First of all, I imagine you have all gone to adjust your chain, and after you set the adjusters, you tighten up the nut, and then the chain is suddenly too tight. You may also notice, that although you have the adjuster blocks lined up, the chain in riding on the edge of the rear sprocket (perhaps this is why chains are breaking?). Well, here is the reason. The adjuster block on the right hand side (nut side) is ridiculously loose on the axle. If you don't believe me, pull the nut off, and check it yourself. The right adjuster id is the same as the left adjuster, which is fine for the left side of the axle (where the axle is thickest) but on the right side of the axle, where the threads are, has a skinnier od. No matter how hard you try, when you tighten the nut up, the axle isn't going to stay in place. The solution? Intuitive Racing Products sells a chain block adjuster machined for the correct id to match the axle. Available through Lockhart Phillips. No, I don't sell their crap or have anything to do with it, they just make a good product that is definately needed on Busa's and any other GSXR.
On clunking. My Busa clunked no matter how tight or loose the chain was. I know that there is a common thought of running you chain super tight. Whatever tension you decide to run on that chain, check the slack with the rear suspension as compressed as possible (to simulate your weight and going over a good bump). If you don't have slack at this point, your chain is too tight, and you will eventually end up replacing your tranny output shaft bearings. If you ride 2 up (have some friends over for beers...) have someone steady the bike, you and passenger on bike, and someone to verify slack. Anyway, I'm getting off topic. The clunk....I went to put some new sprockets on my bike, and when I pulled the sprocket carrier off (first time rear wheel ever off the bike) I found that when Suzuki originally put the thing together, they folder over 2 of the cush drive rubbers, and smashed it all together. I righted the badly disfigured bits (new ones are coming) and the clunk is gone. I replaced the sprockets at the same time this happened, but I can't see how my aftermarket (afam) sprockets had anything to do with it. I did change 2 variables, but I can only assume the clunk came from the errant cush drive rubbers. If you have a clunk, check those rubbers out.
On clunking. My Busa clunked no matter how tight or loose the chain was. I know that there is a common thought of running you chain super tight. Whatever tension you decide to run on that chain, check the slack with the rear suspension as compressed as possible (to simulate your weight and going over a good bump). If you don't have slack at this point, your chain is too tight, and you will eventually end up replacing your tranny output shaft bearings. If you ride 2 up (have some friends over for beers...) have someone steady the bike, you and passenger on bike, and someone to verify slack. Anyway, I'm getting off topic. The clunk....I went to put some new sprockets on my bike, and when I pulled the sprocket carrier off (first time rear wheel ever off the bike) I found that when Suzuki originally put the thing together, they folder over 2 of the cush drive rubbers, and smashed it all together. I righted the badly disfigured bits (new ones are coming) and the clunk is gone. I replaced the sprockets at the same time this happened, but I can't see how my aftermarket (afam) sprockets had anything to do with it. I did change 2 variables, but I can only assume the clunk came from the errant cush drive rubbers. If you have a clunk, check those rubbers out.