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Old 09-21-2010, 06:37 AM   #52
HighFive OP
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Joined: Nov 2006
Location: Okiehoma
Oddometer: 2,631
So, everyone is dying "to know"...... what was my valve clearance? Let's check and see!

First thing, you need to get yourself one of these nifty, old-fashioned, gadgets:



This is a plain 'ol Feeler Gauge which you can buy at most any Auto Parts store. Just make sure you get one that has both metric & english measurements indicated on the individual gauges (as you can see in this photo). It makes the job a lot easier if you have more than one bike. Some manuals spec clearance in "inches", while others list "mm" (millimeters). That way, you don't have to keep converting your measurements. You'll be confused enough trying to remember "more is less"...."bigger means smaller" if & when you are figuring out how to interpret your valve clearance adjustment.

One the left sidecase, remove these two plugs to expose the "timing marks":



At first, I was alarmed to discover oil in here:



Thought I had a main seal leak in on my crank centercase. Didn't think the electrical power generation station (magneto / alternator .... gets called all kinds of names) should be spinning in a bath of oil. I'm so used to working on 2-strokes, all my life. But the Krabill assured me, all was well. Same thing on my mighty KLR (which I've just not noticed before). And now, I see the O-ring seals in the caps....in this photo. So, I can sleep ok.

Remove the Spark Plug to relieve compression from the Head. Then, using a sprocket wrench on the mag nut (in the big hole) slowly turn the crank counterclockwise until the "single" timing mark aligns with the single mark in the side of the small hole.....like this:



Kind of fuzzy and hard to see, I know. My little camera doesn't take macro shots (close ups) very well. But you get the idea. CAUTION: there is another mark on the mag (in that small hole) that comes around just before the little single timing mark. It looks like an "H". I'm not certain what that one is for (someone else can chime in to explain). But, don't use that one. Align with the single mark that follows it.

Once aligned, look up top at the camshaft sprockets. There are alignment marks stamped into those, as well. In this position, which should be "Top Dead Center" (TDC) of the Compression Stroke, all 4 of these marks should be aligned parallel to the top of the Head.....like this:



Look closely and you can see 3 of them near the edge of the head.....along a horizontal line. The 4th mark is off to the left in the shadows (out of sight). Study these postions and maybe even take photos for yourself, before you remove your camshafts from the engine. You will have to set all these timing marks back to this exact position when you put the engine back together....or it won't run right, if it runs at all. Actually, you could seriously damage something (like your valves) if you fail to do this correctly upon reassembly. I'll cover this in detail upon reassembly.

Now, look at the right side of your motor and the camshaft lobes will look like this:



Notice each lobe is pointed to the outside (away from center....opposite of each other). This is the target we are after. The valve clearance must be measured at TDC, with the camchain still under tension, like this:



We measure the gap between the cam lobe and the lifter beneath. Find the feeler gauge that just slides in between with some resistance. Usually, the next larger size won't fit, and the next smaller size is too easy (no resistance). Read the number on that gauge and right it down on a sheet of paper. Draw a little diagram so you know which valve position has which measurement (Left Intake, Right Intake....Left Exhaust, Right Exhaust). The Intake valves are at the back of the motor on the airbox side, and the Exhaust valves are at the front of the motor on the pipe header side. So, in the photo above, I am measuring my Right Exhaust valve clearance.

Next, compare those measurements to the specified range listed in the Service Manual.....which is this:

Valve Clearance (cold)
Intake 0.13 - 0.20 mm
Exhaust 0.23 - 0.30 mm

And now.....drum roll.............................................. my measurements were (at approximately 8,000 miles):

Left Intake 0.13 mm
Right Intake 0.13 mm

Left Exhaust 0.23 mm
Right Exhaust 0.23 mm

I could force a 0.15 mm into only one of my Intake gaps, but decided it was much too tight to be correct. So, I accepted that both were 0.13 mm in clearance.

So, every one of my valves were sitting right on the lower limit. That means they were on the edge of being too tight. Valves get tighter as the parts were down. When you adjust valve clearance, your goal is typically to increase the gap to somewhere near the larger end of clearance.....so, they can slowly wear down toward the lower limit again.

The question of the day: Where did the factory set my valves upon initial installation? They don't say. If they were set dead on this lower limit, then my valves haven't moved a tiny bit. If they were set in the middle of the range, then they have worn some (which would be my normal expectation). If they were set at the upper end of the range (which is where the manual tells you to reset them to), then they have worn a lot in just 8,000 miles. I can tell you the factory used shim pads with .01 mm increments to get it perfectly where they wanted it. For some reason, we are only allowed to work in .05 mm increments, because that's all the motorcycle shops ever seem to have on hand.

The Answer: Who knows! I ain't got a clue.

What I do know, is I do not want my valves running "too tight". Nope, nada, no way. Mine were currently "in spec", so all was fine. But would it stay that way? For how long?

So, I'm going to adjust mine right here and now.....because this is definitely something that would keep me awake at night....pondering....and you know how I feel about that. I'd have to start popping sleeping pills to get a good night of sleep.

Next up, we'll pull the shim pads and have a close look at them.....then go hunt down some new sizes. Refill your popcorn!

HF
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HighFive screwed with this post 09-21-2010 at 06:45 AM
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