Changed 5 valve shims and now I have a knock!

I have been slowly working to get my 81 xj550 back on the road, but I just hit another roadblock. Following the advice of this forum, I made a pretty daunting list of things I need to do to it to get it roadworthy. Last week I changed 5 out of spec valve shims.
After getting the job done, and thinking to myself that I did a damn fine job, I put her back together and fired it up. It ran for about 10-15 sec and died (not unusual, she's usually pretty cold blooded) but when I started cranking to fire it back up again it started knocking.... loudly
Anybody have any clue as to what I may be dealing with? I'm starting to think I may be in over my head.
I know that you're going to ask me for more input so I'll just wait for the questions, because I honestly don't know where to start.

Thanks in advance for any help you may have.

 

Re: Changed 5 valve shims and now a have a knock!

Start with a compression test and a re-check of the valve adjustments. Since it was your first time its possible one is way out.

 

Re: Changed 5 valve shims and now a have a knock!

i would check valves first, and i assume you didnt mess with the cam's when you replaced the shims at all?

also depends on where the knock is coming from too.

 

Re: Changed 5 valve shims and now a have a knock!

Thanks for the quick replies guys. When I get home tonight I plan on pulling the valve cover and re-checking them all. I didn't do anything with the cams while I was in there. I followed Fitz's write-up to a T.
I don't really see how I could have messed anything up, but in all honesty the whole job was new territory to me.
Is it really possible that a very out of spec shim could cause a loud knock? that gives me hope that it's not too serious.

 

or possiably dropped a small screw somewhere inside?
just depends on what kind of knock it is and im sure fitz will chim in soon for you as well.

 

Maybe you have a shim that didn't fully seat in the bucket. I got some shims from the dealer that wouldn't even fit in the bucket.

 

I would think some debris got in there, zombiehouse has a good point too. if its coming from the bottom of the motor, its probably not good, I would assume some debris circulated down the oil passages.

if the knock is coming from the top of the engine I would first do a visual inspection of the buckets. make sure the shims are seated and look for any crap that might have gotten in there. maybe. Chipped screwdriver from prying the shimsout? Hell, I hear junebugs like to fly into open engines, lol. seen it before.

if there's nothing obvious wrong ide do a visual inspection of the lobes. turn the engine slowly and watch the cams, see if they hang up anywhere. if they're scarred real bad that's a good indicator that something is floating around in there that shouldn't be. its also an indicator that you need a new cam. : /

if it hangs up real bad somewhere while turning, check for debris again, then check the clearances on the valves that might be causing it to hang up.

Nothing yet? Ide go recheck ALL the clearances.

Im no fitz, but this is what I would do in your situation.

 

Apparently I'm going crazy.

Saturday morning I decided to figure out my knocking issue. Before taking the valve cover back off, I decided to crank it a couple times to try and see if I can tell where the knock was coming from.
I put my head next to the engine and gave it a couple cranks. It turned over 2-3 times with no knock and then fired up with....... no knock :?

I ran it for a few minutes with no strange sounds or knocks what so ever. it sounds great. WTF?!?! I know what I heard the other day and it was definitely a knock. and a pretty loud one.

Anybody have an idea of what may be happening? I'm hoping that maybe it was just a poorly seated shim that has since settled. Or maybe something similar? I don't know if I should just shrug it off or worry about it.

Thoughts?

 

Couple real simple questions:

Does this bike have a centerstand?

How much time does it spend on the sidestand?

If there's even a possibility that you had a shim that wasn't seated properly, I would pop the valve cover and re-check all the clearances just to be sure.

 

When something is not right after performing Maintenance, ... especially if you have a Knock ... retrace your steps to see if you did or didn't do something to contribute to the problem.

Pull the Cover and check the Shims.
Make sure you didn't leave a Shim or a Socket behind.
(Oh, ... yea. It's been done.)

Do it for Peace of Mind.
You might be just checking it out for nothing.
But, you never really know until you look.