Jet kits for 99 CBR600F4 what size should I use

Richard, I would suggest you go with a stage 3 jet kit for improved air flow. Ebay has them for a great deal. I'll post a link. Good luck. ^^
Dynojet Stage 3 Jet Kit For Suzuki GS650 GS 650 1981 1982

Buy a haynes or clymer manual soon

When too much fuel is being supplied to the carburetors the engine is flooded. When you remove the spark plugs it allows the fuel to dissipate enough to allow the engine to run again. Drilling out the jets is not an accurate/preferred method for changing the jet size. Most of the time the jets end up being drilled too big. You can save money by just buying main jets. A jet kit usually will come with the slide needles made with a different taper from the stock needles. You may need to break down and buy a jet kit or a least replace the main jets with accurately sized main jets (not drilled out jets). In other words your main jets are just too big.

You can try driving the bike after the install. After you change the exhaust it will run lean. You may want to coat the inside of the mufflers with an anti blu-ing agent or your headers will discolor. If when test driving you notice the bike has developed a flat spot in the acceleration curve you will want to re-jet the carburetors. The easiest way is to buy a jet kit from Cobra, Dyna-jet,etc.($80-$100). Other wise you can just buy several sets of larger jets and change them out till you are happy with the way it runs. Most people that change the mufflers and put in a jet kit, also install a K&N air filter .
More air flow + fuel flow = more exhaust flow (more power)

its likley to be running a bit to week,, try opening up the fule mix screw just a bit to let in more fule

I believe the standard starting place is to go 2 jet sizes bigger, but I would check with the manufacturer of the big bore kit to make sure. Hope this helps

general rule of thumb is to go up about 10 jet sizes,unfortunately it is a bit of trial and error,and you may have to swap out diferrent sizes to get the bike running right,(jets are quite cheap though)but first step about 10 sizes from standard,your local dealer should be able to tell you what jets are in it and supply replacements,if you change to a hgh flow aftermarket air filter you may have to change jet sizes again as changing the filter may effect the mixture ratio in the carbs,,hope this helps

• First I would go get stock plugs from the dealer. Plugs with incorrect heat range can cause overheating.
• Drain the oil and replace the oil filter. Refill the crankcase with fresh oil. Also be sure exhaust gasses are getting through the exhaust pipes okay
• Check the spark timing. and clean or replace the air filter.

Your mechanic probably installed carb rebuild kits in each carb. This is good but the correct main jets may not have come in the generic kits he bought. Too small a main jet can cause overheating. Pull the float bowl of whichever carb is easiest to get to. Remove the main jet and look to see what size it is. There will be a number i.e. 3.0 stamped on the jet. Call your dealers parts department and ask what size main jet is stock. The smaller the number, the smaller the jet. Re-jet the carbs if needed.

I hope you can rate this solution as a "FixYa". Thanks!