things:

* The bike's an '04 that I bought 3 years ago.

* 76K miles on the clock. When I bought it, it had 44K miles so it had been at least 32K miles since the last check.

I envy those who have higher-mileage bikes and don't have to change any shims.