KZ900B Tuning Help

I just completed a replacement of the cam chain idler setup in my '76 900 LTD. Now I'm having trouble tuning the bike. The motor itself is stock with stock airbox and new filter (no silencer), all boots on airbox and intake are good. Exhaust is a Vance and Hines 4-1 gutted but with the endcap still in place, carbs are vm26's off a 79 LTD.
Carbs have been cleaned and literally everything in them is new, float levels are good, and they are mechanically synced. Currently running 17.5 pilots at 2.5 turns out, 107.5 mains.
I have gotten the bike to the point where it will idle at 1500 on the tach, and it sounds like that's about where it's idling. Won't idle any lower. I finally got to ride it last night a bit, and it seems low on power, kinda hesitant when throttle is applied. I avoided giving it any more than a quarter throttle, and kept it below 5 grand.
I'm wondering if these jets seem to be a bit small to anyone based on their experience, since the next step to me seems to be to swap out to 20 pilots and try and tune the idle down further. Also, are those 107.5 mains gonna be small? I have a few sizes larger that I can swap to, i believe 115, 120, and 122.5's. I'm in southern NJ, more or less at sea level to 500' above. Any advice?

If not already done, would (1) use a timing light to assure correct ignition timing and assure that the timing advancer is functional (not rusted and hanging in position), and (2) double-check the cam timing.

Good Fortune!

Oh, I see what you're saying. If the advancer mechanism was stuck open, I may have incorrectly timed the cams?

No. It is very unlikely that the ignition advancer stuck in an advanced position. Typically. It will rust in place while the engine is off. This will prevent the ignition timing from advancing as it should, possibly causing the symptoms you posted.
It is also possible that one of the cams could be retarded by one tooth, or that bith cams were set to the wrong timing mark, leading to the symptoms.
Two problems that cause similar symptoms.

Ok, well I can definitely say the cams aren't off. I checked and rechecked them multiple times when I put the engine back together last week. I haven't put my eyes on the advancer though. I will pull the ignition plate off tonight, check the advancer, and if it's good. I will check the timing with a light.

Looks like the 79's have 2.0 slides. (lean) The air screws are 1 1/8-1 1/4. Opening the screws makes them leaner still.
Steve

Hmm, my original correct carbs(which are ruined since the P.O. overtightened them and bent the carb bodies) had pilot air screws for low speed adjustment. These have the screws up front and underneath, so I figured they were adding fuel. SWest, you are saying I am adding air to the mixture when opening them? Or decreasing fuel?
Also, what does 2.0 slides mean?

If they're fuel you should be able to hear when you get best idle. One turn is 360* of movement. Try 1/18 and go out accordingly. It says turn them out clockwise from looking at them from the bottom. Stock is 1.5 cutaway. (rich) Others have 2.0 slide cutaways. (lean)
Steve

Wow, I wasn't even aware of that. Worst case I can swap out the slides from the old carbs hopefully. Man, this is making my head spin.

If you do that, switch over the emulsion tubes and needles too. I would take inventory of one carb first to see if all the matching parts are still there.
Steve

Yes, that's a good idea. I am going to pull the carbs again and swap everything to 76 specs. I'll check to make sure it's all there. The emulsion tubes are the brass tube that the needle slides through and the main jet threads into, correct? Do you think they were different from year to year? Could I verify that with a simple ID measurement of the tubes?

They are all marked. Who knows what the PO did.
Steve