My Dad and I just installed a 9" Delkevic slip-on  BUT, after it was installed my bike started acting funny. Whenever the engine gets over 6k the RPM's jump but there is a loss of power. I have not rejetted my carbs, I think that's what it is but, it's worrying me. 

Stock intake?

If the engine rpm "jumps" and there is a loss of power, you should be looking at the clutch. If your engine flattens out at higher rpm (loss of power but also struggles to accelerate), your jetting is lean.

Stock everything except exhaust. So, should I check the clutch? And if so, what do I need to check on it?

Perform the full cable adjustment as described in the website and/or in the forum. Since the engine produces negligible torque I find it unlikely a bike ridden sanely would wear out all those discs. It's more likely a correct adjustment will fix your problem. You didn't put low viscosity car oil in the sump, did you? If yes, try bike oil. If not, adjust the cable, both ends.

So... If someone WERE dumb enough to put some low viscosity 10W30 in their bike (such as myself  ) how could I fix it?

If the clutch didn't slip afterwards there is nothing to fix. On a big bike the fuel economy oriented car oils with their visco additives can cause slipping. On our bike I have to wonder. If it now slips, try replacing the oil with bike oil (no economy star symbol) or my fav, 15W-40 diesel oil (Rotella T). It's bike rated and compatible with wet clutches.

Again though if your clutch isn't slipping you cannot fix a slipping clutch issue.

Is it slipping?

IOW your Rpm jumps but the bike doesn't, right? Drain the oil and use something NOT energy conserving, plus check the cable anyway.

It slips a gear or into a false neutral every so often. Is that clutch slippage?

Clutch slippage is when the revs climb but the bike does not accelerate. It can be oil, clutch cable, or clutch related. False neutrals are when there is apparently an N between any gears other than 1 or 2. It can be oil, technique, or gearbox related.

If all the fun started after the oil change, suspect that first. The cable adjustment is routine maintenance anyway so check that too. As to technique, use calculated movements; an iron foot in a velvet boot. Shift with emphasis but without jumping up and down like you're on a trampoline.

Alright, I'll start with the oil then go from there. Thanks so much for the advice! I'm still learning how to care for my bike but I'll be damned if I stop riding haha 

Ok have fun!

PS since you are troubleshooting, change only ONE thing at a time and check the results before trying the next thing. Methodical approach is best.

Quote from: Disposable_Optimist on October 23, 2015, 11:02:36 PM
It slips a gear or into a false neutral every so often. Is that clutch slippage?

This could be a transmission dog set wearing out and not locking into the gear. Possibly shift till you hear that second click on the trouble some gears. I tend to do that on the upper gears where I'll spend some time.
Cool.
Buddha.