'79 KZ400 here, wondering about a few weird sounds

Hi guys,

I have a '79 Kawasaki KZ400, been riding for a year now, the engine is a champ and haven't had much trouble with it. However, being new to bikes, there are two sounds that are giving me pause, and I'd like to know if they are normal or what I should start fixing.

Noise #1) My front disc brake makes a high pitch noise while at speeds above 50mph or a so. It's not constant or happens all the time, and if I gently squeeze the brake the noise will go away. I took off the caliper, the pads don't seem worn. The rotor has some grooves though, and I'm wondering if that's the culprit. Sounds like something's loose though. My grandpa said it's probably a pebble getting in there, but that seems too frequent to be so.

Noise #2) This is the one that worries me. When I put it in neutral and coast, even at slow speeds, I can hear this grinding sound coming from the transmission. Last summer I changed the oil and that helped it out a bit, but I get the feeling that's more fixing the symptom not the problem. I don't have the technical skill to rebuild a transmission, so how much of a time bomb is this one?

Thanks for all the advice! Here's a picture of my bike, along with my toolbox, figured the two will get to know each other pretty well.

1) pads are vibrating

2) do not put it in neutral and coast.

Nebr_Rex wrote: 1) pads are vibrating

2) do not put it in neutral and coast.

Hey, thanks for the reply. I looked up some things about vibrating pads, it seems the fix is just to replace pads and rotors, so I'll do that.

Regarding coasting in neutral, I normally don't do that when riding, except when I was trying to hear the noise better over the sound of the engine.

rosshettel wrote: ...When I put it in neutral and coast, even at slow speeds, I can hear this grinding sound coming from the transmission. Last summer I changed the oil and that helped it out a bit, but I get the feeling that's more fixing the symptom not the problem. I don't have the technical skill to rebuild a transmission, so how much of a time bomb is this one?....

Might result from an old worn out kinked drive chain.
Could try lubing and adjusting the chain. And inspect it for kinks.

Good Fortune!

Patton wrote: Might result from an old worn out kinked drive chain.
Could try lubing and adjusting the chain. And inspect it for kinks.

Good Fortune!

Ah hey, thanks! I think that might be it. My chain is pretty loose, and I tried tightening it up a few days ago, it helped somewhat. It might be too worn out and time for a replacement.

Be sure to follow the instructions in the manual for adjusting the chain. Too tight is just as bad or worse than too loose. It needs a specific amount of slack. Ed