knocking noise at RPM above 3000.

[DiverRay]

That's a good thought Bonz, However I did adjust the cam chain tensioner, Thanks

IF it's the factory unit, I would NOT trust it! Go with the ACCT upgrade! I have had the factory one "back off" when running hard, so I no longer trust them. Just my $0.02, but there are a LOT of the bikes now running with the Venturer adjusters here.

[Bonz]

Ranger, I was addressing the OP with that question... but it does apply to you as well. Glad you are still interested in the thread which he seems to have lost interest!

In any case, what DiverRay said is where I was going with the question. The ACCT mod is a great way to ensure it isn't the cam chain because of a known ineffective stock tensioner.

I did it on my 80SG and 80G, easy peasey and should be a must-do mod.

[XS1100_OEM4ME]

Knock

Back on the "knock" thing. I have found three things in the OEM design to be wrong. I know, with OEM 4 ME call sign, WTF.
First, the fuse box, everyone knows it is junk and should be replaced before trying to figure out why your bike runs poorly, start there, its cheap, easy and will fix a lot of crap.
Next the electronic ignition and octy. Both great ideas ahead of there time. Here is the problem, the vacuum hookup. You need to balance all the cylinders vacuum into one constant flow and then reduce that flow the same way you do on your carb vacuum gauge's so the octy and ignition advance don't jump around like crazy and ware out the octy diaphragm and the advance wire leads.
All an easy fix. But the 3000rpm "knock" noise is most likely the advance jumping around and causing that rattle and jumping in the motor sound / pull. If it smooth's out when you increase the throttle and decrease the vacuum, well the explains it. Yamaha did a tech. paper back in the day.