[capo998]

Checking the valves on my 2012 with 135k miles. Previous checks were at 104k, 69k, 52k and 30k. Shims were required at 30k only.

The intakes haven't budged since 30k. Both exhaust gaps have increased slightly since the last check. The right exhaust went from .008 to .010. Still within spec. The left exhaust went from .011 to .012. The left exhaust was at .009 after the shim change at 30k. It has been at .011 at all other checks except for this recent one.

I have two questions to put out to the brain trust.

Generally gaps decrease. What would cause valve gaps to increase? It's OK to say piss poor measurements!
And at previous checks I called the .011 ok as it was only slightly out of spec. (gaps decrease right!?) Would you leave the .012 or is that too much out of spec? Of course it's the left exhaust which I think is the most fiddlely to change.

Thanks

 

[a4twenty]

wear on the cam or shim face..... or perhaps carbon / junk build up on the valve seat.

has, it run low on oil?

take it apart and look for damage, if it all looks good I'd probably adjust those ones to the middle of the spec and forget about it. after those miles I doubt your valves are going to get any tighter.

 

[ymracing]

Time for an Eyetalian tune-up...;-)

 

[capo998]

Never run low on oil. I've had the bike since 4,000 miles. The cam lobes look pristine.
I did a EM 685 at 52k and didn't send my head for Mike to clean and rebuild (as he recommended) so carbon build up sounds like a possibility.

OK, I'll bite. What's an Eyetalian tune up?

 

[tomo]

135K ! Sir, I tip my foil hat to you. How come you don't post more travel stories ?

 

[SirMarksAllot]

Never run low on oil. I've had the bike since 4,000 miles. The cam lobes look pristine.
I did a EM 685 at 52k and didn't send my head for Mike to clean and rebuild (as he recommended) so carbon build up sounds like a possibility.

OK, I'll bite. What's an Eyetalian tune up?

I think it’s just run the snot out of it, or blow the soot out😉

 

[PeteK]

It's odd that gaps open. Report back what you find when you take off the cam caps.

 

[KLR Kool-Aid!]

135K ! Sir, I tip my foil hat to you. How come you don't post more travel stories ?

Agreed - I'm shooting to hit 100k miles this summer, and this is inspiration! There's a special place for KLRs with miles like that.

 

[KLR-Mule]

135K ! Sir, I tip my foil hat to you. How come you don't post more travel stories ?

Because he’s too busy RIDING!
He doesn’t have time to shoot the breeze on this here forum 😆

My hat’s off to you. Love seeing KLR owners who actually USE their bikes!

 

[capo998]

So, now I'm thinking that I have a worn shim somehow. Not sure if that's even possible.

I was going to run with a4twenty's advice and re shim it to the middle of the spec range. Jumped on the handy dandy shim calculator and it gives me a requirement for a 255 to get to a clearance of .008in. There was a 245 in it to start. I look through the shims that I have and I have a 255. Great.

Then the head scratching starts. I have this 255 because it came out of the bike at the first and only time I changed shims at 30k. And of course it came out of the same left exhaust I'm working on !! I went ahead and installed the 255. Torque, torque, install tensioner. Nothing down the abyss. Rotate the engine a few times. Check the clearance. .005in. Faak.

I looked back at my records from when I did the re shim at 30k. Wanna guess what the clearance was that caused me to change the 255 at that time? Yup .005 ! What brain power I have left at my age can only point to a worn 245 shim somehow.

I'm going to order a new 245 and a 250. That'll be what the shim calculator suggest depending on the desired clearance I input.

By the way, the cams and the cam caps look perfect.

 

[pdwestman]

Where is your micrometer or caliper?
2.55mm x .03937 = .1003954inch, so just call it .100 inch thick.
A 2.50mm would be .002 inch Less at .098 inch.
A 2.45mm would be another .002 inch less at .096 inch.

But I've seen them vary +/- .0005inch.

And I've seen Mis-Marked shims & not-marked shims & numbers worn-off shims.

Is it a SNUG .012"? We need to take up the cam bearing clearance with our feelers, just like a rotating cam lobe will.
With .012" clearance on that ex valve I'd be shooting for a snug fitting .010" or a sloppy fitting .008" or smile at .009".

 

[capo998]

I just measured with a caliper the supposed 245 shim that just came out of the bike and it was right on .096in. I use supposed because as you commented the shim has no numbers that I can find ! Not sure what happened there. My records from 30k miles on Feb. 2016 show that it was a 245 and I am confident that it was, at least at that time. Funny you say that .009 would be a smile. When I installed that 245 in 2016 my final finished clearance was .009in !! I've checked the clearances 4 times since and that valve has increase through .010, 011 and now what might be a loose fitting .012in.

I have a couple of new shims on the way so I'm on hold till then.

My hats off to anyone that can still follow this.

Where is your micrometer or caliper?
2.55mm x .03937 = .1003954inch, so just call it .100 inch thick.
A 2.50mm would be .002 inch Less at .098 inch.
A 2.45mm would be another .002 inch less at .096 inch.

But I've seen them vary +/- .0005inch.

And I've seen Mis-Marked shims & not-marked shims & numbers worn-off shims.

Is it a SNUG .012"? We need to take up the cam bearing clearance with our feelers, just like a rotating cam lobe will.
With .012" clearance on that ex valve I'd be shooting for a snug fitting .010" or a sloppy fitting .008" or smile at .009".

 

[terry_g]

The shim will not wear at the outside edge so a caliper will read the thickness of the shim at the edge.
Do you have a micrometer? measure the thickness of the shim near the centre and a t the edge.
That will tell you if its worn.

 

[capo998]

Only calipers. No mikes. Looking at the shim in question it is very shiny on the very outside edge of the face that is away from the cam lobe. And quite a bit more shiny than other used shims I have on the face that contacts the cam lobes. Although the other two only have 30k miles while the this one has at least 105 and maybe 135.

Where and how much of the shim contacts opposite (bucket side?) of the cam lobes?

I'll be ordering up some micrometers while I waiting for the new shims.

 

[capo998]

Update: I recieved my new shims and a quality $40. micrometer! I measured the 245 shim that was in the bike at the start of this project. It measured out at 2.435/2.436. Including the new shims I just recieved, all the other shims I have (5) measure at least right on or slightly larger.

It sure looks like I had shim wear which would explain why I had increasing clearances on this exhaust valve. It also explains why I had a tight clearance after replacing the shim with the shim calculator recommended size.

After "tricking" the shim calculator it recommended a 250 which I installed and I now have a .009in clearance. Happy.