The purpose of this page is to explain, in detail, how to check and adjust the valves on a KLR650. This is intended for people with modest mechanical skills, and/or those who have never undertaken a job such as this; I made an effort to be very specific about each step.

This is not a quick-start guide by any means, but rather is intended for people who are interested in doing their own work, and who prefer to work with a guide that spells out each step of the process.

NOTE: The picture above shows the top of the engine with the valve cover off. You've got to work for it, but about in the center of the red circle is a slot in the "cup" that hold the shim. You can easily turn this "cup" until the slot is easily accessible - this is where you'll use a fine screwdriver, or tweezers to lift the shim out once the lobe has been lifted.

You can also break the oil suction, and get the shim out more easily if you direct a short blast of air from an air nozzle at the cutout in the bucket. Be ready to prevent the shim from becoming a frisbee in case too much air is applied.

Second. The intake is the back / carb side of the engine. The exhaust is the front / headlight side of the engine. Looking down at the top of the engine you'll see the 4 cams with shims underneath each one. They are:

Front Left = Left Exhaust <> Front Right = Right Exhaust <> Back Left = Left Intake <> Back Right = Right Intake

The picture above shows the Top Dead Center mark, TDC. On the lower left side of the engine, in the area just forward of the gear shift, are 2 round plastic slotted covers - a large one in the middle and a smaller one above it at the top. Both of these need to removed.  A deep-well socket, or one with an extension, is used to turn the "nut" in the center hole counter-clockwise. Warning! Do not try to turn clockwise. If you miss the timing mark, even by a hair, go around again.

You'll be watching for two things here; stroke and TDC mark. While turning the socket counter-clockwise, watch the intake cams and their valves. The cam will come around (counter-clockwise), and the more narrow tip of the cam will push the valve open, and then release the valve and allow it to close. You're getting close.

As you slowly continue to turn, the cam tip will begin to release the valve and allow it to open. Now, look into the smaller upper hole that you removed the plastic cap from. You're looking for the 3rd of three marks, and they aren't far apart. First you see I, and then F, and finally the one you want, T. The leg of the T should be perfectly lined up with the notch cut in the bottom of the hole. Top Dead Center!!

Note: At this point the marks on the camshaft sprockets point forward, and line up with the surface of the cylinder head.

Intake: 0.10mm – 0.20mm (0.004in – 0.008in)      <>     Exhaust: 0.15mm – 0.25mm (0.006in – 0.010in)

The Cam Chain tensioner bolt is shown above. Ok, the abyss is no longer an abyss, you're at TDC, have all 4 clearances correctly recorded, and are ready to proceed.  On the upper left back side of the engine you'll find the cam chain tensioner - a larger center bolt head, (12mm), in a neck secured at the base to the engine by two smaller bolts, (10mm.) Remove only the 12mm center bolt, which is holding in a long, compressed spring. Be careful, as you remove the bolt, that the spring doesn't go shooting out and get lost.

The reason the spring is removed from the tensioner before the cam(s) are disturbed is so it cannot get tighter either during the procedure. Nothing you are doing during the valve adjustment would cause a need for the tensioner to be tighter or looser than when you started unless the cams were disturbed before the tensioner was disabled by removing the spring.

All this is written assuming a full, 4 valve clearance check. Note that the shims you removed were placed with the size numbers facing down, this is so the cam doesn't wear them off. Be sure to re-install the new shims number side down.

If the size numbers ARE worn off, all is not lost. Obviously, if you have a micrometer or digital calipers that would be the easiest way to check the shim size. If you don't have either of these measuring devices:

- place the shim on a perfectly flat surface such as glass.

- lay a shim of known size tightly next to it, edge-to-edge. (from your spares or another bucket)

- slide a finger nail across the surfaces from one shim to the other. Do this in both directions. A size difference will show up when the fingernail catches on a shim edge. If it doesn't, then you're probably good to go.

- You'll want to scribe the center of an unmarked shim to avoid this trouble the next time. Do it now based on the assumption that you've gotten the size right, or install the shim and measure the clearance.

NOTE: A worn shim can be reused by flipping it over, and scribing the size in the center of that surface. Scribing is done in the center of the shim to avoid having a burr from the scribing cause the shim to sit higher in the bucket. The center of the shim typically doesn't contact the bucket.

You can do the math yourself, or save a lot of hassle and get a great program called ShimCalc from Pat at IronJungle. The website is at: http://www.ironjungle.com/  (ShimCalc Screen Shot)

You will need three bits of information no matter how the figuring is done - Initial Measured Clearance / Stock Shim Used / Desired Clearance. Using ShimCalc, you just plug in these numbers for each valve and the software does the rest. (Stock Shim Used means the shim that was in there when you used the feeler gauge a few steps back to get the clearances.)

I bought the 16 shim set from Fred Hink at www.arrowheadmotorsports.com to get started, and just replace the ones I've used so that I never have to fool around when I need a shim.

I use this shim storage box to keep my spare shims rust-free, and oiled for use.

According to what ShimCalc, or your math has indicated, put in the new shims - shown in the picture above. With the cam caps removed, you can lift the right end of the shaft to make room for the shim to come out. Make sure the shims are clean of protective coatings, dirt, or whatever. I like a light coat of fresh oil, (which comes from removing them from the muffin tin), to get them "started." Make sure the shims are completely seated in the cup when you install the new ones.

You can also break the oil suction, and get the shim out more easily if you direct a short blast of air from an air nozzle at the cutout in the bucket. Be ready to prevent the shim from becoming a frisbee in case too much air is applied.

Clean the top of the engine and the bottom of the valve cover of any silicone that may be on them. Use your fingernail to do this, not a scraper or any other tool - it's important to not damage the machined surfaces.

Alternatively, you can use a plastic scraper of the type that fits into a razor scraper holder. Also, you can form pieces of plexiglass to do the job. If you don't have scrap plexiglass, check with a glass shop to see if they have any in their trash bin. Be sure to clean the plexiglass of any shavings or bits left hanging on.

Use a small amount of non-drying silicone all around the rubber gasket surface of the valve cover. Be sure to wipe off any excess from the inside and outside edges of the cover. Again, you want very little here, just enough to lightly coat the surface and create a seal.

I apply a small line of the silicone all the way around the gasket, then place my index finger on the top of the gasket, my thumb on one side of the gasket and my forefinger on the other side. I then just run around and around the entire gasket / cover surface until I have complete coverage of the gasket using the smallest possible amount of silicone.

Be sure to get the silicone all around the two "circles" on the left side.