Shim Pool

The general Seca II forum. XJ600 centric but all motorbikes welcome!
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Drapheus
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Mon Nov 14, 2011 3:05 pm

You should be checking your valve clearances -- at least every 5k miles. Making sure your valves are opening the correct amount is critical to the longevity of performance and engine life!

You can buy shims OEM ($8-$15 ea. depending on where you go) and find some shim kits on eBay, but this thread is for anyone who has extra shims lying around and is willing to swap or donate to someone in need. Post what shims you are willing to part with or which ones you need.

I have a 285 and 275 (maybe a 265, too).

(I've got a valve adjustment how-to in the works for those who need it)
'92 XJ600 - 50k | '95 XJ600 - 5k
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swartz77
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Mon Nov 14, 2011 3:11 pm

Excellent idea!

Heck, I think as a community we could have swap/pool post for general parts, or OEM specifics. (okay, I'm done, don't want to muddle up the nice shim pool post) :)

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radare
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Mon Nov 14, 2011 3:55 pm

This is a great idea! Im shimless though; I've been thinning mine with sandpaper.

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azman857
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Mon Nov 14, 2011 4:08 pm

The hardness is only a few thousands deep. So sanding is not a good idea. After you get through the hardness your at regular metal and it will wear faster and maybe gouge the cam. My .02 worth
I don't have a plan and I'm sticken to it! 1980 XS 650 SG, 1992 XJ 600 Seca II, '78 KZ 650 Custom.
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1Oldman
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Mon Nov 14, 2011 4:12 pm

I have about 20 or so extra shims, a lot of which are duplicates. Bought them from a guy on ebay getting rid of his CBX parts. I suppose I could take an inventory to see what I actually have. Which leads up to another point, several other bikes and even a few cars use these same shims so it wouldn't hurt to sort that out when you go looking for shims. I believe the car shims I ran across were a lot cheaper than the bike shims.
Better to be over the hill than under it.

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Drapheus
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Mon Nov 14, 2011 5:32 pm

azman857 wrote:The hardness is only a few thousands deep. So sanding is not a good idea. After you get through the hardness your at regular metal and it will wear faster and maybe gouge the cam. My .02 worth
+1

That's some good info as well, 10ldman. I know I've used some CB750/900 shims -- as long as they are 25mm in diameter they should work.

I really really wish Yamaha stayed with the 29mm shims like in the 80's XJs!
'92 XJ600 - 50k | '95 XJ600 - 5k
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radare
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Mon Nov 14, 2011 6:24 pm

azman857 wrote:The hardness is only a few thousands deep. So sanding is not a good idea. After you get through the hardness your at regular metal and it will wear faster and maybe gouge the cam. My .02 worth
Shims are typically case hardened via carburizing. The manufacturer heats them up and holds them at a temperature of say, 1750F. After a set amount of time (routinely 4 to 10 hours), the grain structure of the steel changes and then the grain structure is frozen by quenching the shim in water, oil or air (depending on the properties one wishes to attain). This produces a hardness layer that is commonly in excess of 0.050" thick. The amount removed by sanding the shims is on the order of 0.001" which doesn't cut away the entirety of the hardened layer.

I typically sand the bottom portion of the shim; the portion that contacts the bucket. This is because the shim/cam wear together and it's common to keep these wear surfaces together.

But to be fair, I only do this if I'm within a thousandth or so of spec and I do it in a pinch, to get by until shims arrive from BikeBandit. If you have to chose and a new shim is available, yes, by all means, use the new shim!

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1995secarider
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Thu Nov 17, 2011 3:59 am

i have 5 2.75 shims. brand new un opened package.

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radare
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Mon Nov 21, 2011 3:20 pm

Might mention in this thread that the Seca II uses 25mm diameter valve shims. You can find a cross-reference for other bikes with the same shim size here: http://www.sudco.com/25valveshims.html

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siniraag
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Fri Dec 02, 2011 2:46 am

Hi guy's.
I would like to change my shims from
265 to 260
276 to 275
270 to 260
262 to 250

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