KZ750B1 Cam Chain Tension

When I checked the drive chain tension there didn't seem to be any point in the tire rotation that was tighter than any other. I mean I didn't feel the resistence to rotating the rear wheel change. Is this what I'm suppsoed to be looking for?

The drive chain MAY wear unevenly, creating spots in the chain where there is more slack than in others. If it doesn't appear to suffer from uneven wear, don't worry about it.

Not sure why your bike suffers this rattle on decel but does the 750 have a chain driven primary or is it gear driven? This is the hook up between the crankshaft and transmission. On a 650, this is done by a chain and there are constant complaints of this chain rattling on that model. The 900/1000 has a gear driven primary drive so it doesn't rattle from this position.

Once other rattle source is from your shift forks... if they are worn, they tend to rattle on decel. I have one of my carburetor test bikes where 2nd gear is out and the forks rattle terribly. I am rebuilding a spare engine right now and will swap it out and then swap out the transmission on the engine with no 2nd gear...

If adjusting the cam chain and the drive chain doesn't help, it could also be that the primary chain is stretched. If you use a long screwdriver as a stetoscope and hold it against the clutch cover on the right hand side of the engine, and then race the engine a few times, you should be able to hear it if the chain is making a noise. To be able to measure the freeplay you will have to take off the clutch cover though. I don't remember if there is any chain guides inside the clutch cover on the 750 like on the 400, but if there are, the chain guides are made out of rubber that will turn rock hard over the years, often causing a noise like you have got.

Btw, I rode a 750B this fall, and I'm pretty shure the engine always will make some "normal" clatter.