Keihin Carburetor Installation for Yamaha Banshee

figure 1

figure 2

figure 3

NOTE: If at any time during the course of installation of your new carburetors you are not completely positive of the correct installation process we recommend you consult or take your machine to a competent technician.

1. Remove front plastics and fuel tank.

2. Remove stock carburetors, Unplug carburetor switches. Unplug TORS system and remove, then using electrical tape, tape plastic leads to existing wire harness.

3. If you will be installing a TWIST THROTTLE you must remove the stock right hand throttle grip. After the grip is removed take some 220 grit sand paper and sand all the paint off the handle bar (where old grip was). The handlebar must be completely free from any paint, dirt, etc. that could impede the workings of the new twist throttle.
NOTE: If you are using an aluminum handlebar make sure the bar surface is clean and smooth.

4. Trace the black and black/yellow wires that come out of the stock thumb throttle. Thrace the (2) wires to the plastic plug in with the main wire harness. Approximately 1” down from the plug-in on the main harness side, cut the (2) wires and splice them together. It is also recommended that you solder the spliced wires and wrap them with shrink tubing.

5. Install DR MASTER-FLOW INTAKE MANIFOLD SYSTEM (if applicable, follow instructions included with your Master-Flow). MASTER-FLOW is recommended but is not mandatory, its usage will enhance you carburetor’s performance and increase reliability of the usage of stock inlet manifolds. NOTE: If stock inlet manifolds are to be used, you must take a razor blade and remove the 1/16” wide & 1/16” high piece of rubber on the top of each manifold. This is done so the clamp can lay flat.

6. DR recommends using the stock Yamaha Banshee airbox. The stock airbox will give you more horsepower across the entire powerband and the best possible filter protection. To modify the airbox to work with you new carbs, read the following simple modifications.

7. Start with the original airbox to stock carburetor rubber boots. (See figure 1)

8. Cut boots with a razor blade or equivalent behind the smaller diameter molded flange. (See figure 2) After cutting, sand edges so they are smooth. Clean boots.

9. Install modified boot onto the bell of Keihin Carburetor (See figure 3). The boot will need to be stretched a bit, but with a little effort, they will go right on. DR recommends using their (4pc) clamp kit part no. DR-2222 to secure the carbs on both ends.

10. With an aluminum or copper punch, tap down the clutch arm on the left hand side of the engine. Tap the arm down until the adjustment pointer is approximately 1/32” from the centercase. This modification is made to increase the clearance between the clutch arm and the float bowl.

11. Install carburetors into the inlet manifolds (with boots installed on bell side of carbs). NOTE: LEFT SIDE carburetor has float bowl cap welded on the bottom of it.

12. Install airbox.
DR AIR BOX RECOMMENDATIONS: Use Pro Flow Flange, K&N Air Filter with Outerwear. Lid will be optional. Use in very wet conditions. Do not drill holes in box or lid.

13. Install throttle cable into thumb or twist throttle. (NOTE: When using 35mm PWK carburetors, DR recommends using only twist throttles because throw on thumb throttle may not allow slide open and close all the way.) Attach throttle cables to carburetors. NOTE: On 35mm PWK models make sure throttle spring collar is in place under throttle spring to hold cables in place.

14. Set carburetor sync. Setting carb sync requires that both carbs OPEN and CLOSE at EXACTLY the SAME TIME. You must also make sure the carburetor slides open all the way at full throttle and close all the way when throttle is shut. After the slides are adjusted, make sure the throttle cable has a minimum of 1/8” of freeplay on each end of the cable. After all settings are set, work the throttle quite a few times to ensure everything works smoothly.

15. Install fuel line onto carbs in the same fashion that it was on the stock carbs. You can use the stock fuel line if it is in good condition on the 34mm PJ carbs. The 35mm PWK carbs will require approximately 2” longer line on each side of the “T”. Install fuel tank. Make sure clamps or equivalent are used on all fuel line joints. Make sure there are absolutely no fuel leaks.

16. Check Air Screw adjustment. Standard setting is 1.0 turn out. Both carbs must always be set exactly the same. Air Screw settings should be ½ to 1 ½ turns out (turning the screws in restricts the air flow, richening the mixture, out leans the mixture).

17. Check Idle adjustment.
34mm PJ: Turn choke knob up to raise idle, down to lower. Both sides must be set the same
35mm PWK: Turn idle screws located on left side of both carbs under carb tops. Turn in to raise idle, out to lower.

18. Start machine, set idles. Install plastics and go ride machine. Ride easy at first, maker sure to check jetting.