Lucille pulls another one on me....

MaxPete

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Hi all:

Jim has kindly offered to post an amateur video of an odd new noise that my 1976 C-model began making last night after a spirited ride.

She starts and runs fine - but there is a rapping / knocking sound that I’m sure wasn’t there before. This morning I adjusted the timing chain and the valves (the RH exhaust was a bit loose - but not excessively). I then did a head re-torque, which went fine.

....but, the noise is still there.

EDIT on January 13/2022

Jim’s post of the clip has somehow disappeared so I am coming back to re-post the engine noise clips that were recorded in August 2018:



Long story short - this is the sound of a front timing chain guide that has lost the plastic chain slider. The chain is now slapping against the metal guide “shoe” making a nasty noise. What follows is the diagnosis and repair of the problem and a lengthy discussion of chain guides sourced from various providers including MikesXS and some used parts.
 
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Thanks Jim!

So folks, aside from making you airsick, what do you think of that video? I was trying get sounds from all around the bike while keeping it short.

To my ears, the noise is up high in the engine - in the head, but maybe I’m just hearing things.

Any thoughts / comments?
 
Yeah, Pete, doesn't sound good.
At an idle speed of about 1200rpms, camshaft sounds will be about 10hz, about what your sound is. Reminds me of "flat tappet", when a hydraulic lifter fails.

Take your mechanics stethoscope,
MechanicsStethoscope.jpg

And probe the top of the camcover, where the rocker shafts fit. The outer probe points, marked "probe1" (in red), will be easy to reach. The inner points, probe2 (in purple), may be more difficult.
(Camcover pic courtesy of Robinc)
Robinc-CamCover01b.jpg


You'll hear the sound at all these points, you'll want to find which is the loudest.

Once found, pull the valvecover, and flashlight inspect in there. Check the springs, the tappet end, the valve tip, and (deep inside) the cam lobe. You can slowly rotate the engine to see all of the lobe surface. You're looking for scuff marks and discoloration. Report back.

Edit: Here's a pic of a really bad adjuster tip.
CrateredTip02.jpg

And, a pic of good adjusters.
gggGary-9mm-tappets.jpg
 
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Thanks for the suggestions 2M - say, can I get that cam cover off with the engine in the bike?

Coincidentally, I just got a stethoscope at Harbor Fright the other day and in anticipation of top end jobs on my two bikes, I picked up two sets of elephants feet adjusters a few weeks back.

Karma - lovely. :redface:
 
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The Kedo adjusters are still showing up on Ebay UK and USA. They are still just marketed for XT500, TT500 and SR500. The name Kedo is not always used in the description. If you searched "Kedo Valve Adjuster Ball" they will come up.
 
How do you feel about the VW elephants feet adjusters from Aircooled Specialties?
 
Hmmmm....I'll have a look at them. I thought the shoulder was OK - and I tend to notice stress raisers like that.
 
I have heard that sound before in the Guzzi world. Sounds a lot like a flat tappet "knock" as it rides the cam.

No tappets here (persae) but you may also want to look at the cam contact surface of the rocker. Hardening may be starting to wear. That knock seemed a lot louder than just an adjuster but the video can be deceiving. Tell tale is having to adjust the valves more frequently.

Still not 100% up to speed on this particular engine so I could be just puffing smoke, but that noise, I have heard before.
 
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Probably not the main issue here but there is a problem with your order of adjustments. You adjusted the timing chain, valves, then retorqued head.

Should have been, retorque head, adjust timing chain, then valves. Maybe revisit the chain, then valves.

Scott
 
The concerning part to me Pete, is you said it started suddenly. That doesn't really point to an adjustment problem. That usually indicates a failure of some sort.
 
Probably not the main issue here but there is a problem with your order of adjustments. You adjusted the timing chain, valves, then retorqued head.

Should have been, retorque head, adjust timing chain, then valves. Maybe revisit the chain, then valves.

Scott

Yup - you're correct Scott - that order would have been better. However, that isn't the central issue here.

Dammit.
 
The concerning part to me Pete, is you said it started suddenly. That doesn't really point to an adjustment problem. That usually indicates a failure of some sort.

YES - that sort of points to a broken inner spring or something like that. It was fine until suddenly, it wasn't fine. My instincts are suggesting a broken component rather than a worn out one (its a fine distinction I know). Anyhow - we'll see.
 
YES - that sort of points to a broken inner spring or something like that. It was fine until suddenly, it wasn't fine. My instincts are suggesting a broken component rather than a worn out one (its a fine distinction I know). Anyhow - we'll see.

Hi Pete,
my late lamented father-in-law claimed he could get another 5,000 miles out of his Hillman Minx engine after it started to rattle like that,
just by turning his hearing aid off when he drove.
But you know you gotta pull Lucilles engine eh
 
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