Stupid valve question

9 replies to this topic
  • Merfman

Posted March 27, 2002 - 07:35 AM


Hey gang, I'm getting ready to adjust my valves for the first time. Yea, I've checked them on a regular basis and the exhaust valves are a little on the tight side. Anyway, my question is this: Are these adjusted on a bike-by-bike basis at the factory or are there standard shims used?

IOW, I'd like to know what shims I need before tearing it apart, and leaving it torn apart until the shims arrive. The local dealer doesn't carry any shims in stock.

Any suggestions, hints, notes, experiences etc, appreciated...


  • John_Lorenz

Posted March 27, 2002 - 07:41 AM


It is impossible to tell what Shims will be needed prior to tear down. Once the tear down you see what you got, figure what you need and add / subtract what is to adjust. If you local dealer is not stocking this stuff then find what that does ? this is a major part that should be stock on board. Now this is up to you, order a range of Shims + - and keep them handy, if you follow the maint suggested you will probably need to adjust from time to time

Good luck

Oh Ya
Never a stupid question is asked always comes in a stupid answer HA :)

[ March 27, 2002: Message edited by: EgoAhole ]

  • Merfman

Posted March 27, 2002 - 07:46 AM


If I knew what shim was in the thing, I could tell what I needed. I've already measured the clearance, so I know what that is, I just don't know what's in it. I just assumed that all '01, non-Canadian, 426FN's came with the same shims.

And, I'd planned on buying a range of shim, but the damn things are around $5 each. Ouch.

  • sirthumpalot

Posted March 27, 2002 - 08:04 AM


I think they are individually shimmed at the factory. I would expect many to have the same shims, but if I were you I would see what you have before you order. From what I understand you can read the size stamped on the shim when you remove it (haven't had to remove mine yet). Otherwise use a good caliper.

If you order spares for the future I think that it is most likely that the valves will tighten over time so you should probably only pick some up towards the smaller size, IMHO anyway. Good luck!


Posted March 27, 2002 - 08:34 AM


mine were still easy to read(thickness numbers)
i used the old sandpaper and piece of glass and a caliper trick and didnt buy new ones. it worked great, you can adjust to more precise measurements. jimbo

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  • Merfman

Posted March 27, 2002 - 09:35 AM


Thanks for all the replies, guys. I'll just have to pull 'em and see what's there.

  • motoman393

Posted March 27, 2002 - 10:04 PM


I used the same method RIDEPATE did! It works great and allows me to keep my valves closer to the tight end of spec!

  • sirthumpalot

Posted March 27, 2002 - 12:19 PM


What grit paper do you use, and how are you sure that you sand it perfectly square? I like the idea but I'm weary of putting a non-square shim back in.


Posted March 27, 2002 - 12:33 PM


i used some 600 grit wet/dry 3m and did them wet, as long as your sanding on something flat and straight (glass) theres not too much to worry about, it would take a lot of work to sand them un-true, they are made of some very hard steel. i finished them up with a scuff of 1200 grit to polish out the sand marks.

  • motoman393

Posted March 27, 2002 - 01:22 PM


I also used 600 grit wet sandpaper (but I didnt polish them w/1200 they were smooth enough) Just make sure you sand the valve pads in a figure 8 motion this gets the surface as even as possible (I learned this from overclocking CPU's)

The reason I sanded mine down were: Yamaha had to special order the pads (2-3wks) and I wanted to ride on the following weekend. Well it turned out good and doesnt cost anything (if you have a micrometer and 600 grit sandpaper) Next time I adjust my valves/sand the pads down I will take pics and put them on my site (probably in a month or so)! Later,


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