Rejet your
SV650
for $10
and get the same performance
as an $80 jet kit!
This rejet scheme was tested by a fellow SV650 owner named Jack Roe against the Factory brand jet kit. He discovered that over the counter pilots, mains and a couple .020 shims (3mm washers) will produce the identical dyno result. I think it took 17 dyno runs to get it right and prove to himself that over the counter parts worked just as well.
Carburetor removal requires 60% patience and 40% skill. First follow the steps in how to shim SV650 carb needles up to loosening the carburetor clamps and lifting up on the assembly. After the clamps have been loosened and the carbs are free to wiggle the next step is removing all other pieces that connect to the carbs.
First locate and disconnect the electrical connector by pressing on the release tab and pulling apart as seen in the first photo. Disconnect the throttle cables as shown in the second figure. Disconnect the fuel line as shown in the third photo. The throttle cables can be difficult to remove from the throttle wheel at this point but can be done most easily by tilting the carbs to the side, exposing the throttle wheel to unhinge the cables more easily. Disconnect the idle speed adjustment by snapping it out of the clip as shown in figure 3. Pay attention to how it is routed.
The choke cable is most easily removed from the handle bar and snake it back through. The choke/dimmer/horn assembly comes appart with 2 screws and the cable is easily removed from the choke lever. Bill Metz (all around good guy and fellow SV owner) recommended this and I found it to be the simplest way. At this point you have already discovered the carbs are free from the bike. Be warned a lot of gas can leak out of those little carbs so be ready. Cover the intake tubes with a clean rag or foil to keep dirt from entering the engine.
Now that the carbs are removed place them on a clean work surface like a work bench or a patio table like I did. Keep your work area clean as dirt, metal shavings or other debris must not be introduced into the carb.
Remove the 3 float bowl screws by using an impact driver or a grip enhanser. If you are too cheap to spend $25.00 for an impact driver from Sears then spend $5 and buy Craftsman GripDoctor at Sears. This stuff works as good as they say. Just put a drop on each screw (figure 4), use a number 2 screwdriver and apply steady increasing pressure and the screw will break free. You will have to put some potatoes behind it, but it will break free.
After the float bowl is removed (figure 6) the jets can be replaced. Replace the main jet by unscrewing. Hold the nut below steady as you unscrew the jet as seen in figure 7. Insert the new jet and tighten up snug but do not overtighten! (figure 8 & 9) The pilot should be replaced next. Unscrew the stock pilot and replace it with the 17.5 pilot as seen in figure 10 & 11. Tighten up the pilot snug but do not overtighten! Replace the float bowl and retighten screws nice and tight. Some people use an anti-seizing compound on the screws to make it easier for future jetting changes.
Repeat the steps for the other carb. If any dirt or debris gets into the float area use your handy dandy can of carb and choke cleaner to flush out any debris before reassembly.
Some people have said they had to adjust their float height. I did not have to do this procedure and the jet kit instructions I saw said to "make even to leanest float". To me this means don't mess with it unless you have to. If you feel you need to know more about this subject the Factory Pro web site has info availible about float height.
Shimming the needles need to be done next. It is important to install 2 .020" (3mm washers are .020") shims under each clip. Detailed instructions with video can be found HERE.
After the carbs are back together and the needles shimmed the idle mixture screws must be set. The air/fuel screw is covered with a brass plug due to EPA regulations. Instructions on removal can be found HERE. Jet kit instructions recommend starting with 2 turns and increasing by 1/2 turn increments. I found that 2-1/2 turns seems to be about right.
I recommend drilling the air/fuel plugs after rejetting because of the large amount of brass shavings produced by the procedure. Try to keep the carbs clean by covering both ends with aluminum foil and clean brass shavings after the procedure. You are ready to reinstall the carbs.
Be patient and make sure you reconnect everything and double check everything for tightness (tighten the carbs to the manifold and then try to pull up on them, if they come lose then they aren't tight enough), check all vacuum hoses are reconnected and choke cable is reattached. You really don't want an air leak between the manifold and carb. Stop salivating. You are almost ready to ride.
Consider performing what some call a snorkelectomy on your air cleaner. Removing the air snorkel will help unleash the most power and performance from the bike. The procedure is a bit time consuming but worth the time and effort. Instructions can be found HERE. For that last 0.6 HP you could Drill Your Slide Holes.
Now that you have rejetted, set the air/fuel screws and performed a snorkelectomy you are ready to go. The grin on your face will days to wipe off as you have unleashed the beast buried deep inside the motor. Wheelies are all too easy, power comes from idle to rev limiter. You will dream of chasing down Duc 748's... Its a natural reaction.
Main Jets: 137.5-140 (for stock exhaust)
140-145 (with aftermarket exhaust)
Needle: 2 shims under clip (U can buy here)
Air/fuel screws: 2-3 turns (2.5 seems good for most)
Float: make even to leanest float. (if you even check it)
Jack Roe's multiple dyno runs showed an aftermarket full exhaust and stock filter worked best with: 140 mains, 17,5 pilot, 2-1/2 turns and 2 shims. Read the whole article HERE.
My current setup: desnorkled, full race exhaust 152.5 mains, 17.5 pilot, 2-1/2 turns, 2 shims, and a drilled slide hole.
Another good setup is desnorkeled, full exhaust 152.5 mains, 17.5 pilot, 2 1/2 turns, 2 shims.
Your setup could be different depending on type of exhaust, air filter, altitude and other mods. Trust your butt but stay close to the recomendations you see here.
Home Page
How To Shim Carb Needles Page
How to adjust Air/Fuel settings
How to Perform a Snorkelectomy
How to Drill the Slide Holes
resources
updated 11/19/06
