Thanks to everybody for their input and contributions. Thanks to this thread and others, I've successfully checked my valves for the first time. Yes I was slow and nervous but everything went as planned. I was really hoping all 4 valves would be in spec so I could button it back up and ride however I wasn't so lucky. 3 of the 4 are either at the bottom end of the spec or just out of spec on my '09 with 7800 miles. So, I've bought my shim kit, have a micrometer and am prepared to replace the shims tomorrow. One quick noob question before I get going. I'm pretty sure the forward facing valves (closest to the radiators) are the exhaust and the rear valves are the inlet valves. Can somebody confirm this is the case? Thanks in advance.

 

You are correct about valve locations. It's not hard to remember. The exhaust valves are on the side where the exhaust pipe attaches. The intake valves are on the side where the carburetor attaches.

 

thanks. Seems obvious once you point that out. I guess we are all wrenching noobs at some point in time!

 

successfully replaced shims today! I broke my shimming cherry, so to speak. I bought my bike used with only about 2000 miles on it so my guess is that the shims hadn't been checked or replaced until today (7600 miles). I was surprised that of the 3 valves I replaced, each had a different size OEM shim. The exhaust was 3.1 and there was a 3.05 and 3.0 in the inlet valves. That surprised me. I figured all 4 would be the same or at least the 2 exhaust and 2 inlets would be the same.
thanks again for all the input. This place rocks.

 

Excellent pictorials, thanks Relic. I checked mine today. Exhaust and Inlet are all on .20. This means Ex is in spec. but inlet is out. Inlet Max should be .19.
My questions are, as the mileage increases do the valve specs get larger or tighter. Reason that I am asking this is, my bike will not start. Via a process of elimination I checked the valve clearances, hoping to find a smoking gun. Now finding the inlet out, on the loose end by only .01, I am not convinced that this is the problem. Would this cause the bike not to start, even with a hefty fast push down a hill in 1'st gear?

 

I would say that the usual result of mileage would be a reduction in clearance as the valve seat wears it will allow the valve to sink into the head and close up the clearance.

 

If you have a manual cam chain tensioner you can simply back it out about all the way to get the chain loose enough to remove the cams, no need to take it out. Just do the cold adjustment when done doing the valves.

Another tip. After reading about gaskets not fitting properly after having the cam cover off the bike, I figured it could be due to shrinkage. When I did my valves and cam work I did two things to try to preserve the gasket. Here they are with some other tips:

1. Make sure the gasket separates at the cover surface not at the head, that way the half moon part stays seated in the head.
2. Put the cam cover back on the engine if you have to stop working to wait for parts or just don't get it done in one shot. This will keep the gasket shape by keeping it confined where it should be. It can't shrink or deform when pinched in place Just snug the bots up a bit, no need to tighten to max torque. It is just to keep the gasket in place, not allowing shrinkage.
3. So you don't drop the shim, use a small dab of grease on your finger to have the shim stick to it when placing it in the valve pocket. Put it in then slide your finger out, wiping the grease off and leaving the shim in place. I forget if this came from the shop manual or was a tip from another rider.
4. Notice the locator bushings in the head, those holes are where the two long bolts will go.
5. CAUTION, IMPORTANT - When you put the cam cap back on make sure it seats in easily and completely without force. It is a precise snug fit and need be fitted properly. You can tap on it lightly with a screwdriver handle or small plastic mallet, but you do not want to hit it hard or try to draw it down tight. That cap is a machined mate to the head, no easy replacement, if you crack or break it you buy a new head. I make sure the cap is down all the way around before tightening the bolts. I also tighten in three steps using the tightening sequence from the manual - 1) lightly snug to make sure the cap is on properly, 2) torque to half the spec value - in sequence, 3) torque to full value - in sequence.
6. Use a bit of grease on the gasket surface for sealing. Smear a bit of grease in/around the gasket mating surface of the cam cover before reinstalling. The mechanics at the Honda shop where I worked taught us to do that. The grease tends to seal the very tiny gaps that might leak and will not melt away since it is for higher heat. Worked on the hard to seal square corners on the Gold Wing cam covers, which were notorious for leaking and needed valves checked at set up.

I had the cams out few days waiting for shims and also while doing the Marcelino Mod, so I put the cover back on for those times. The results at this point - no leakage. Can't say it's because I did what I did, but it was worth doing to avoid paying for a new gasket and made sense.

One reassuring note on the timing chain - it does not matter if the chain itself moves on the sprockets. There are no markings on the chain, it is a continuous run of identical links, no first link or anything. It's simply a drive chain. The key point is that your piston is at top dead center (TDC) and does not move and that when you put the cams back in that the timing marks will align horizontally with the top of the head (unless you've done the MCM, then the marks are at different positions). That is all that matters - at TDC with the marks lined up when the play is taken out with the tensioner or you rotate the cams back to get all the chain slack to the back, front run tight.

If you should drop the chain down into the cases, just get one of those extendable pen magnets to fish it out. Seen the guys in the shop drop chains in the cases a number of times. Fish it out and go back to task.

You can buy a kit as said, or buy the shims in 5 packs for under $10. I needed two sizes to re-shim since two of the four in the bike could be used for other valves. I had suggested it could be a possibility to set up a thread for sell/buy of shims by members here. I'd sell the ones I have for a couple bucks and postage, just because. It helps everyone to do so and there is no need to pay for shims you won't use. If nothing else a person doing valves could post a thread for size needed. A shim taped to a piece of paper in an envelope for $2.00 wouldn't be horrible to pay to cover postage and handling.

 

I agree with you, that isn't the problem. It should not make enough difference to make the engine hard starting. 0.01mm is only about 0.0004".

Fact is I have two valves on my Zephyr that are 0.001" (0.025mm) out on the high end of clearance. My shop mechanic friends said if it was their bike they wouldn't bother shimming them for a thou since the job requires pulling the cams (shim under bucket like KLX) so I didn't. Sure if I listen closely I can hear them tick a bit, but I know it isn't damaging.

I'd look at something else, starting with the least costly and difficult part first - the spark plug - if you haven't already. Don't just look at the plug, put in a new one. I had a starting issue with the 650 last summer, plug looked perfect, but there was something bad there. It would bump start and run, but not e-start. New plug good starting. Oddly enough it is even possible for a new plug to be defective, had that happen at times with new ATVs when doing set up, but highly unlikely for two in a row to be bad.

Hope this helps you solve the problem, a simple plug replacement would be a nice easy fix if that could be it.

 

Hope this helps you solve the problem, a simple plug replacement would be a nice easy fix if that could be it.[/QUOTE]
Wouldn't that be nice, but alas I have a box full of new plugs.
Last time the bike did this it was a simple clean out of the fuel injector and a battery charge and off I went. Not so lucky now, with the exact same symptoms. Anyway I do not want to hi jack this thread with my woes, I just needed to confirm 2 things, namely that the valve clearances get tighter with use and secondly being slightly on the loose side with the intakes is not the issue. Correct?

 

Shame it wasn't that easy. Hope you find the gremlin soon.

Your questions -

Yes the main wear is the valves seating into the head, which will decrease clearance. The major "wear" is when the engine is new. After break in the clearance will hold fairly consistent not wearing near as rapid.

The only two wear points are the cam on the cap, which would open up clearance, but is very minimal, and the valves seating or, worse yet, cupping due to heat. Never heard of any sort of valve issues with the KLX, that's usually reserved for the racer types that are trying to run the lightest possible valves. Honda had some problems with the early CRF450Rs.

I cannot authoritatively say that loose valve is not a problem, but considering that the bike won't even bump start I find it hard to believe that a clearance variation equivalent to about 1/8 the thickness of a human hair is the problem. .01mm = .0004" If it was that critical the valve clearance tolerances would not be such a broad range and there'd be a lot more bikes parked by the roadside when their valve clearance hit that point. I've run engines with more than .008" valve clearance without noticeable issues.

The problem has to be elsewhere.