78 XS650 Whirring sound

[clegg]

Had the cam mounted for this one. I forgot to pull the plug leads but admire how easily it starts with no oil.

 

[member28833]

Open an exhaust valve cover, if you look in you can see some of the cam faces, how do they look?

Oh Ya, that is a simple inspection to look at the cam lobes. Good idea. Here is a burnt up exhaust lobe example

 

[clegg]

@gggGary -it’s not rtv, it’s hard like some kind of epoxy.
Cam pics

 

[clegg]

The lobes do look “not good”!

 

[Jan_P]

The lobes do look “not good”!

Looks blue for a 5000 miles Machine ..but should it not have a more Varying sound if that was the source since the cam is not loaded all the time
because of the valve clearance

 

[650Skull]

Is the rocker cover misaligned..........??

Looks like they could me mismatched. Check the serial nos on the front. Should be the same

 

[Jim]

Looks like the clutch basket isn't running true. Bent basket or transmission shaft? Can't tell on the crank. Book limit is .002". That's hard to see in person, let alone on a video.

 

[650Skull]

Agree on the basket not looking good............longer vids would help.

 

[member28833]

..but should it not have a more Varying sound if that was the source since the cam is not loaded all the time
because of the valve clearance

The back side of this cam lobe looks even worse than the lobe faces as I suspect all clearance was down to zero and less in this example. Didn't hear this engine die. Just found this upon disassembly. I can imagine this as bring a steady noise. Awful too lol

 

[clegg]

@skull-I didn't even know there were serial #'s on there. They do match 3E98 on both. The LH side fit looks worse than the RH side.
@Jim-I did notice a bit of clutch wobble.

I'll get a longer vid.

 

[Jim]

@skull-I didn't even know there were serial #'s on there. They do match 3E98 on both. The LH side fit looks worse than the RH side.
@Jim-I did notice a bit of clutch wobble.

I'll get a longer vid.

Take the plugs out and spin it with the starter. Running is too fast to see the crank gear.

 

[xjwmx]

In the running w/o a cover vid I don't hear the whine. Is the tach or cable bound up somehow? Scarring inside the cover anywhere, on the off chance?

 

[clegg]

I removed the tach cable yesterday to check that, It still had the noise.. In the vid was running on one cylinder. I forgot the one was still attached.. update. I just went out and started with the LS cover off. At idle the sound is not as apparent as when revved.
No scarring inside the RH cover..
Another vid of the clutch and crank just turning with the starter.

 

[clegg]

I think the digital imaging makes the clutch basket look to have runout, but in person nothing unusual.

 

[clegg]

Scarring? Actually look at this.

 

[GLJ]

Just my opinion. From your pics of the cam I would be pulling the engine. Plus the rubber you found indicates a bad guide. While you have have the engine out and the top end apart you can check into the crank.

 

[xjwmx]

Scarring? Actually look at this.

It's interesting. I know it sounds better running with the cover off and no oil . Are there corresponding marks on the clutcht? The clutch might be put together wrong. Plenty of good information on here about clutch parts and order of assembly.

 

[Jan_P]

Thinking out loud
Is it the same listening on both sides of machine
If the cam lobe looks like that after 5000 miles .
It indicates poor lubrication.. At some point in time ---Perhaps to little oil
What is likely to happen at other points in the engine.
Can the oil feed clog if bike is not used ?
Can it be the oil pump drive shaft ?
I would assume in the top end
Cam bearing ?
I once had a worn crank bearing with a come and go Noise Sometimes not there and at other times obvious.
I ve had cam lobes looking bad not sounding like that.
Top con rod pin blue not sounding like that.
I ve had a Cam bearing worn so the balls almost fell out Not that sound
Markings on the cover inside i ve also had :Much more than that and only hitting with clutch handle pulled in.
Cam bearing ? that one spins all the time ..even sound
What do experts think

 

[xjwmx]

If it sounds better with the cover off because the oil pump has a problem it could explain the blue cam

 

[thuban]

This kinda stuff is zactly why I got me one of them Doctor stealthoscopies!

It's got a probe on the end and everything. (Not the probe the aliens use on you!)