Reassembled motor...what is that noise? (With Video)

[Fleksta]

I've buttoned my motor back up but there is an odd noise when it is turned over. Every time it passes the TDC mark it makes a metallic "ping" clearly audible in the video.

I had the motor apart to replace a leaking head gasket, and also replaced the cam chain and rear tensioner. I did no other work; pistons went back in as they came out and I didn't touch the valves.

Once back together I adjusted the tensioner and re-adjusted the valves (which were all very tight). I already checked to make sure the copper washer was still on the tensioner assembly.

I'm wondering if this is something to worry about...or just me being paranoid?

The first ping can be heard at the 4 second mark:

 

[TwoManyXS1Bs]

I don't see the valves moving while you're cranking.

Yes, that's not a good 'clank' sound.

Could check to see if anything loose fell into the rotor/stator area.

Otherwise, I'd need another video where I can see the valve(s) moving.
Helps to find my 'mental' position...

 

[I am Carbon]

I don't think your being pranoid.
I would be worried too.
I'm not sure what it is, it sounds spring like too me.
If it was my engine I would figure out what it is before proceding.
But maybe I'm being paranoid.
I agree a look inside while making the noise video would be good

 

[member3480]

That sounds like a valve being slammed closed buy the piston.
DO NOT START IT
Did you remove pistons from rods? If so did you follow the arrow position .
Did you readjust the valves on the wrong stroke?
I would pull it back apart to be safe.

 

[Fleksta]

I'll get the cover off again this evening. I did have the pistons removed but had made sure to label everything and left the inner circlips in place.

I only adjusted the valves after hearing that noise, and it made no difference to my ear.

Could the cam cause that if installed in the wrong orientation? Going back over my notes I'm wondering if I put the drill mark on the top / points side and the cutout horizontal instead of the other way around.

 

[5twins]

You can check for correct cam timing without tearing the whole motor down again using this method .....

http://www.650motorcycles.com/CamTiming2.html

Looking at the ends of your cam will also tell you if you put it in backwards (it's been done). The threaded end with the pin hole should be sticking out the right side of the engine.

 

[Terrible1]

Weird. I'm working on a 1980 XS that's doing the same thing somewhat but a click and not a ping like yourself. I'm wondering what it is too. This motos has never been apart either.

 

[IllusiveJack]

Was this ever solved?

 

[Fleksta]

Looking at the ends of your cam will also tell you if you put it in backwards (it's been done). The threaded end with the pin hole should be sticking out the right side of the engine.

So since the advance unit locating pin was on the proper side and pointed downward, the cam must be in correctly?

 

[IllusiveJack]

When your timing mark is at TDC and the left hand rockers are facing up and not compressed onto the springs, the hole on the threaded side should be facing up.

 

[I am Carbon]

the locating pin is in the 12 oclock position at TDC as Jack as just pointed out

 

[Fleksta]

Ok, I checked that pin again and it is down when the right-side valves are loose.

So I should take the cover off to fix that anyway...but being 180 off shouldn't account for that noise correct?

I watched the valves while turning the motor and it seems to be pinging when either intake valve is pushed down.

 

[IllusiveJack]

If its 180 out then there's a good chance that you may have bent a couple of valves, when you turn it over the valves maybe getting stuck in the guides until the pressure of the cam forces them out "Ping", You wont know this until you take the rocker cover off though.. Just before the ping noise, does it get a little tight when you turn it over? Out of interest, when you put the rocker cover back on, did you loosen all the valves off?

 

[Fleksta]

Darn, figures I'd turn this into an expensive fix.

It might get a little tight, but I'm not sure. I can't seem to feel it binding.

I did not loosen the valves when I put the cover back on.

If it turns out that I managed to bend the intake valves, is it just a matter of buying replacements or will I need to send the head out to get a whole valve job done?

 

[IllusiveJack]

Hi Flek, first thing to do its take it apart, take the head off and check the movement of the valves, if everything looks ok, use a piece of wood or something to push down on the valve springs to see if they are sticking, also check the vales where they seat into the head to make sure there are no visible gaps, if you have a valve spring compressor, it may be worth taking the valves out to check them and re grind them in, if not, when you put the engine back together, go by the book and read the manual and double even triple check everything you're doing, if the vales are bent, then all you need to do is purchase a new or second hand set, but you will need to grind them in before you use them. The valve guides will probably be ok, oh and if you fit new valves, also fit new valve oil seals! Simple mistakes can cost a fortune...

 

[deadchef]

i know this might be a long shot but i had a motor that made that noise before because it was missing the damper washer on the cam chain tensioner rod. caused the spring to bunch up a little and then snap back and make that 'ping' sound.

 

[ippytattoo]

If its 180 out then there's a good chance that you may have bent a couple of valves, when you turn it over the valves maybe getting stuck in the guides until the pressure of the cam forces them out "Ping", You wont know this until you take the rocker cover off though.. Just before the ping noise, does it get a little tight when you turn it over? Out of interest, when you put the rocker cover back on, did you loosen all the valves off?

Jack, on these 360* parallel twins if the cam was installed 180* out there would be no interference because for every 360* of crank travel there is only 180* of cam travel. If it were 90* out there could be a problem.

 

[peanut]

it does sound like a valve spring binding and suddenly being released.

If it were me I would loosen all of the valves completely so that when you turned the engine over none of the cam lobes moved any of the valves and then see if the noise goes away. If it does then you know its valve related

If it doesn't go away then you'll probably need to take the cam cover off to investigate further.

You could use a screwdriver on your ear like a stephoscope and see if you can pin-point which corner of the head the sound is coming from befor you tear it down

 

[IllusiveJack]

Ippy, yeah I see what you mean, we'll have to wait n see when its stripped apart

 

[Fleksta]

it does sound like a valve spring binding and suddenly being released.

If it were me I would loosen all of the valves completely so that when you turned the engine over none of the cam lobes moved any of the valves and then see if the noise goes away. If it does then you know its valve related

I'm sure its coming from the valves, the motor made no noises when I was turning it to check the cam alignment before putting the cover on (which I seem to have botched anyway )

I must have been interpreting some pictures in the manual backward or something

If I installed the pistons mirrored (entirely possible as I put them back into the head upside down and flipped it over to install), with the exhaust cutouts on the intake side could that cause the interference we might be hearing?

I should have time after work today to pull the cover and possibly head off again. I really appreciate everyone helping me think through this