Engine knocking/grinding

Hey guys!

Just had the trip of a lifetime! 4200 miles on my 77 kz650C from New York City to Napa California. Went west through Michigan and through the upper peninsula --- straight through North Dakota ---- through Montana and up to Canada --- the state of Washington and south through California!. Amazing time. Took 8 days and am already ready for my next trip!

However, I have some trouble coming from the bottom end. At about 3000 miles I started hearing a knocking coming from the transmission through 1st and 2nd gears, Didn't really know what to think... tightened up the chain and did some maintenance like an oil change and all... but...
At about 3500 starting hearing a terrible metal on metal grinding at about 30mph. It doesn't increase or decrease with revs and remains pretty constant... but goes away coming down at lower speeds.

I have read many things and am wondering what you guys think. I don't think it is the primary chain but am thinking more of a ball bearing somewhere down in there. Any tips/suggestions on where to start? Also, what kind of work am I getting myself into? Don't mind doing the work but I don't have a garage around here.

Thanks guys!!

Did you check the cam chain tension?? only fishing here as from your description it sounds more chronic, the other thing is the clutch basket. I'm only mention things to check before you rip the motor out, without more detail I can only guess.

I just completed a similar trip on my '80 750. About 1800 miles into the trip the motor started making a distinct rhythmic grinding sound. i stopped and took off the clutch adjusting cover and also the alternator cover to see if I could find anything amiss such as a bearing coming apart. All was tight and dry and after a minor cam chain adjustment which made no change i decided it would either be OK or it wouldn't. Almost 3000 miles later all is still well and I have learned it is noise made by the drive chain going over the counter shaft sprocket with the high spots rubbing on the chain guide. I'm still running 630 chain and in spite of lubing it faithfully it has gotten stiff and doesn't run over the sprocket smoothly. I'm now awaiting 530 chain and sprockets to install a conversion. You can do a better job of isolating the noise than I did by running the motor, stationary, out of gear, and taking the drive chain out of the equation. Hope your problem turns out to be as simple as mine is.
Regards,
Art

Were there any metal bits in the oil or filter when you changed it?

You mentioned that you "tightened up the chain." How much slack did you leave in it? Ed

I was hearing some noise from the cam chain and tightened that up early on in the trip so its not that.

I need to check for metal bits ... going to do an oil change soon.

The chain i tightened up on 2 occasions. Once leaving a little too much slack still and this time with a little bit of play. It was rubbing a little and slapping but no loner. I took the cover off and checked around the counter shaft sprocket but will try that again today. It does feel like it is coming from that side. I have run it in neutral on the center stand and switched gears and the noise isn't as apparent as it was when on the road.

This guys post is dead on. Wish he would have followed up!
www.kzrider.com/forum/2-engine/68260-new...bike-new-noise#68260

When you do the oil change is when you can open up the clutch cover and have a look inside.......could be as simple as a basket bolt come loose in there or more. You can take off all the clutch plates to check them too (without needing a garage) and check for warpage etc.
Have you had that cover off before? Hopefully the gasket is reusable but it might be prudent to get a new one. Just throwing it out there....noise coming from the motor for sure?

Thinking maybe the wheel bearing?

That's easy to test. Get out on a lonely road, bring the bike up to enough speed so it's making the noise; click the tranny into neutral, and shut off the engine. The bike will drift along happily with no noise attributable to anything attached to the crankshaft. If you still hear the noise it's coming from the wheels, the drive chain/sprockets, or part of the tranny/clutch. When doing this test if the noise is still present I would pull in the clutch to see if the noise changes.

If the noise goes away when the bike is drifting with the engine off you probably need to open the engine up to see what's going on inside. Ed

Noise stays. A steady slow grinding. Already took a look at the chain and adjusted it so that cleared up some issues....So it most likely has to be the wheel bearings right?

It could be wheel bearings. Can you tell if the noise is coming from the front or rear axle area? If so, you may be able to raise that wheel off the ground and spin it to see if the noise can be positively isolated. If it's the rear you probably should remove the chain from the sprocket when you spin it. Ed

I will check that out later. Thanks!

It could still be a number of things. So it makes noise at speed even with the engine off and in neutral? You can rule out the engine. But it could still be the wheel bearings, chain and sprocket, gearbox seal or the gearbox output shaft bearing. All these parts still move when in neutral at speed.