Head rebuild - can't get buckets/tappets back over valve springs

[badguy]

I had some valve work done and finally got a chance to put things back together. It was going fine until I went to drop the buckets back into the head, and I can't get them in.

It seems as though they're way too tight to fit in over the valves and springs. I tried sticking the buckets in the freezer, thinking that might help, but no luck.

Anybody ever have this problem?

[DoD#i]

While I have not done this on a GS, my first question is did you keep the parts organized, so that you are putting the same bucket into the place it came out of, or are they now randomized?

[badguy]

That was quick!

Yep, I kept the parts separated and arranged the way they came out. I've tried two so far (intake and exhaust on the right side...these valves are still stock and haven't been messed with) and even tried them on other valves to see if I had somehow mixed something up. No luck.

[saxman]

I've had the head apart and back together many times and have issues with this every single time. What happens is the bucket binds up a bit. What you have to do is just keep working with it, slowly and gently. Try rotating the bucket as you try to slide it into place. It will eventually just drop into place. I'm yet to find an easy, repeatable way to make it work every time.

[The Buddha]

I think the spring gets into a different position when you remove the collets. Its actually easier to open the valve and hold it open while you drop the bucket in the hole, Then gently let the valve out while holding the bucket in place and rotating it and the valve for good measure.
That's how I've seen the engine shop guys do it.
Cool.
Buddha.

[gsJack]

I've had the head apart and back together many times and have issues with this every single time. What happens is the bucket binds up a bit. What you have to do is just keep working with it, slowly and gently. Try rotating the bucket as you try to slide it into place. It will eventually just drop into place. I'm yet to find an easy, repeatable way to make it work every time.

Yep, that's probably it.  Much like putting a piston back into a brake caliper, the very close fit wants to bind it locking it up with the slightest tipping to one side or the other.  Needs a light gentle touch to get it into where there is enough bore engagement to guide it straight.  Muscles no good for this, maybe you can find a little old lady to start them in for you.   

[sledge]

leave em in the freezer the night before 

[Jared]

Yeah they can be a PITA.........pop them in the freezer for an hour or two like Sledge  said...might give you just enough tolerance to get them back in.

They do tend to bind... some will drop right in...some will give you momentary Tourette's syndrome...

[badguy]

Sweet, thanks guys. I'll see if I can get my grandma to come over and try it again later

[badguy]

So I got em in the other day (warmed the head up in the oven ) and put the camshafts back on tonight after I got the timing all set up. As I'm turning the engine over, I notice while looking through the intake port that it seems as though the exhaust valve is open. I look up at the cam and neither exhaust valve is closing all the way. On the left cylinder, there's about 5mm between the shim and the 'closed' part of the cam lobe The right cylinder isn't as bad.



I noticed that the exhaust valves are swapped - the old valve from the right cylinder is now in the left cylinder and the brand new valve (I bought to replace the bent left valve) is in the right cylinder. I can't see how this would be a problem though.

Crap.

[The Buddha]

Yea clueless clowns end up taking too much material off the seats and seating faces of the valves when cutting them. You can compensate by taking material off the top of the valve, however, do too much of any of those, and its toast, BTW the fool that did that machine work needs to be dragged out into the street and beaten.

The first run I did with the clowns that I do machine work with was with a dead savage head. I told them if they screw it up, I am not paying them and matter of fact I am not even comming back there. If they got it right, not only will I pay for the dead head - I told em it was dead, cos it was beat to hell from a busted valve. They not only managed to get it machined right, they also surfaced the head by hand, cc'ed it right - so I can use it if I wanted to ... But I can tell you its a fine balancing act. You want the 3 angles cut right without losing more than a few 100th's, then you take off a few 100ths off the top of teh valve stem and you're nearly back to your starting point. Now car junk is built rather sloppily, cos they fit and can even custom machine shims and lifters, and they never have to be adjusted, they are all hydraulic, it can cover fine for a good 1/2 inch prolly. Bike stuff is usually measured in the 10,000 th's. If you dont have the precise equipment, you will never get it right. In car shops they have what are called "engine room lathes". Bike work needs to be done on what is called a "tool makers lathe".

I know of one guy who spent 2 years rebuilding the pair of tooling lathes from the 40's and 50's. Looked immaculate when he was done. He said he used his new lathe to build it, and 3/4 of the way through, he had to use the tool lathe to rebuild itself. Weird, but he said it was the only way. 

Cool.
Buddha.

[badguy]

Are you saying that he took too much material off the valve seat and the valve stem won't allow it to seat against the head?

If so, I don't think that's the case - if you look at the picture, the bucket won't return to the cam lobe...if what you said is true, I'd think the valve would follow the cam as usual, but there would always be a gap between the valve and the seat. As it is, there's a huge gap between the shim and the cam lobe. It seems as though the exhaust buckets are getting stuck or the valves are binding in the guides

[The Buddha]

Sorry cant see the pics from work.
But, your description - and I guess you said it backwards, your valve is closing, but not getting to where it contacts - or gets with in a couple 1000's of the cam.
Now that - exact opposite problem, valve appears too short. I doubt they too too much material off the valve stem. You have anything else going on - excess wear on the cam ? Maybe your cams are not in the head all the way ? I am not sure what can that be due to.

Cool.
Buddha.

[gsJack]

That's right badguy, if too much was ground from the valve and/or seat there would be a problem with too little or no clearance and not too much clearance.  Looks like a sticking bucket or a bent valve holding the valve open, if you had to heat the head in the oven to get the buckets in I would be guessing you have sticking buckets unless there's some way they could have screwed up the valve seal to cause binding of the valve in the guide.

I had a sticking bucket on my 02 GS for 20k miles and it really didn't cause me a problem until I tried starting the bike one freezing morning and the exhaust valve stuck open even more and broke off the valve.  I replace the broken valve and sticking bucket and lapped in the valves to make sure they turned free and had good valve seal.

Are you working out in the cold?  It makes the buckets tighter the colder it gets since the aluminum head contracts greater than the steel buckets as the temps drop.  That's why I got away with it for 20k miles before breaking a valve that very cold morning.  Bike would start up in normal temps and run rough for 30-60 seconds until the head heated a bit and freed the sticking bucket and it ran good after that.  I kept hoping the bucket would wear in and free up without tearing it apart, it didn't.

When you said above that you looked into the intake port and saw the open exhaust valve I assume you meant you were looking into the exhaust port?  If you can't turn the buckets on the assembled engine with valve clearance with your finger tip at normal room temps you are going to have sticking bucket problems in my opinion.

[badguy]

Buddha - You're still missing a bit of the picture: the valve is not seating AND the bucket+shim is not coming within even 5mm of the cam lobe. I guess it's possible that the camshaft isn't seated fully, but I'm 99.9% sure I have it seated properly.

Jack - I'm working in my living room, so about 67*F. I think I'd have to agree with you that it's a problem with the bucket sticking, as I cannot turn either of the exhaust buckets with my finger. I haven't tried the intake buckets. I was indeed looking through the intake port at the exhaust valve - the intake valve was open so I could see into the combustion chamber, and there I saw the exhaust port sticking down a bit. I'll try to get a picture when I get home.

Thanks for the help fellas Now I just have to figure out my next move.

[The Buddha]

Well, take off the bucket and see if it would seat ... how hard is it going to be to get it off ? I dunno but its gotta come off else you in big trouble. You should not be stuffing things in without thinking how its gonna come out or move around. I was working on this fool's rear wheel one time, and he stuffed a brake drum with the wrong shoes in it. WTF, if you're having to hammer in a part that is eventually going to rotate free you're stuffing yourself.
Anyway you need to get it out, make sure it closes, then get it fitted properly, then worry about fitting the cams in.
Cool.
Buddha.

[badguy]

Well, I figured I needed to heat it up to get the buckets out (and it was running until the one valve got stuck) so it shouldn't hurt to heat it to stick the buckets back in. When I set them in the other day, they all slid in nicely once they got started...but I couldn't start them while the head was cool.

I guess I'll pull it apart again.

[badguy]

Well, bought a new head since the old one was giving me fits. It ended up costing less than half the amount I had already sunk into the original head Another lesson learned the hard way.

I still need to get a battery and fix up the bodywork, but she's running:

http://www.youtube.com/watch?v=g9M-oFrX1_w