Tools you will need:
Small Flathead Screwdriver
Phillips Head Screwdriver
4mm Allen wrench (some applications)
Needlenose Pliers
10mm Wrench
All H.P. Carb kits use the same carb (Walboro WA-167A), except for the "Pro-Mod" carb kit available from Pacific Sand & Water Sports. These carb kits are usually sold as carb kit only or with filter and velocity stacks. The kits available do have one big difference from each other and that is the intake manifold. There are 3 different manifolds available (1) The Zenoah Manifold (2) Billet Manifold (ECC) (3) Pacific Sand & Water Sports Manifold.
1- Walboro WA 167A Carb 1- Intake Manifold
1- H.P. Carb Gasket (black) 1- H.P. Carb Linkage
1- Return Spring & 1- M6 Nut If you purchased a complete kit you should also have : 1- Air filter & 1- Velocity Stack
Ready for Installation:
Step 1: Remove the air filter lid, take out the two filter elements and the flame arrestor (silver plate). Remove the 2 phillips head screws inside the air box. Remove the air box, and carb from the intake manifold.
Step 2: Now that the carb is loose, remove the throttle cable from the carb. And use a pair of needle nose pliers to pull off the fuel lines.
Step 3: Remove the 2 phillips head screws from the stock intake manifold and remove the manifold. The gasket between the intake manifold and cylinder is re-useable unless it is torn, it usually sticks to the cylinder when the intake manifold is removed.
Step 4: Before you go any further, Assemble the carb, velocity stack and manifold. Check to see that the screws don't come through the backside of the manifold. This problem is very common with the brown zenoah manifold and will cause kill switch to have problems, and a severe intake leak making tuning the carb impossible.
Step 5: If you are installing the brown Zenoah manifold you will need to trim the cylinder shroud to clear the upper right hand corner of the intake manifold, or the manifold will not seal properly causing an intake leak.
Step 6: If you are installing the PSWS "Hi-Tech" manifold or the ECC manifold, install them with the pulse hole down and the slot to the right hand side
Step 7: Now remove the throttle cable end from the stock carb by removing the "C" clip, and install it on the throttle arm of the H.P. Carb.
Step 8: Next install the throttle cable and nut onto the H.P. Carb Linkage.
Step 9: Now slip the return spring over the end of the throttle cable and fit the end of the throttle cable into the cable end. You will need to hold the carb throttle arm open to get the cable in. Pictured above is the proper return spring installation
Step 10: Install the yellow fuel line onto the barbed fitting nearest the primer bulb and the blue line on the other barbed fitting.
Step 11: Next slip the carb mount screws through the velocity stack and install the velocity stack on the carb. With the screws all of the way through the carb slip on the H.P. carb gasket
Step 12: Install the carb onto the manifold with the primer bulb towards the gas tank. (up on Zenoah manifold)
Step 13: With the brown zenoah manifold the throttle cable must come up from under the deck and make a "u-turn" This can cause poor throttle return if the throttle cable is not in excellent condition.
Step 14: PSWS recommends that you spray the moving parts on the carb with WD-40 for better operation
Step 15: If you are using an ECC or Billet intake manifold , disconnect the kill switch at the bullet connector below the carb, or you will have No Spark.
Step 16: Now install the air filter and you are ready to prime and tune your H.P. Carb.
Tools you will need:
Before you begin:
Before we can tune we must get the terms straight. Here are the terms and descriptions to keep us on the same wave length:
Mixture: Mixture refers to how much of each.
Rich: Rich means alot or in this case more than perfect.
Lean: Lean means little or less than perfect.
Bog: This is the sound you hear due to a lean mixture. When you open the throttle by squeezing the trigger to the bars, you are letting the engine draw in all of the air it can. If there is not enough fuel added to that air, the engine will not accelerate, it will bog and usually die.
Chutter: This is the sound an engine makes when it is getting alot of fuel. You may hear this sound at any throttle position including at wide open. Go-PedsŪ run better with a little "Chutter" at low to mid throttle settings.
Tuning the H.P. Carb
The H.P. Carb includes 3 adjustment screws. These are the idle adjustment screw, low throttle adjustment screw & high throttle adjustment screw. Some people call them the Low speed & High speed screws, but they actually operate based on throttle opening not engine speed. Idle Screw: The idle screw keeps the throttle slightly open allowing enough air to pass for the engine to idle. Turning this screw in or clockwise allows more air to pass. Turing it out or counter-clockwise decreases airflow.
Clockwise = more air = faster idle.
Counter-Clockwise = less air = slower idle. Low Throttle Screw: This screw adjusts the amount of fuel added to the air passing through the carb at partial throttle, or up to 1/3 throttle openings.
High Throttle Screw: This "T" Screw adjusts the amount of fuel added to the air passing through the carb from 1/3 throttle to full open. NOTE: The fuel added by the Low Throttle Screw is still being added at 1/3 to full open. Adding more fuel with the Low Throttle Screw will affect the High Throttle mixture slightly
In order to begin tuning your carb you must first get the engine started so you can listen for Rich or Lean mixture. We recommend these initial settings to start with:
Idle Screw - All the way clockwise
Step 1: If you just installed your H.P. Carb Kit. Push the primer until fuel can be seen returning to the tank in yellow return line. (Primer Note: The primer brings fuel from the tank to the carb. Priming the carb not the engine. Raw fuel is not actually being pumped into the engine. Pumping will not help start a cold engine).
Step 2: If the engine is being started for the 1st time with an H.P. Carb, we recommend you pull off the filter and place your finger over the carb opening so no air can pass. Now pull the pull start. After each pull check to see if your finger is wet with fuel. Once your finger is wet, the engine is ready to fire. Hold the throttle 1/2 to wide open* and pull start. Once the engine starts keep it running at the lowest possible RPM. (* without holding your finger on the carb)
Step 3: Warm the engine up all the way. When you are sure it is warm let off the throttle to see if it will idle. If the engine idles slow, chutters & dies then turn the Low Throttle adjuster in 1/4 turn and try again until it idles steady.
Step 4: Once the engine idles steady, use the low throttle screw to get a slow chuttering idle. If the engine slowly chutters and dies, then it is to rich and the low throttle screw must be turned in, to lean the mixture a bit (1/8 to 1/4 turn). If the idle speed gets too fast with the leaner low throttle setting use the Idle screw to get a slower idle speed. The ideal low setting is as rich as possible without loading up (Chuttering & Dying). Once the low throttle mixture and idle speed are set, you are now ready to move on to the High Throttle Adjustment.
Step 5: The object of High Speed adjustment is to obtain the highest possible RPM under load with the richest possible setting. The richer you can keep the mixture while still getting peek RPM the better. The engine will accelerate, it will live longer, run cooler and respond better. Just adjusting the high throttle screw for max RPM on the kick stand would leave the engine very lean and when the engine is under load it probably won't accelerate well at all and could seize.
Instead, start rich and lean the mixture out in small increments (1/8 of a turn). Testing each new setting under a load. Once the acceleration starts to suffer, you have gone to far. (Go back 1/8 of a turn). It is better to depend on cylinder porting to get peak RPM than on ultra lean mixture settings. Optimum settings for typical stock engines is about 1 1/8 to 1 3/4 turns out.
Carb Symptoms
Problem: Engine Chutters at full throttle and doesn't rev high.
Problem: Engine bogs from low speed.
Problem: Engine idles but slowly dies.
Problem: Engine idles smooth but runs poor under load unless throttle is full open.
Problem: Engine idles fast and stalls when you try to slow idle speed down.
Small Flathead Screwdriver
Phillips Head Screwdriver
(example): How much sugar added to your coffee. How much oil added to your gas. In this case how much fuel being added to the air passing through the carb. This is the fuel / air mixture.
(example): If your coffee is too sweet, it is to rich with sugar. If your engine is running rich, it is getting to much fuel added in with the air that the engine is bringing it.
"The mixture is rich".
(example): If your coffee is not sweet enough then it is to lean, there isn't enough sugar. If the engine is running lean, there is not enough fuel being added to the air the engine is bringing in.
" The mixture is lean".
Low Screw - 1 1/4 turns out (counter-clockwise from closed)
High "T" Screw - 2 turns out (counter-clockwise from closed)
Solution: The "T" screw is to far open. Close 1/8 turn and test under load until acceleration suffers and then open 1/8 turn. NOTE: Engines with stock porting tend to chutter at high RPM.
Solution: The "T" Screw is to far closed. Open it 2 or more turns and tune for chutter. NOTE: Worn parts, tall gear ratio with heavy porting, high intake duration, restricted exhaust and low cylinder compression can cause low speed bog.
Solution: The low speed screw is to far open. Turn in 1/8 turn at a time until idle cleans up. If idle speed is to fast after adjustment slow the idle down using the idle screw.
Solution: The low speed screw is to far in. Turn idle screw all the way clockwise and set a low idle using the low throttle screw.
Solution: These are the symptoms of an intake leak. Go-PedsŪ usually leak at the manifold to cylinder gasket. Make sure the carb mount screws arent' going to far through the manifold and causing an air leak. Screw marks or cuts in the gasket are a tell-tell sign of screw interference. You can check for leaks with the ped running. Spray WD-40 around the manifold, if the idle speed changes you have a leak.
95+ Angle Plug Engines G23LH Engines Go-Quads
Tools you will need:
Phillips Head Screwdriver
Side Cutters
3mm Allen Wrench
8mm Allen Wrench
12mm Allen Wrench
Flywheel Puller
Oil Filter Wrench or Channel Locks Red Locktite
Business Card
Step 1: Remove the 5 phillips head screws attaching the fan cover and remove the fan cover with pullstart still attached
Step 2: Remove the spark plug wire from the plug. Disconnect the kill switch wire from the throttle cable below the carburetor.
Step 3: Remove the Black phillips screw holding the engine shroud on, it is above the fender, between the gas tank and motor, and remove the shroud.
Step 4: Remove the spark plug, and the two 3mm Allen screws holding the ignition coil to the cylinder
Step 5: Remove the Air Filter Lid, both filter elements, the silver flame arrestor, and the two phillips head screws which attach the carb to the manifold. DO NOT LOSE THE GASKET between the carb and manifold. Swing the carb out of the way with the fuel lines and throttle cable still attached.
Step 6: With the piston at top dead center mark the flywheel and the cases with a sharpie marker so that the marks allign at Top Dead Center. Double check to make sure they allign at Top Dead Center
Step 7: Now put a second mark 8mm to the right (clockwise) of the first mark. Measuring 8mm can be done with an 8mm wrench if calipers are not available. More space is NOT better! Adding more than 8mm will increase heat, and can cause internal damage.
Step 8: Now remove the 12mm nut in the center of the flywheel. DO NOT USE a Screwdriver to hold the flywheel. An oil filter wrench will not damage the flywheel and is cheap at any auto parts store. You may also use large channel locks
Step 9: Using a flywheel puller; remove the flywheel. If you do not have a puller DO NOT try to remove the flywheel! You will damage the flywheel, crank, cases, etc...
Step 10: With the flywheel removed, use side cutters to remove the key from the crank.
Step 11: Now with the flywheel off, bring the piston to Top Dead Center. Re-Install the flywheel so that the mark on the flywheel is lined up with the second mark you made on the cases. (The one on the right). Hand tighten the flywheel and check to make sure the 2nd mark is lined up with the flywheel while the piston is at top dead center. Now tighten the flywheel to 20ft/lbs and recheck your marks a final time.
Step 12: Using a business card between the coil and flywheel magnets to set the clearance, re-install the coil. Rotate the flywheel a full turn to make sure there is no contact.
Step 13: Before re-installing the spark plug, we recommend cutting the seal off with side cutters. This will raise the compression and increase torque! To ensure a good seal we use Red lock-tite where the washer was removed, NOT ON THE THREADS!
Step 14: Re-Install the shroud, routing the kill switch wire so that it does not contact the hot cylinder.
Step 15: Re-Install the fan cover, kill switch wire & the plug wire. You are now ready to ride.