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I have a persistent valve tap on this '84 1200 I'm working on.

It seems like just one rocker is tapping, on the left side, which is quiet until the engine is warmed up then the tap is continuous and pretty loud.

Here's what Ive done to this engine:

Machine shop work:

Cleaned and surfaced heads flat.
Replaced all 4 exhaust guides (intakes were ok).
Replaced all valve seals.
Cam lobes and rockers were pitted, they filled and ground.
Not sure what was done with the valves, most likely they only lapped if anything more than cleaning.

I bled the lifters,
Oil distribution plate holes are clear, I replaced the seals,
Checked shim measurement multiple times, one shim on each valve,
I made sure the rocker shafts and rockers are moving freely,
Ran with valve covers off, it appears to be getting PLENTY of oil,
Compression was 155-160 before the head work, it's now 170 all 4.

It's sluggish until warmed up like it's running lean.
Once warmed up it runs great with smooth idle and plenty of power.

The owner says it did tap on this side but went away after a 1/2 minute or so.

Every cold start ( a 1/2 dozen or so) it's quiet then starts tapping once warmed up.
It acts like one lifter is starving for oil but only when warm, or like something is causing the tappet clearance to increase only when hot but what could that be.

I used 10/30 oil for startup as a flush then changed it to 20/50, tap has been about the same with both oils.


I'm at a loss here,
All suggestions appreciated.
 

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I would leave the valve covers off, and run it until it starts clicking. Then use a stethoscope or long screwdriver to listen to each rocker arm and at least narrow it down to the guilty item.

Then try to figure out what is wrong with just that one part.

One thing you mentioned though that perks my ears.

They welded the cam shaft and reground it. That makes that dude suspect to me.
 

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Makes me wonder if a lifter isnt getting partially stuck in its shaft when the metal expands. like its out of round. If that were the case, honning the lifter guide would possibly cure this issue. Did you inspect the bottom of the lifters for mushrooming?
 

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I would try to pin point the cylinder, could be a guide is a little tight?

If you have to take the head back off I would lap the valves andbe sure it moves freely, spin it and pop it open and closed

Look for a broken valvespring ?
 

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Did you replace the Timing belts? Check that the marks are properly aligned. If they are not it would be a valve hitting the piston, NOT GOOD! The best to you. God Bless.
 

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I had an 85 LTD that did that and I forund some metal shavings (left over from manufacturing) in one of the oil port's.
 

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Discussion Starter · #7 ·
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All good suggestions so far.

Something not moving freely once hot is a possibility.
The rocker shaft has to rotate freely for the adjuster to work properly.

I've been trying to figure a way to isolate which lifter, running with the valve cover off cant do, all the oil would be emptied from the engine in a few seconds.

This thing doesnt have hydraulic lifters , we call them lifters but they are actually hydraulic adjusters. They push on a notch to rotate an out of round lifter shaft which takes up the lash. Alot of moving parts.

I've been starting to suspect the grind but considering the way these adjust and it's complexity, one of the parts getting sticky is entirely possible.
Something changes once hot, it sounds great when cold.
 

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If you could grab a different head for the affected side & swap it, you would find out quickly if it's in the valves or the block. If I had a spare I would mail it to you!
Good luck & I really hope it's nothing thats going to cause you problems!
wayne.
 

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Dan--I have the same concern as Arizona. Did the fellow who filled and ground the cam lobes have the proper specs for the cam shaft, and was it done on a proper machine? Not to suggest that that is the source of the tapping. You seem to have done about everything possible to eliminate the problem.

I am soon going to be dealing with much the same thing on my old 84 that I sold to a local guy. He had the right head gasket blow(I had already done the left side) and now has the tapping noise on the right side. Course, I don't know how much the mech who did the job knew about the engine, but I suspect a blockage in the oil gallery.

Keep us posted.
 

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Only 1 way to find it if itis in a valve system

Loosen one at a time and run it till you find it
 

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Discussion Starter · #11 ·
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I talked to the guy that did the cam grind.

He told me he's done many of these 1200 cams successfully and the grind he did on these is very mild, he called a stage one. I didnt get into any specifics but he said this mild grind wouldnt cause any hydraulic adjuster problems or clearance issues.

I'm not very knowledgeable with cams specs and what effects different grinds will have so I have to trust he knows what he's doing having come highly recommended by the head shop in the business for over 35 years.

I described to him how the tap comes on loud once it's warmed up, he said it sounds like the hydraulic adjuster is bleeding off once it's hot.

I'm going to see if I can figure out which cylinder the tap is coming from with a screw driver to my ear and maybe compare compression taken just before the tap comes on against what compression is when it's tapping.
If I can figure out which cylinder is tapping then by swapping around adjusters I should be able to get the tap to move if the problem is indeed a bad adjuster.
 

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You COULD try removing the shims--perhaps one lifter at a time. It may be possible that, with a new cam grind, theclearances may be beyond the limits of the adjusters.
 

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Discussion Starter · #13 ·
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Good point Hawker.

I've measured all the shims to be one at each valve.
2 valves had 2 shims before the work, tried putting the 2 back. There was no difference but those may not have been the valve that's tapping.
I may pull all the shims and see what happens.
 

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Hi been reading this with interest.



I too have done a rebuild of the valve guides and following rebuild found a tapping after warm up.



Mine is a simple screw and nut adjuster, but found that the exhaust valve in question needed adjusting after 100 miles. It wastoo tight each time.



Following a lot of talking to engineers I opted to leave it alone and see if it got worst.



It didn't and seemed to change in volume when warming up then quiten when fully warm.



The theory i'm following is a guide to tight.



I too didn't lap the valves as time was tight. All work was done by a very good machine shop have no cause to suspect the reaming.



It's not yours so it is hard to say just leave it a while and see if it beds in it self.



There is no change in power or oil loss.
 

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Just read the quotes above again and I would not be one to blame the cam or the work done.



Stage one is a very mild tuning mod and is done to improve overall performance and is certainly not a race mod. Just out of interest was it done to both cams? This need to happen to both to work effectively
 

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Discussion Starter · #16 ·
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goldtop wrote:
Just read the quotes above again and I would not be one to blame the cam or the work done.



Stage one is a very mild tuning mod and is done to improve overall performance and is certainly not a race mod. Just out of interest was it done to both cams? This need to happen to both to work effectively
Yes both cams.
 

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All the suggestions above make sense. I doubt what I am suggesting will be solution, but is more of a suggestion for discussion. I have a 1985 GL1200. I have an occasional lifer noise that comes as the engine is warming or completely warm. Mileage is 83,000. It seldom last more than 15 to 40 seconds in duration. A while back I ran some gunk engine flush before an oil change. The occasional noise stopped for about 100 miles then slowly returned. Twisting the throttle will stop it. I am starting to wonder if it is not just air or moisture that turns to steam passing through the lifter. The lifter does lay on its side. It seems to me this would make it prone to trapping gasses rather than pushing them through quickly. It would be interesting to see if they are prone to trapping air. Does anybody have a drawing of this lifter for examination? This is just my best guess as I have never seen the lifter, but there are plenty of GLs doing this from reading the forums. Any thoughts on horizontal lifters snagging and holding transient air for short durations?
 

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There's a prodedure outlined in the Honda service manual to center the rocker arms. It cured my bike's ticking.
 

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Discussion Starter · #20 ·
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Looks like I found the problem!
It took a combination of all the suggestions.

Dennis clued me into maybe the rocker was not centered, that and it acts like the steel rocker or steel rocker shaft was jamming when it gets hot, possibly due to the steel expanding differently, that was my best guess.

Firstly when it was cold I swapped the adjusters with the other side to see if the noise moves, it didnt.
Then with a screw driver to my ear it was fairly easy to hear the #4 exhaust was the culprit.
While hot I pulled the valve covers and alternator cap, turned the engine til #4 exhaust was fully closed and found it very loose. Once I loosened the cam holder bolt the lash was gone. After removing that bolt and getting the end cap to sit as far away from the rocker as the bolt going thru it would allow, I retorqued all the bolts.
Started it up and ran for a good 10 minutes hot with no tap.

I'll post if the tap comes back after a road test, so far it looks promising.
 
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