I have a 99 GSXR 600 that has been jetted. When starting off in 1st gear tho, you have to get the RPM's up to about 4 grand or it just lugs. I've actually ended up killing it a few times. I think it needs to be re-jetted?? It has a full Yosh Titanium Headers and Exhaust on it.
The Yosh full system is tuned for high end. You will always have a low range lug until you get into the higher RPM range. If it's not real bad then stay where your at.
You want to learn and do it yourself?
Iíll add my copper pieces on doing your own jet work. DONĒT DO IT! Unless you really feel, you will need to do it often. Different jets for track days, altitude for different tracks and such. If youíre a street rider SAVE THE TIME AND HAVE A DYNO SHOP DO IT!
Screw the shop I want to do it you say.
Ok.. then before you even start get your valves adjusted, get some new plugs, have the carbs synched, get a new air filter and whatever else you need to have your bike in 100% running condition before you re-jet. You may find you had a valve out or a flat spot that caused the power sag. A jetting will only make it worse. Buy a jet kit from someone, it'll have multiple jet sizes and good instructions. Get your tools and service manual. Read about your carbs in the manual and what you can find on web searches because thatís all the info youíre going to find on these things. Iíve looked and itís a Mikuni BDSR OEM part carb. Minkui has not a lick of info on it to offer us. There are a few web pages Iíve come across but didnít book mark them
myself many times for that as Iíve yet to re-find the page. Get the mikuni tuning manual and quick jet card if your going to be doing altitudde changes. The book is a great tool to understanding Carburetion technology.
For special tools your going to need an impact screwdriver, venire calipers to measure float levels made for carbs, their 40 bucks from factory Pro or Kowa tools. Long Phillips screwdriver. T-handle allen keys. You need decent tools to do this so make sure have them first. Youíll also need a good place to work on them. The kitchen counters donít work so well as your going to have some gas in them to drain and then theyíll stink up the house real quick. Not to mention gas fumes inside can be very dangerous to you and the house. Do it outside somewhere if you don't have a garage.
Youíll find out that every part of the carb will have to be bought separately and through a Suzuki dealer should you need to replace parts. OEM parts baby.. Be careful with all the parts and pieces. The shits expensive to replace. They do not sell a rebuild kit for these. You have to buy what you need. Get the carb diagram with all the part numbers as your going to need it. Ron Ayers has it on their website in the microfiche section.
Re-jetting our carbs are a real bitch. They are very sensitive to change. They prefer a lean mixture and seem to choke when you richen them up.
It's a fine science I'm finding and has been a thorn in my side since day one. It'll take you 6 hours the first time you take the carbs off the bike, jet and then put it all back in to go for the first of many test rides. I can do it all in 60 minutes now. Needle clip adjustments are done on the bike and take 15 mins when you get good at it. Always take the tank off; itís easier to work on then having to worm your way under and around the tank prop thingy. You donít have to remove the rear plastic like the manual says. You can pull the tank out by pushing the plastic slightly.
Get a few cans of carb cleaner spray and clean those carbs off REAAALLLLL good once you get them out before you remove a single screw. Use the cheap brand to get the outside crap off and the good stuff for the inside. There is a difference in carb cleaners, the cheap stuff canít burn when sprayed into a running engine whereas the more expensive good stuff can, read the can and youíll see. The good stuff breaks down gunk better also.
You'll need the impact screwdriver to remove the screws on the float bowl cover. Donít try and use a regular screwdriver, youíll strip the head and then your really fucked. Replace them with allen socket bolts, avail at your local fastner store. Bring the screw with you to match up. It's a metric bolt size. Get 20 of them as you'll need some for the neelde covers later. Clean the inside really good with the good stuff once you got them open also. Notice how brown the float bowll area is.. That's residue and varnish. Clean it up good. While the tank is off, clean and check the fuel pump area and screen as itís in the same condition as your float bowls.
Main and Pilot jets increase in size increments of 2.5. MOST gixxers have #1-4 at 125.5 and #2-3 at 122 main jets. SOME have only #1 bigger than #2-4. CHECK yours when you take them out. All 4 use the same size pilot, stock is 12.5
Donít tighten the main or pilot needles to tight or youíll bust em off in the carb. They only need .6 lbs of torque. I did it once and got very lucky with a paper clip to get it out.
Check your fuel float level height and adjust if it's required from your jet kit instructions. If not then make sure they are set to what the manual states. Float height is reverse of what it looks like, to raise you lower the clip, to lower you raise the clip. It doesnít take much to bend the clip so do it in small increments and be as accurate as you can. All 4 floats need to be EXACTLY the same height. Take your time and do it right.
Make sure you adjust or reset the air screws. You may have to drill the caps to access them. Follow the service manual if you do. Donít put new caps back in until you got your final adjustment done and you donít have to make anymore any time soon.
Needle clip height adjustments.
DON'T LOSE THE TINY VACUUM SEAL O-RING UNDER THE BLACK COVER!! If your doing needles w/carbs on the bike, put a rag on the head and under the carb bodies to catch them should they fall off. Should you lose them, most shops have to order em for you and it's $2.50 a piece for them. Get 4 new ones anywho, good to replace them. Watch them carefully when you put the cover back on, they can be buggers to stay in place sometimes. I like to lick them and stick them in their place. It works.
Pull the slide out of the carb and clean it with cleaner. Clean the slide area in the carb also.
Youíll need a pair of needle nose pliers to get the needle retainer out of the slide. Pull it slowly and smoothly. Watch out for the small spring inside, donít lose it. Remember how it all came out. Matching tapers is where you start for clip height if your kit doesn't say where to put it. Hold them next to each other and youíll see the tapers, place the snap clip in the matching groove. Press down on the needle very carefully to set the clip, use the flat part of the pliers and your thumbnails to push down on it. Donít bend the needle or you have to get a new one. You'll change your needle height a few times to get it just right so remember what your doing. Put it back into the slide and put the retainer back in. Press it until the o-ring seals. It has a groove it sets in; you donít need to jam it in. You should be able to twist it with the pliers easily.
Slide it back into the carb body. Be careful that the diaphragm seal sits in its groove fully so you donít pinch it putting the cover on. If it just wonít set right and the rubber is all flimsy, then you need new diaphragms. $13 bucks a piece and the dealer has to order themÖ Once the cover is on and in place push the slide in all the way into the cap to make sure itís not pinched or binding on the inside cover. Itíll make a nice slow swoosh on the way back if everythingís in place right, tighten the screws and go to the next one.
Once all 4 carbs are done with jets and needles, put the carbs back in making sure the intake ports are nice and clean before doing so. Get the choke cable in first and then the throttle cables. Then set the carbs in place and make sure they are seated in the ports correctly. Tighten them. Re-set the throttle cable and return adjustments for any slack, tolerance is in the manual. Make sure all electrical connectors are together, vacuum hoses are attached, air box hoses on before putting the tank back on. Make sure you route the tank vent lines in their proper path. Hook up the fuel pump vacuum line, fuel line making sure the filter is still in the line and then the power lead. Make sure you didnít leave any rags in there, drop the tank after you know itís all together and start her up. Itíll take a few cranks to get the fuel pump to fill the bowls.
Immediately youíll notice a difference in the exhaust tone. Let her warm up and then go for a test ride. Follow your jetting instructions test ride section on how to check if you got it right.
Need more info then check out http://www.factorypro.com/tech/carbt...m_engines.html
Something not right other than clip height, then welcome to hellÖ go to the top and start over..
Got it first shot then pat your self on the back and laugh at us who have to do it repeatedly finding the right combo.
Once you get your final settings. get your carbs synched again. They go out a little when you handle them alot.
I ended up using 132.5 mains on 1-4. 130 mains on 2-3.
12.5 stock Pilot. Oddly the holes are bigger on stock OEM 12.5 than Mikuni stock 12.5 pilots. Tried 15, 17.5 and 20 pilots and the 12.5 worked best
Air screws 2.5 turns out.
Stock float height
2nd clip in needle
I still have a mild lean burp when it goes from pilot to main at 8k rpm. Everything else is tits on.
Itís going to the shop to be dyno tuned for 135 main jets in 2 weeks. Iím sick of pulling my carbs out and going on test rides. I haven't had a real good ride in 3 weeks now.
I warned you in the beginning to go to a shop.
I didnít and here I am. Knowing enough to write this novel and change jets and shit in less than an hour. Listened to all the ppl who told me to not fuck w/600 carbs knowing now that what they said was right.
Donít do itÖ Let someone else deal with it unless you want to punish yourself.
I can't wait for the revamped 04's to come out. fuck this carb stuff. I want FI now.