Valve clearance

[BassCliff]

Another thought

Hi Mr. JATO,

The first time I adjusted my valves I had to go down 2 sizes on a couple of shims. I don't think the valves had ever been adjusted (13,800 miles when I bought the bike). After you insert a smaller shim, are you spinning the motor a few times to "seat" the new shim in the bucket, then re-measure?


Thank you for your indulgence,

BassCliff

[psyguy]

if you re going two sizes down on shims and still not getting enough clearance id assume you re doing something wrong
id start over
use mm feeler gauges to avoid confusion
you need to have an extra shim when swapping them around so no bucket is left without a shim while you re turning the camshafts

measuring the distance between the bucket and the shaft is not going to work as its practically impossible to get an accurate measurement of that space

as there are some discrepancies in the methods used, make sure that the 2 adjacent lobes are away from the shim at the same time (ie, neither of the two is pressing on the valve)

[JATO]

I'm spinning the crank, on the cylinders I could do so I went down 4 sizes, and I did start over and put everything back the way it was. I'm going to let it go for now since it was running like a rare hair last fall and come back to it when I regain some patience.

[bwringer]

Well, ignoring the problem certainly won't make it go away... I'd reallllllllllly recommend that you either figure out what the problem is with your procedure or get the clearances set correctly pronto.


I have a 2.15mm shim, the thinnest available, I use in baffling zero-clearance situations like this. If it's still zero with that shim in place, the valve is burned. With the 2.15mm shim in place, you can measure the (hopefully) large gap and go from there.

I have needed to go down four or five shim sizes in a few cases of neglected bikes, so yes, it can definitely happen.

The only other thing I can think of is that two or more of your feeler gauges are sticking together. This seems to happen to me at least once every time I check valves, and I'm sure it's something you've encountered before as well. A .0015" feeler is pretty much just a floppy slice of foil you can dang near see through. Just a thought.

[psyguy]

if you think its running really well and 4 sizes down on shims is not enough, well somethings definitely wrong as these two things are incompatible
for the bike to run properly valves have to be in spec
you can notice a difference in how the engine runs when only a few shims that are out of spec by just 1 size are brought back to spec...

neglect in this department can lead to expensive damage

[JATO]

I'm doing other work to the bike right now and it is no where near running at the moment, so the valves can wait. Thanks bwringer for the idea of finding a baseline with a 2.15 shim. I'm not surprised I didn't think about that, I currently have three of my own vehicles in my shop right now that I'm working on and my brain and patience are stretched thin between them.

[bwringer]

CRC2 stocks Suzuki shims down to 2.30mm for $4.95 each, or you can order Gin-yoo-wine Suzuki shims from your favorite Suzuki parts source down to 2.15mm for about twice as much. Part number 12892-45000-215.


Scrounge around at your local fleabag independent cycle shoppe -- very few Suzuki dealers keep shims around any more, but the old-timers usually do.

Purely for static testing purposes, you could also temporarily fit a 29mm diameter shim (as used on Kawasaki/BMW/Yamaha) bikes if that's easier to get. As long as you don't run the engine with it in place, it could be helpful.

The Suzuki shims are 29.5mm diameter, so you'll definitely want the correct shim in place before you try to start it, or all sorts of expensive hell could break loose.

[JATO]

I ordered a 2.15 shim from MR Cycles and once it gets here I'll start from square one.

[IOWA450T]

Possible easy fix

Probably not going to be the case but I had the same situation where I couldn't get my smallest feeler guage between any of my shims and cams. Using Steve's super easy spreadsheet I was sure I could move shims around and only ordered two new ones. Imagine my surprise when I still couldn't get the feeler guage in after changing the first shim....or the second....or (well, you see where this is going). That's when I discovered that two of the blades of my feeler guage were stuck together and I was really trying to fit a .089mm blade in, not an .038 like I thought (.038+.051=.089). I wound up using the new shims and moving someothers around but still came up one short. Had to wait another 3 days to get one but then was able to finish up.
I felt kind of stupid so I didn't post anything about it but when I read your post I had to throw it out there.

[Nessism]

I wouldn't go all the way down to 2.15 for a checking shim, too far away from where you are going to wind up. A 2.4 you will get more consistent readings.

BTW, most likely you have a burned valve, or at least one that's getting pretty crunchy. That's what happens when maintainance is neglected; the valve is left slightly open which in turn leads to rapid deterioration. You would most likely only have to go down one or two sizes, instead of four, if the valves were properly taken care of. Something to keep in mind for those that put off things like checking the valves.

[80GS750]

i gotta say... i didnt get the whole shim checking thing at all until i read basscliffs write up ... now i feel confident in checking my own and doing it myself!!!!!

[JATO]

I have good compression and leak-down test is good also. I took a look into my ports and they're good too. I doubt I have a burnt valve.

[greg78gs750]

so, a question for the experts: how do you know if you have a burnt valve? compression test?

[Nessism]

I have good compression and leak-down test is good also. I took a look into my ports and they're good too. I doubt I have a burnt valve.

Hopefully you don't. Seems strange that the valve would still be sealing properly with the clearance more than four steps out of adjustment.

[doctorgonzo]

Only slightly off topic, I can't find the valve shim trade thread... I know there is one. I have some 2.65, 2.60X and 2.60 I'd like to trade for 2.55 and 2.50