kinda stuck valve...

[Shockman54]

so i was adjusting the shims on the valves to get them all within spec, and the #4 exhaust valve is stuck. it will rotate if i take a screwdriver and bump it with my hand, (i assume i couldn't make it any worse, but i was still pretty careful...) but it will not go up or down. there was no clearance on the valve when the cams were on, and it will go down and come back up (using the cams to push it down),but it will not come out or rotate as easily as the other valve buckets. anyone have an idea as to whats causing this? and will it be a serious problem when riding?

[DGXSER]

There is something in there causing it to bind. That somethign is going to wear a groove of some sort into the bucket and eventually that bucket will bind up and no longer move for the cam eigther. In which case it will probably get mashed down and stuck open, getting hit by a piston, causing untold horror.

Obviously, I would suggest getting it out of there some how. As to how, try a very strong magnet. Or a suction device of some type. Otherwise you may need to drill a hole in the bucket and put a screw or toggle down into it to pull it out.

[Shockman54]

i assume i have to get the bucket from the same year engine?

[BA80]

Before you go destroying it, try spraying some brake cleaner or carb cleaner in around it and work it a little. It's probably just gummed up.

[Jeff Pattee]

sticky wicket

If u just finished the rebuild, I assume that u ground the valves. Over time the exhaust valves build up carbon, therefore when u reshim it as part of a tune-up u are adding thicker and thicker shims. The reverse happens with the intake, as they tend to pound into the head. So, if u installed the same shims after the rebuild, the gaps would be small to none....The cam followers can be finicky at times. they were designed to a very close tolerance and they go into the head quite a ways, as u know. I have had to use two magnets to get one out before and be sure that u are pulling them straight out. I assume that u want to take them out just for inspection. A couple shots of carb spray between the cam follower and the head should wash out the 30wt. then follow with something like PB Blaster to penetrate and give it a light oil. Keep working it around and it may come loose.....It wouldn't hurt to put the cams back on and take it to a fully open position to inspect the bore.............but it is probably nothing to really worry about...just reshim and oil it up, and go!! Take a compression reading as soon as u can just to make sure that things are working properly..

[Shockman54]

well, one reason i think its bad is the bucket looks like its lower than all of the other ones. i assume thats bad. and can i use the buckets from my 81 special on my 79?

[skids]

Will the shim bucket rotate? If so, you likely have a bent valve stem.

[Shockman54]

is there something in the forums that cover repairing that? or am i SOL?

[BA80]

Will the shim bucket rotate? If so, you likely have a bent valve stem.

It's SUPPOSED to rotate.

[Shockman54]

the bucket will only rotate if i take a screwdriver and tap it with the heel of my palm. its definitely a little bit lower than any other valve bucket...

[BA80]

I'm thinking you might have a broken valve spring in there binding things up. You'll most definitly need to get that bucket out of there.

Will it turn easier one way than the other? If it is a broken spring it probably will.

I think drilling a hole in that hardened steel may prove to be next to impossible.

You should be able to pull the plug out and feel around in there with something and see if the valve is open, if it is you just may be able to get something in there and push up on the valve and raise the bucket up enough so you can get ahold of it with something.

You follow me?

[Shockman54]

@BA80, its prettymuch the same both ways, it just depends on the angle of the screwdriver... and i follow you, i'll try to get it out that way, no sense in drilling the bucket if that may not be the bad part

[James England]

It's SUPPOSED to rotate.

Agreed. They are supposed to rotate. Rotating is not at all a sign of a bent valve.

I have found that the buckets need to be introduced into the bore absolutely straight. On scrap engines I've messed about with, I found that even the slightest piece of dirt, flake of rust etc in the bore can be enough to either stop the cam bucket going into the bore, or make it sticky in operation. They can also be very sticky when they are a very exact fit and covered in oil (like a partial vacuum effect that stops the shims coming out sometimes).

I've found that it's best to remove the shim and then rotate the bucket by using the shim removal slot and, at the same time, use a pair of long-nosed pliers pulled open, to grip the bucket and pull it up.You have to get all the oil off the top of the bucket to do this though.......

There is, IMO, very little chance of drilling through the bucket. They are incredibly hard

You definitely need to accompany any pulling of the bucket with a rotation of it at the same time. Rotate it only a little but clockwise and anticlockwise... that often works for me

[ViperRon]

+1 on what James and others wrote the bucket must rotate and what James said about removal. One other thing that can cause a problem is the buckets can easily get bent when they are out of the bike to where they are egg shaped and rub the sides. Some times you can by hand force it back into shape but whatever the case it must rotate freely. The swipe of the cam rotates the bucket which slowly rotates the vales in normal operation. If the bucket does not spin there is more chance of a valve burning.

[LuckyEddie]

Kinda Stuck....

I do not know if this will work for you or not but.... with a slight downward pressure with your finger to keep things from getting cocked, try a shot of compressed air at the edge to pop it out.
Now, before railing on me about the hairbrained idea, keep in mind that I often think outside the box. Sometimes it works, sometimes it does not.