1985 GPZ 750 Carb Dilemna

Well, I finally got back into picking up another bike to work on and have ended up with carb fun land. The stock carbs on the GPZ 750 were installed with K&N Filters and Vance and Hince exhaust. I've rebuilt the carbs, cleaned every knock and cranny, got them running good at idle and throttle under no load. Now heres the kicker (9 bikes, never had this one), the bike once under load acts like someone is using a dropper to feed it gas. It just has no power and when I choke it, it gets the power back. Knowing this, obviously running extremely lean, but with the pilot screws 4 turns out, 125 mains, not too sure where to go next. Any insight will be greatly appreciated, as I can now break down carbs in under 30 mins now...

Put the stock airbox back on

Believe me, if that was an option, I would. I've even looked for one on ebay, but no dice. Personally not a big fan of pods...

Anyone? :blink:

If not already done, would assure o'rings on pilot adjuster screws are in good condition.

Also, would use strobe-type timing light to assure ignition timing is correct and is rapidly advancing and retarding when rpm is varied by blipping the throttle.

Good Fortune!

Would also assure fuel level is within specs by performing the clear tube test on each carb.

Good Fortune!