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Discussion Starter #1
Once again I decided to adjust the valves on my TW to try to eliminate a horrible ticking sound. On the intake the .002 feeler gauge was loose, the .003 was snug, and the .004 was tight. I was in the ball park! Then I removed the feeler gauge and I put my finger on the rocker arm and it moved up and down somewhere between 1/32" and 1/64". Long story short I decided to take it apart and see what was going on.



This is the adjusting screw. It is a little blurry but I think it shows that the end is fairly banged up and convex in shape.







This is the end of the valve stem. Clearly it is concave. The feeler gauge was bridging the concavity giving a very false reading.







The adjusting screw now sits deep in the lock nut. I think a new screw and valve are in order sometime in the near future. (The bummer is I just had the head off to replace the base gasket!)







A human hair is .0025" in diameter. The minimum intake valve clearance is slightly less than the diameter of a human hair, .002". So the moral of the story is when done adjusting your valves give the rocker arm a little shake. If it moves more than a teeny tiny little bit something is wrong and it should be investigated.
 

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Thanks for the tip, Tony.



I'm due for a valve adjustment, and will give he adjusting screw and valve stem a close inspection.



How many miles are on your TW?



Jb
 

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Discussion Starter #4
How many miles are on your TW?


Just over 20,000 miles but that dang ticking has been going of for at least the last 10,000 miles.



At first it wasn't so bad, I could adjust the valves and it would almost go away. As time went on no amount of valve adjusting, that is adjusting using a feeler gauge, did any good so I assumed it was something else. Then the other day I adjusted the valves once again, I removed the feeler gauge and wiggled the rocker arm and it moved a lot. I put the .003 feeler gauge back in and it didn't wiggle at all. The light bulb finally came on saying something was wrong. I took it apart and found what the pictures show. DUH! I wish I had figured it out a long time ago.



Since the feeler gauge is pretty much useless with a concavity in the end of the valve I adjusted the clearance using the "feel" method. Simply I grabbed the rocker arm and wiggled it and could feel a teeny tiny bit of clearance. Remember the width of a hair is the minimum you need and I have at least that plus the loud TICK TICK TICK is gone so I feel good.



Next step is buy a new valve, adjusting screw and head gasket and go at it. I sure wish I could reuse the head gasket. I hate paying another $17 for something I just installed last week during the base gasket replacement.
 

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So, the end of the adjuster (banged up end) and the top of the valve stem (concave end) should be flat with each other, and not concave/convex as shown in your pictures, correct?
 

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Discussion Starter #6
So, the end of the adjuster (banged up end) and the top of the valve stem (concave end) should be flat with each other, and not concave/convex as shown in your pictures, correct?


The end of the valve should be flat and I am pretty sure the adjuster is slightly convex. When I get some new ones I will post pictures -- if I remember.
 

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Just an FYI for anyone who comes across this:



http://tw200forum.com/index.php?/topic/2514-valve-adjusters-intake-valve-died-who-fights-next/page__view__findpost__p__22260__hl__+valve++adjuster__fromsearch__1



If you find yourself with an adjuster screw that looks like its worn, REPLACE IT! (they're cheap!) The contact surface is clearly hardened, but the metal underneath does not appear to be, and once that hardened surface wears away, the job gets much more involved.. and the language in the shop more colorful.



EDIT: modified advice, inspect very carefully. If both the screw and the valve are worn, you waited too long to adjust the valves, and you best plan for some time to replace both parts, and the requisite other pieces. Lest you end up in the same leaky boat Tony and I have been in!
 

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Reminds me I need to do this job. Are there any special tools needed?
 

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Reminds me I need to do this job. Are there any special tools needed?


You will need a square drive socket to hold the adjusting screw....or use a square drive deck screw and a small vise grip like me. Check the pinned valve adjustment thread for details. The torque on the lock nut is pretty tight and I would not do this by feel. Tighten with box end wrench while holding screw, then final torque with torque wrench and recheck for possible change in clearance. I could never get my torque wrench on the carb side, so I did the exhaust first and remembered the feel while gripping the box end wrench at the same distance from center.



I'd do it about every 4,000 miles or two years.
 

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Discussion Starter #13
After 75 miles of use I decided to look at the adjusting screw that looked so bad in the beginning. To my surprise, after grinding away the rough edges and lightly polishing with a rubber wheel using a Dremel plus 75 miles of use, it had polished itself to a mirror like finish. Not perfect or new but much better than when I first saw it.







The one on the far left is the same one as above. I just had to use the rubber wheel on it again so it looks a little worse that it really is. The two in the middle came from my parts bike and were replaced with new ones. The one on the far right is a new one and is destined to replace the one on the far left when ever I get around to changing the valve.







If I were only adjusting the valves and didn't have the head all apart, I think now I would simply polish the screws with a rubber wheel and go on using them. I bet they would work just fine, at least until I got around to getting new ones or the next time I adjusted the valves.



What the end of a new valve looks like. Someday soon I will install it.



 

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Discussion Starter #14
I replaced the intake valve that was causing me so much trouble. I was worried that there was so much wear that: 1) it might fail some where far from home, 2) that it might cause the valve guide to wear out sooner, 3) I wanted to lap the valves anyway, 4) it needed new valve stem seals and 5) a new valve is only $10 (plus $17 for a new head gasket and next time I am reusing the old gasket to see how it works out).



Close up view of the end of the valve. There is a small bump in the center of the hole that is a little hard to see in this picture but shows up nicely in an earlier picture.

I had to file around the edges of the valve stem because it was starting to mushroom and wouldn't fit through the valve guide.

Pliers are there to trick the camera to focus in that area.







Close up of the end of the adjusting screw. There is a small divot that corresponds to the bump in the end of the valve. It seems to have polished itself nicely and may have lasted a while but I was also concerned that as the rocker arm swung through its arc that it would put additional lateral forces on the valve guide and cause it to wear out sooner. New valves are cheaper and easier to install that new guides. I decided to fix it now the easy way!







Another shot of the end of the valve. I laid a straight edge across it to try to give some idea of the depth of the concavity. I measured it with two different calipers and the distance from the bottom of the straight to the top of the bump in the center is approx. .015" . I think fitting the bump into the divot and the actual depth is in the .018 to .020 range. Add .004" clearance that the manual calls for and the total clearance is in the .022" to .024". No wonder it was going TICK TICK TICK!







And here are the valve stem seals. These are 26 years old and the rubber is hard as a rock and barely making any seal at all. These are easy to remove and replace and considering how long they last they should be replaced when the opportunity arises. I think they were about $4 each -- sounds outrageous for what they are but chances are they will only get replaced once or twice in the life of the engine so no big deal.



 

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Thanks for the update.



Jb
 

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Thanks for all the great info Tony. I also have to replace a valve. My jam nut on the intake valve came off this weekend. The valve stem and adjuster beat each other pretty good. I'll try and post pictures later. I also had the base gasket leak so I pulled the cylinder as well only to find my oil ring stuck in the piston. So I got that to take care if as well. My concern is the valves. The book says you have to replace the valve guide any time you change a valve. I don't think I can do it? Should I take it to a machine shop? Or say heck with the guides and just put in new valves and seals? Any advice would be greatly appreciated.
 

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Here are some photos of what I'm dealing with.



Good exhaust valve.





Bad intake valve (stem is mashed)





Left is the intake adjuster right is the exhaust, you can see the damage.





Valves in he head

 

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Discussion Starter #19
I replaced the valve and used the old guide. I put the valve stem in the guide and it wiggled sideways a teeny tiny bit, which is good so there is room for oil. I did have to clean out the inside of the guide very clean because just a speck of anything and it binds up. As long as it is a very close fit I think you will be OK. I have 150 miles on it so far and it runs great!



When you remove the battered valve the end may have mushroomed to the point where it won't fit out the guide. Don't force it. Take a file and go around the edges and it should slip out easily.



Lap the valve, replace the seal, keep everything clean and I bet it will all work out. Other than the scary part of a compressed spring potentially going TWANG and flying across the room the procedure is pretty simple. I think what the manual recommends is for a mechanic working for a customer and doing the absolutely the best possible / perfect job. While apart lap the other valve and replace that seal too.



I used a valve spring compressor for a car head. It was marginal and just barely worked. I had to use washers as spacers. I can't recommend using a car type valve spring compressor. The correct tool would make it a whole lot easier.



It is pretty simple. If you have never done it before it can be a little scary like anything else but once you have done it it becomes no big deal. Good luck.
 

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Discussion Starter #20
Looking at the pictures it looks like the little wedge shaped retainers are cracked. Best to replace them and the valve spring retainer too.



What did you use to clean the piston and everything else? Looks great! Super pictures!



I forgot to say above that the camshaft comes out first then the rocker arms. I tried it the other way around and it doesn't work.
 
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