Pilot Screw Setting

[dannymax]

It doesn't matter what was done to the mufflers, if you have OEM headers, which it sounds like you do, then it is still going to act like a stock system. The headers are the restricting part of the system, anything done downstream of them will have very little, if any, impact.

Try returning to an OEM set-up, jets-#152.5, #90, #170, oem needles and springs.....remove airbox tape, etc. and see what that does for you.

 

[D-Max2012]

Try returning to an OEM set-up, jets-#152.5, #90, #170, oem needles and springs.....remove airbox tape, etc. and see what that does for you.

Tried so far.
OEM specs as per 91 service manual:
Jets for carbs 1 and 3 = Mukuni 152.5.
Jets for carbs 2 and 4 = Mukuni 150.
Mukuni #90 and Munkini #170 on the others.
A/F screws out 3 1/8 turn out. (not in manual.. says preset - Riding and adjusting)
I plan to pick up some stock needles to try them.
Springs look like stock but I have nothing else to compare them with, to know for sure.
Plugs all new and gapped to specs.
Had to repair a faulty Pulse Pickup unit. ( it would cut off after it warmed up).
Replaced cracked Carb boots.
Set all float levels to 17mm
Synched up carbs
Cleaned carbs 3 times - Final time was with an Ultra-Sonic cleaner – U-S Cleaner removed stuff that never came off with previous 2 cleanings. Had MASSIVE amounts of crud in my tank after a fill-up. This HAD to have come from the pump. Tank is physically too small to have 1/2 cup of this nonmetallic crap that clogged filter and left me stranded on the road. Tried multiple times to rid the tank of this.. Finally had to order a spare tank off E-Bay. Fully coated with KBS tank sealer. Fliter and carbs crystal clean now.
Note: in the beginning of trying to diagnose this issue, I did find that the old carb diaphragms had small splits in them, so I changed out to new diaphragms. The newer material is a bit stiffer than the old ones. The old ones flopped around in your hand. The new ones hold their shape. I'm wondering if the added stiffness of the new diaphragms is not allowing as easier movement of the slides, as the old one would have.

 

[tugla]

What needle do you have now,what were the jets the carb came with