Slapping or Grinding noise when let off throttle

I have a slapping or grinding noise when I let off of the throttle. It makes me think its the primary chain. I dont think its the cam chain or the balancer chain, because it only does it when its in gear and riding. it doesnt do it when the bike is sitting there idleing or being revved up. Can anyone else confirm this theory or give me anymore ideas to look at. The bike is a 1980 kz440. Thanks a lot

vosberdv1975 wrote: I have a slapping or grinding noise when I let off of the throttle. It makes me think its the primary chain. I dont think its the cam chain or the balancer chain, because it only does it when its in gear and riding. it doesnt do it when the bike is sitting there idleing or being revved up. Can anyone else confirm this theory or give me anymore ideas to look at. The bike is a 1980 kz440. Thanks a lot

If not already done, would assure final drive chain is in good condition, well lubed, and free of any kinks. And that rear sprocket also remains serviceable.

And also check and assure that the front (counter-shaft) sprocket is in decent condition and hasn't come loose on the spline.

Good Fortune!

2x what Patton said. I would suspect the main chain assy.

I've replaced the final drive chain with an O-ring chain. I will take the sprocket cover back off and make sure everything is still good down there. Thanks for the input

Look for metal shavings! :blink:

Would also double-check drive chain alignment between sprockets.

Okay to eye-ball, sight down the chain as it leaves top of rear sprocket and connects to front sprocket.

Chain should be straight as an arrow. As the sprockets should align perfectly with one another in the same geometric plane.

When adjusting the chain, don't rely on the "marks" provided on both sides of the swingarm, as the marks are sometimes misleading or simply inaccurate.

Good Fortune!

I believe the 80 440 doesnt have a primary chain... crank gear drive if I remember correct.

The 440 has a primary chain on the right hand side of the engine. They are known for being noisy, but its generally at low RPM, and when under acceleration. The guides are plastic and you can inspect the primary chain by draining the oil and pulling the right engine cover off.