Mixed up buckets on '83 XJ 750 Maxim

FIRST.javascript:emoticon('post', 'message', '')

I want to thank everyone that has helped my son and I complete this project. I have worked on many cars, but few motorcycles. But with all your help; has made this project an fun learning experience with my son.

With that said; I now have a very tough problem to solve.javascript:emoticon('post', 'message', '')

After the reassemble of the engine on my son's 1983 XJ 750 Maxim; he informed me that the first night after tear down. In the morning he found the head had shifted on the box he had put it on and 7 of the buckets fell out. Not knowing the importance of keeping them in their corrosponding hole & not knowing where they came from, he put the buckets back and moved on and said nothing. My Fault for not explaining the process more throughly.

After completing the gasket replacement and engine inspection, the engine had the following compression readings (yes, we triple checked the cam timing) was:
1=50
2= 0
3=0
4=70 - Throttle wide open using the starter.

Note: the engine ran fine, JUST LEAKED A LOT OF OIL. (ONLY 35,000 MILES - 7000 miles since top end overhauled)

I understand from this fourm and other information that the valve to piston clearance is minimal, and it is easy to bend a valve. We took extra care not to force anything during reassembly and cam timing setting and adjustments & I do not believe any valves were bent?

After reviewing the issue with my son, he told me what had happened on the first night before i got involved. And I now believe that our problem (no compression on two cylinders) is that the buckets (& shims) are not in their correct factory location.

My question is:

How do I relocate the correct location of all of the bucket / shim combination?

My son has since gone back to college and I'm trying to get this problem solved, so I can ship his bike (running) to him at college.

ANY HELP WILL BE GREATLY APPRECIATED.javascript:emoticon('post', 'message', ':lol:')

THANK YOU IN ADVANCE.

George,

Sam's Dad

 

Wait, are you saying the engine runs fine, but has 0 compression in two cylinders? Or are you saying it ran fine before you took it apart, and now it has poor compression?
My experience may not be as extensive as others, but I've never had an engine with absolutely no compression on a cylinder. Even with a worn out two stroke with a broken ring Ive never seen anything lower than 30-60psi. How confident are you in your compression gauge?
The other thing, and again my background is not in shim/bucket valves, but as long as nothing is binding in the valve train, having the buckets in different valve pockets shouldn't have much of an impact. I mean, they just provide a stabilized platform for the shim to press down on the valve stem.

 

The compression gauge is old, but I am not sure I can readily quantify my confidence in it. The bike ran ok (but not great) before taking everything apart, mostly it just leaked a lot of oil.

 

There is no way your engine would "run ok" with no compression on two cylinders.

PLease repeat the compression test with a gauge known to be accurate.

 

Sorry I am not being completely clear. The bike has not run AT ALL since the engine rebuild. It did run okay before taking everything apart.

 

Please let me clear up some confusion.

The orginal problem with this engine was an excessive oil leak. The engine ran fine, idle with no issues.

But after tear down and reassemble and mixing up the buckets. The engine did NOT run, zero compression in 2 & 3 cylinders.

SORRY FOR THE CONFUSION.

 

The buckets are interchangeable, and should not cause loss of compression.

The critically important part are the shims. If the shims are all mixed up. Your valve clearances may be holding a valve off the seat.
You will need to recheck the clearances to make sure they are set to spec.

Ghost

 

CORRECTION/CLEARIFICATION

FIRST.javascript:emoticon('post', 'message', '')

I want to thank everyone that has helped my son and I complete this project. I have worked on many cars, but few motorcycles. But with all your help; has made this project an fun learning experience with my son.

With that said; I now have a very tough problem to solve.javascript:emoticon('post', 'message', '')


THE ENGINE RAN FINE BEFORE TEAR DOWN; EXCEPT LEAKED OIL EXCESSIVELY

After the reassemble of the engine on my son's 1983 XJ 750 Maxim; he informed me that the first night after tear down. In the morning he found the head had shifted on the box he had put it on and 7 of the buckets fell out. Not knowing the importance of keeping them in their corrosponding hole & not knowing where they came from, he put the buckets back and moved on and said nothing. My Fault for not explaining the process more throughly.

After completing the gasket replacement and engine inspection, the engine had the following compression readings (yes, we triple checked the cam timing) was:
1= 50
2= 0
3= 0
4= 70

- Throttle wide open using the starter.


***********************************************
***********************************************

Note: the engine ran fine BEFORE THE TEAR DOWN, JUST LEAKED A LOT OF OIL. (ONLY 35,000 MILES - 7000 miles since top end overhauled)

***********************************************
***********************************************
I understand from this fourm and other information that the valve to piston clearance is minimal, and it is easy to bend a valve. We took extra care not to force anything during reassembly and cam timing setting and adjustments & I do not believe any valves were bent?

After reviewing the issue with my son, he told me what had happened on the first night before i got involved. And I now believe that our problem (no compression on two cylinders) is that the buckets (& shims) are not in their correct factory location.

My question is:

How do I relocate the correct location of all of the bucket / shim combination?

My son has since gone back to college and I'm trying to get this problem solved, so I can ship his bike (running) to him at college.

ANY HELP WILL BE GREATLY APPRECIATED.javascript:emoticon('post', 'message', ':lol:')

THANK YOU IN ADVANCE.

George,

Sam's Dad

 

+1 on MiGhost's comment. Don't worry about the buckets. But if you didn't adjust the valve clearances after the mix-up, you'll have to do that now.

Here's an excellent detailed writeup of how to do it: http://xjbikes.com/Forums/viewtopic/t=14827/

 

Where was the oil leaking from at first?

 

I keep seeing "bucket/shim combination."

While always a good idea to get the buckets back in their original holes, it's not critical as long as none of them are binding.

What IS critical, as above, are the valve clearances. If you kept the buckets/shims together and swapped them around, it's VERY likely that one or more are now horribly out of spec.

Just go through and check the valve clearances; and fix the errant ones.

 

Since I know the shims are mixed up, and since I don't have the bucket tool.
Is there any problem with just removing the cams to access all of the shims at once, rearrange and reinstall the cams, reset cam timing and recheck clearanace.

Is there any reason not to use the above method to find all shim values?

What i was wondering was that If I measure valve cam lobe to bucket shim clearance before removing the cams (to find out shim value) and with this value calculate which location each shim should be, then install the cams and complete the valve adjustment.

 

That would work just fine. Be sure to make a chart so you keep everything clear as where to move which shim.

 

Not having "the tool" won't prevent you from re-shimming without pulling the cams again.

See: http://xjbikes.com/Forums/viewtopic/t=29209.html

 

Yeah, buckets can swap around. you MUST get the shim clearances checked, though I DOUBT that is the root of the problem, so get clearances re-spec'd, and we'll go from there....

Dave

 

is there a reason you want to take the cams out and do it the hard way?
if you strip one of those bolts, your in a world of hurt