Perhaps I spoke too soon. You guys are ruthless.

Quote from: Electrojake on October 27, 2014, 05:12:15 PM
Perhaps I spoke too soon. You guys are ruthless.

Yea the circle of regret is growing.
but that "EEEEEEBBBBBBBOOOOOOLLLLLLAAAAAAA" is just phenomenal.
Cool.
Buddha.

Buddha,
I want to ask a "why do my valves get tight" question.
Where do you suggest I post it? 
No, really.

Quote from: Electrojake on October 27, 2014, 07:15:09 PM
Buddha,
I want to ask a "why do my valves get tight" question.
Where do you suggest I post it? 
No, really.

lmfao

Quote from: Electrojake on October 27, 2014, 07:15:09 PM
Buddha,
I want to ask a "why do my valves get tight" question.
Where do you suggest I post it? 
No, really.

Hell, my next question was why do tires slowly lose air. 
No really. Cut me a break here.

Darnit EJ, you are makin' me chuckle awkwardly at my phone...  people are staring 

- Bboy

Quote from: BockinBboy on October 28, 2014, 02:10:39 PM
Darnit EJ, you are makin' me chuckle awkwardly at my phone...  people are staring 

- Bboy

He he, he's becoming quite the master of the "deadpan" on this thread isn't he.
Cool.
Buddha.

OK, the valve question was to settle an argument (um discussion?) between my son and I.
And we were speaking primarily the "exhaust" valves since they are more frequently tied to catastrophic engine failures.

Historically it has been stated that the wearing in of the valve-seats cause the valves to inch ever closer to the cam.
Left unchecked this seating-in may eventually create a valve stem that has backed right up against the shim/bucket/cam. (i.e. Zero clearance, or worse, negative clearance). Then the seats start to burn/erode and bad things follow.

Back to the argument...
My son's version of the story is that valve seat wear only explains the very small part of the problem. It's actually the valve itself stretching from the constant tap & pull of the spring while the valve is under extreme heat load.

Then he produced a few pictures of industrial engine exhaust valves that had been stretched. Some were so bad that you could actually see a dimple starting to form in the face of the valve as the stem was being pulled backwards out of the valve itself.

Sorry for the long post but jeez, you guys are a tough crowd.

Quote from: The Buddha on October 28, 2014, 02:15:12 PM

Quote from: BockinBboy on October 28, 2014, 02:10:39 PM
Darnit EJ, you are makin' me chuckle awkwardly at my phone...  people are staring 

- Bboy

He he, he's becoming quite the master of the "deadpan" on this thread isn't he.
Cool.
Buddha.

buddha, hes taking over your job lol

Quote from: Electrojake on October 28, 2014, 03:38:50 PM
OK, the valve question was to settle an argument (um discussion?) between my son and I.
And we were speaking primarily the "exhaust" valves since they are more frequently tied to catastrophic engine failures.

Historically it has been stated that the wearing in of the valve-seats cause the valves to inch ever closer to the cam.
Left unchecked this seating-in may eventually create a valve stem that has backed right up against the shim/bucket/cam. (i.e. Zero clearance, or worse, negative clearance). Then the seats start to burn/erode and bad things follow.

Back to the argument...
My son's version of the story is that valve seat wear only explains the very small part of the problem. It's actually the valve itself stretching from the constant tap & pull of the spring while the valve is under extreme heat load.

Then he produced a few pictures of industrial engine exhaust valves that had been stretched. Some were so bad that you could actually see a dimple starting to form in the face of the valve as the stem was being pulled backwards out of the valve itself.

Sorry for the long post but jeez, you guys are a tough crowd.

sorrry my friend, many people here have a slightly dirty mind, myself included lol. Trying to improve that for the better, but my friend i couldnt resist lol

Quote from: Electrojake on October 28, 2014, 03:38:50 PM
OK, the valve question was to settle an argument (um discussion?) between my son and I.
And we were speaking primarily the "exhaust" valves since they are more frequently tied to catastrophic engine failures.

Historically it has been stated that the wearing in of the valve-seats cause the valves to inch ever closer to the cam.
Left unchecked this seating-in may eventually create a valve stem that has backed right up against the shim/bucket/cam. (i.e. Zero clearance, or worse, negative clearance). Then the seats start to burn/erode and bad things follow.

Back to the argument...
My son's version of the story is that valve seat wear only explains the very small part of the problem. It's actually the valve itself stretching from the constant tap & pull of the spring while the valve is under extreme heat load.

Then he produced a few pictures of industrial engine exhaust valves that had been stretched. Some were so bad that you could actually see a dimple starting to form in the face of the valve as the stem was being pulled backwards out of the valve itself.

Sorry for the long post but jeez, you guys are a tough crowd.

Valve clearances are a few 1000's of an inch. I doubt any strecthing can take place in that gap.
If it does, valve clearance will be 0 very quick and it stops stretching.
Cool.
Buddha.

Quote from: The Buddha on October 28, 2014, 06:03:28 PM
Valve clearances are a few 1000's of an inch. I doubt any strecthing can take place in that gap.
If it does, valve clearance will be 0 very quick and it stops stretching.
Cool.
Buddha.

Lets say the valve check interval is every 7000 miles.
Granted the first valve lash check on a new bike is the most important.
But even after that one would expect to always be installing slightly shorter shims throughout the life of the engine. Yes?
And in your "opinion" the reason for this is the wearing of the valve seat. Yes?

Pssst... If you agree with me, I win the bet. 

Well, if stretching were true... then when a valve that was broken due to zero/negative clearance were replaced - wouldn't a newly replaced valve go back to larger shims? (I don't recall that being the case for gsJack's bike)...  or is my thinking totally elementary and I should just shut up?

- Bboy

It has been my experience GS exhaust valves set at Suzuki's min .001" (.03mm) clearance will require constant changes to smaller shims as the valves that are running too hot without ample seat cooling time recede into the seats.  The tighter one on my 97 was down to a min 215 shim at 80k miles.  When my 02 started to follow the same pattern I went to my wider .003-.005" setting and exhaust shim changes were not required much after that almost as good as intakes which required none.

I replaced a broken exhaust valve caused by a too tight bucket at about 20k miles and put in a like new valve (6k miles) using the same shim and got about the same clearance it had before, .002-.001".   

http://img.photobucket.com/albums/v443/jcp8832/GSvalvelogs_zps55f27f5e.jpg

Valves and seats both wear but I've never seen/heard of them stretching in either bike or car applications.  We did a lot of valve work on cars 60-65 years ago that's not required much now.

Thank you for the info.
You fellows have "experience" while I have simply have curiosity on the actual cause and effect.

I'm sure that lots of hobby-grade motorcycle owners such as me have been checking and setting their valve clearances without ever really understanding the what & why of the whole thing.

Thanks again, 
-Ej-

My 48K miler always needed thicker and thicker shims.
The rest of em - no idea, I never held on to any past 1-2 to have a pattern.
I also had a crows foot shaped scratch on one cam, that scratch got fainter and fainter for the 40K miles I had it. Seemed to make no difference to anything.

I dont believe the recessing into the head is all the wear that occours. I believe shims wear, buckets, tops of the valve as well as the cams themselves wear too. I've measured shims almost measure 1 whole size under. Of course who knows what the shims were in their previous life. Someone may have hit em with a belt sander. I wrote the numbers down as I measured them, and when pulling them out I measured them again. I barely got them to wear. But I needed thicker and thicker.

Maybe my shims got ebola Hey we're back on topic.

Cool.
Buddha.

So far, more Americans have been married to Kim Kardashian than have died from ebola.

And the ebola victims suffered less