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Old 01-03-2010, 03:27 PM   #1
codyrides OP
The Milkman
 
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Joined: Sep 2009
Location: Santa Fe, TN
Oddometer: 107
Wee valve shim lapping by hand How To

So I was asking around about doing the valve adjustment on my K8 wee in this thread.

I ended up getting some excellent responses and suggestions. Particularly from duckrider, who suggested that I lap my own shims. So much more accuracy than using the factory .5 MM increment replacements, or even the illustrious .25 MM shims that were hinted to exist. Duckrider’s solution was simple. Use 400 grit wet/dry sandpaper on a flat surface, lubricate with WD 40 and grind slowly away.

Well I thought about it and it dawned on me. I don’t need the sand paper, I have another tool for the job. A few years back I studied Japanese food at a Sushi Bar. Two nights a week after my day job. One night in the kitchen, and one night behind the bar. One of my biggest tasks was to learn not just how to use the variety of blades at my disposal, but how to keep them razor sharp. And how to do it without ruining the shape, the bevel and the balance of the blade. That is when I was introduced to Japanese water stones. They are very much like whet stones I had seen before but are lubricated with water rather than oil. For this job, I decided to use my 800 grit cutting stone and my 6000 grit polisher.



First I tried a back and forth motion on the cutter, but found that that lapped it unevenly.



I settled in on a circular motion.



I made sure to lap the side that was factory marked to avoid them being mis identified in the future.



I measured after every 30 seconds or so of lapping.



Since my Mic is in inches, I converted all my measurements to SAE and went from there. Here, my target shim thickness was .067 inch. It started at .0705. Getting there.



Right as I approached the mark, I switched to my polisher to give the shim a mirror finish. Sorry, no pics of that, my little digicam just couldn’t capture it.

After the polish grind, I washed the shim in alcohol, then WD40, then oil before re-installing it.

So as of right now, I have done the entire rear cylinder, and re-installed everything except the valve cover. Here are my old and new measurements (converted back to MM).

I1 - .089 -> .178
I2 - .102 -> .178
E1 - .203 -> .279
E2 - .203 -> .279

I should get the front done next weekend, and have this task behind me.

Big thanks to everyone that had helpful suggestions. They made it really easy to do.
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08 wee - mine
05 DR200SE - wife's

codyrides screwed with this post 01-03-2010 at 09:15 PM
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