Sounds like rod knock , but not....

So I picked up a kz100 that's been sitting for awhile. (sound familiar so far) Cleaned the carbs , checked cylinder compression, changed oil, put in new battery, fired it up. First thing I notice is a sound like a rod knocking. Listen closer, , maybe not. Pull in the clutch and it goes away. Good sign I think? Any ideas what I should be looking for when I pull it apart? Is it something that will jump out at me or something less obvious like worn springs? It's coming apart anyways but any ideas are appreciated. Thanks.

BTW, I took it for a test ride down the street. It shifts fine and rides fine with no slipping either. It just sounds horrible at idle.

Is it idling too slow? If so, it could be gear backlash. Run the idle up a little.

is this noise just at idle ,when u pull in the cltch, or while riding as well when u pull in the clutch?
i have seen the clutch basket spings go,1st hand. mine did not make any noise. i just happened to find a piece of spring in the oil pan when i did a rebuild.
I can see how it could make a noise like a rod though.
As the springs wear they can push the metal around them outwards.Or the springs themselves.if it goes out enough it could rub on the blocks suport ridges as they pass.
u cant see this without spliting the cases.
You might be want to check for metal in the oil pan and behind the clutch cover. Just as a precausion.

Mine had some broken clutch discs, one was cracked and another had a peice missing, it made a terrible racket but would change sound when the clutch was disengaged.

Hey lx460...

If you havnt already, check the camchain tensioner. The Pilot mixture screws. Manometer vacuum sync the carbs (or have it done for you).

The one thing that has happened to me, on more than one occasion that sounds kinda like a knock, is the stupid starter clutch bolts. Twice I've had to dissasemble the starter clutch and torque/threadlock the clutch assembly bolts. (They're down good now!)

Trust me , when those bolts are backing out it makes the engine sound HORRIBLE at idle, bet then as soon as you cruise along (over 2500rpm) seems to dissapear.
I "think" your clutch may be dragging slightly, causing a drop in rpm with it out. Mine did this after sitting for a LONG TIME... Adjust at the cover, accordingly.

Once all that stuff is done proerly, these engines start to sound pretty good. You can just search the forum for "how-to" info for the above mentioned.

Cheers!, and good luck...

...patience!

sync your carbs,adjust timing chain and tune it up if you havent already

Clutch noise at idle is normal; the friction plates have tabs on them that engage with matching slots on the clutch basket. The plates have relative motion against the clutch basket which creates noise.

If the clutch plates/basket is worn, the noise gets worse. Barnett clutch kits, the type that have thin plates, tend to gouge out the basket and create lots of noise.

Other possible problems include broken basket springs and as others have mentioned, broken plates and such (quite rare).

Best to pull down the clutch and have a look see. Look closely at the basket for any notching.

Good luck.

i have the same thing going on. havent figured it out yet.

that is a normal noise guys!!

if the engine is out of tune it is louder

you can synchronize and idle drop all 4 carbs then turn the idle up a bit but that is normal.

holding in the clutch quiets the lash from the crank to basket

it is the straight cut gear lash. straight gears make noise and do not side load. unlike the GS 1000 gs1100 they have a side cut gear that is very quiet but creates side thrust in hi-performance engines.

well mine is a little more and seems to go away when warm.
i have two other kz's and what im hearing ain't acceptable as normal

they tend to do it more when cold then should go away as the motor warms and smoothes it self out.