K75 Engine noise

[rbm]

it was mentioned.

[daveson]

True. I see that now, but I don't think it's been removed because the video example sounded different to bg's brick.

its an easy thing to try.

[bgcameron]

What work are you planning on doing? Opening the engine? That's a big job. I'd do some tests first to confirm it's the problem before doing that. Has the starter been working normally, does it sometimes slip? The crank could release the clutch, hard to imagine it could engage it.

If he means the starter is turning the clutch, I'd remove power to it (and insulate) and see if the noise disappears.

I am doubtful that it's the starter clutch.. The starter functions as it should. I am going to to the spline service as planned, torque the nut and hope for the best! Hopefully will get around to it next week.. lots on my plate right now.

[daveson]

Good luck.

I'll be keeping an eye out for the result.

[daveson]

I've just cast an optic nerve over the video of the timing chain. Any thoughts out there about the timing marks looking to be a little bit out?

Just a stab in the dark.

[bgcameron]

I've just cast an optic nerve over the video of the timing chain. Any thoughts out there about the timing marks looking to be a little bit out?

Just a stab in the dark.

I think it's the angle of the video. Look at how the holes in the gears align with the base of the camshaft caps.

[daveson]

True.

That dog don't hunt.

[bgcameron]

I did the disassembly today. Nothing appears to be out of the ordinary. All the splines are well-lubed, the U-joint feels good. The clutch housing nut seems tight, and it did not move under 100 ft-lbs of torque.

[daveson]

I'd mark the nut and shaft for reference, back it off the slightest amount possible (even less than 1/16 of a turn)  it might torque up further cause it takes more to start than to maintain when you get going. If the cover is still off.

[daveson]

Anyways was just about to post.

Straining an optic nerve further still.

That black plastic thingy between the steel backing of the chain guide and the tensioner; is that cracked? That's what it looks like to me. If so, could that increase the oil flow and reduce the oil pressure?

Apologies if this is yet another crap shoot.

[bgcameron]

When I had that apart I did not see any cracks. I'll recheck that nut torque tomorrow.

[daveson]

Ignore my clutch nut post for a mini, you don't want to back off the nut unless necessary. I just zoomed in on the tensioner. If that thingy is broken, it wants to be replaced, regardless.

Have a zoom at it.

[bgcameron]

I don't see what you're looking at. Could you do a screen shot and point it out? I had that tensioner strap out of the bike and I checked every bit of it and didn't see any cracks.

[daveson]

Dunno how to do that.

Zoom in where the tensioner contacts the backing of the chain guide. Looks like a bit of plastic to eliminate steel to steel contact.

I can't zoom when I press play, but in play mode the right half moves up and down. I'm more confident about it after I zoomed in.

[daveson]

This one is from a k100.

Did you check the black bit on the back?

[bgcameron]

I see what you mean now. I am 99% sure I checked that and didn't see any cracks. Isn't it more of a rubber than a plastic? Perhaps in the video it is squeezing and making it look like a crack?

Oh dear :( I really don't want to take that timing cover off again..

[daveson]

Mine's rigid plastic like.

It's easy access, especially compared to taking the output shaft out.

To me the video shows movement on the right hand side, like its come away from the guides backing, but that's with a small phone screen.

[bgcameron]

Mine's rigid plastic like.

It's easy access, especially compared to taking the output shaft out.

To me the video shows movement on the right hand side, like its come away from the guides backing, but that's with a small phone screen.

Perhaps I'll take a look during my next coolant change, which may happen soon because the water pump appears to be leaking from the weep hole. Speaking of leaks- it's leaking gas too.. not much, but there is some corrosion in the bottom left seam of the tank.

I'm tempted to send the bike out for a buoyancy test.

[Laitch]

I'm tempted to send the bike out for a buoyancy test.

[daveson]

This might also explain your zipper sound with abrupt revs from idle.

Maybe try the screwdriver sound test on the timing chain cover, about where the tensioner is, with sudden revs from a helper, and the other conditions.

If you gradually increase revs over 3,500 rpm, does the noise remain, or gradually reduce, or suddenly disappear?

Watchyagot.

[bgcameron]

This is the "zipper" sound I was referring to. My bike does this somewhat but it doesn't sound nearly as loud as the rattle I am getting. I've gone over the engine with a stethoscope and I wasn't able to find anything obvious. It's difficult to use the stethoscope while riding.

[daveson]

How's about the noise remaining or disappearing, gradually or suddenly, at some point after your noise at 3,500rpm?

I ask because if it disappears, that might be at a point where the oil pressure finally reaches a high enough point for the tensioner to work properly.

Watchyagot.

[The Mighty Gryphon]

God!  I'm loving this thread!

[bgcameron]

God!  I'm loving this thread!

Its turning into a bit of a Saga.

[daveson]

NFCKNBLVBL.