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Valve Adjustment and Shim Exchange?

By tigerowner_ut,
in WR400F/426F/450F

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tigerowner_ut

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After 2.5 light seasons and around 1000-1500 miles I dove in and adjusted my valves. Here are my observations:

1. Anyone can do it if they take their time and watch out for small hidden parts.

2. Why does this have to be such a convoluted process. On my old trusty TT you just pull the cover, check the gap, use the nifty little tool to depress the valve, swap the shim, put it back together, and go. With the WR you have to remove the upper engine brace and valve cover then check the gap. No problem yet. Then if you need to swap a shim you need to remove the carb, cam chain tensioner, cams, lifters... With an extra half hour you could just about do a complete rebuild! Absolutely ridiculous when other competing machines can be adjusted with half the effort. By the way make sure you have a magnet to pull off the lifter before you start. Luckily I found one in my brake bleeder thingy.

3. Why does a single shim smaller than the tip of my pinky cost nearly $8? 30 dollars and 4 shims (lucky I could swap the fifth) later I am putting all the pieces back together.

4. I dropped the chain wheile rotating the cam a tooth. Yes I tied it up while the cams were out but removed the wire while orienting the cam. No biggie, went fishing and recovered the chain with a piece of wire.

5. Who the hell was the engineer who put those clips on the cam. I was damn paranoid about dropping those into the abyss.

6. I wanted to play with my carb needle anyway and this gave me an excuse but why should I have to take off the carb to adjust my valves. Friggin stupid.

I did it. 4 out of five valves were at minimum tolerance and the fifth one was just out. So all five shims were changed. Mid spec on one and close to max on the rest. Bike fired up on first touch of the button and seems to run fine.

Question: Since I am sure that we all have shims we can no longer use can we start a shim exchange here. 35 cents beats $8 anyday and I will ship mine to anyone who needs them FREE but I would like the sam courtesy from others.

I have the following shims:

3 x 178

1 x 180

I will need a bunch of 170s and a 165 after a while.

If you have shims you can't use post them. If you need shims post what you need.

What do you guys think?

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gobigblue

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I think it is an awesome idea but now you have scared the hell out of me about checking my valves. I have never done this before and it now sounds difficult. have you ever done this kind of thing before? I can get my with minor maintenance on vehicles and am comfortable wrenching, but with something this delicate I want to make sure I am not getting in over my head.

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Grand Master

clark4131

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I felt the same way the first time I did my valves. I went so slow and was so methodical about the whole process, it took me 6 hours...which included a trip to buy some shims. After it was all over though, I realized it wasn't a big deal at all. I could probably do the whole thing again in an hour. The manual is invaluable and you'll need a large torque wrench in ft/lbs and a small one in inch/lbs. A couple universal joints can't hurt either. Read the process a couple of times before jumping in. It really isn't that tough...SC

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Matty05

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I think it is an awesome idea but now you have scared the hell out of me about checking my valves. I have never done this before and it now sounds difficult. have you ever done this kind of thing before? I can get my with minor maintenance on vehicles and am comfortable wrenching, but with something this delicate I want to make sure I am not getting in over my head.

Checking the clearances is the easiest thing to do. It takes less than 10 minutes to do. Follow the manual!

It is changing the shims that is the pain in the ass, but thank your lucky stars it is a very rare thing to do on our Yamaha's!

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bcs

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Anyone have a pic of where the shims are placed? How are they secured? The last valve adjustment I did was on a 4 cylinder OHC car engine. So I have the general ideal but I got my first thumper 3 years ago and I've not done valves on a thumper yet.

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Matty05

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Anyone have a pic of where the shims are placed? How are they secured? The last valve adjustment I did was on a 4 cylinder OHC car engine. So I have the general ideal but I got my first thumper 3 years ago and I've not done valves on a thumper yet.

Have you got a yamaha manual???

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tigerowner_ut

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Yes you can check the valve clearances in about 20 minutes at any skill level but the adjustment is a pain. I probably could have avoided removing the carb but the manual says to remove it. I guess if you can turn the carb enough to get the tensioner out then you don't have to remove it but it would be difficult to wind the tensioner while you are installing it with the carb in place.

Shims are secured in a recess on top of the valve under the lifter.

Any thoughts on the shim exchange? It is not like they will ever wear out.

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Grand Master

SoCal WR426

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It is totally unnecessary to remove the carb. Get yourself a little flat bladed screw driver. Little in blade width and little in total lenght and then you can come at it from the rear of the carb and slide it through to the tensioner screw. The hardest part is to access the inboard bolt that holds the tensioner assembly to the engine, but it is still easier than taking the carb off. As to the exchange of shims it seems like a good idea except that my dealer will do that for you. The other thing is I have not really checked the chart that carefully but I don't if you and I have used engines that are wearing normally that if my used shim needs to be replaced by the next shim in the normal progression then you need the same new shim I need and not my old one. I am not sure if that is correct and also don't know if my explanation made sense.

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chancho196

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A couple of wobbly 3/8 extensions are all that's needed to remove the tensioner without moving the carb. The shims that people will need will almost always be different because of different tolerances used when making the head/valves/seats etc. in the first place. The exchange is a fantastic idea. (Just wish I was in the States now!!) Years ago in the UK, shops used to offer an exchange with shims for Suzuki GS road bikes etc. but I doubt very much whether this still goes on.

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