Whizzer Carb jetting

Discussion in 'Whizzer Motorized Bicycles' started by Kep1a, Jan 28, 2009.

  1. Kep1a

    Kep1a Guest

    I am still jetting my bike and thought... Man I wish there was a list of ball park starting points for a given range jet size for a given range of elevation.

    Let me start by saying that my personal goal would be in the order stated to, ensure reliability, economy and release the least bad emissions on the environment that I can.

    A quick google search can give you the elevation answer...
    We are relatively low in elevation (2548' at the airport). Around Tucson, desert scrub is replaced by desert grassland at about 3500' and oak woodland replaces desert grassland at about 4000' elevation.

    It is true that any modifications will affect your final settings. My intent here is to establish a starting range not a final jet setting as that will vary quite a bit based on humidity, temperature, exact or range of elevation for your given area. I settled on something not too lean for break in but not so rich that it would contaminate the oil and have performance issues.

    While I am not done fine tuning my jetting I believe that I can safely say that...

    #82 with the needle "C" clip in the center at my 2500' to 2780' elevation in a dry climate is a good starting point. This setting does lend itself to stalling with a cold engine, but that is something I would expect with the current choke design.

    So @-2780' = #82 centered C clip seems to be a good starting point for my area and range of elevation.

    Does anyone have a list they can post? Can we create a list here if there is not a list available?


  2. RdKryton

    RdKryton Active Member

    I don't have a list but my 22mm carb has a #86 jet with the clip set in the second notch. (from the top) I am at 480 feet above sea level.

  3. Baverian

    Baverian Member

  4. WZ507

    WZ507 Member

  5. bill green

    bill green Member

    howdy I set up all my 22mm at #86 main jet and needle at one notch from the lowest needle setting . or second groove down from the top... hope this helps..Bill
  6. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

  7. Kep1a

    Kep1a Guest

    Great links and information everyone.

    I was however more looking for or wanting to create a down and dirty resource to get folks quickly in the ball park for their specific elevation.

    I'm not only looking to get a record for new and old Whizzer owners to reference but knowing what range should be working would reveal a carb problem on your new ride like I had with a #30 idle jet where only a #92 or larger main jet would let me idle with the mixture screw fully closed. Once I got the #35 idle jet I began dropping jet sizes until I got to #82 with a centered e-clip and idle mixture screw at 1.5 turns out. I developed a head gasket leak so I'm replacing the thin metal gasket with the new copper one that Whizzer now uses. But as a result of the gasket change I as of yet have not finished my jetting.

    While the idle jet was unmarked an elevation to jet size chart would have shown that my Idle circuit was very lean. I am also finding that while the Main jet in theory should only affect the top 3/4 throttle and top end, the main jet has proven to change not only the mid-range but also the idle significantly. I'm reasonably sure that the slide design and cut is the reason for this. While not a problem it is good to know that the main jet will have and effect on the entire throttle range.

    A down and dirty chart will also be helpful for those of us who move around the country and would like to avoid the entire what jet do I start with guessing game. With a GPS and 20 minutes work you can have a good running Whizzer at home in Miami Fla. or camping in the Oregon area, that is if you knew a ballpark jet size to start with. I plan to bring my Whizzer with me when I take an RV trip so a reference of this type would be very helpful.

  8. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Kep1a,

    Although I applaud your efforts, in order for you plan to work correctly, you must have a stable base. If all Whizzer motors were equal it would be possible to make a chart to aid in the jetting process. The differences between motors will make the chart incorrect in most cases. Many things effect the main jet size, including the muffler insert [3 different factory versions, and at least 2 aftermarket options], and in some cases no muffler insert. Another major difference in jetting is the head [at least 3 different factory versions on the NE, and the NE-r is another version]. Add the camshaft [at least 2 versions from the factory], and type of lifters [again at least 2 versions from the vendor]. I have also detected casting extrusions on some cylinders, and not on others in the exhaust port area, which effect jetting. Was the head milled and or the combustion chamber cleaned up, does the motor use the earlier steel [.010"] or later copper gasket [.020"], if so it can effect the final outcome of jetting.
    The reason I mention these facts is research has taught me many things about "dialing" in the carburetor. When the 22 MM carburetor was shipped on the earlier NE production motors often it had a larger main jet [anywhere from #90 to #95] but after milling the head [mostly to flatten the surface, and create more gasket sealing area], re-working the combustion chamber, and installing a copper head gasket the jetting suddenly became very close to correct. In later production NE motors with the #88 main jet, hi flow muffler insert, mushroom lifters, and the longer intake manifold, the jetting was still on the rich side, but much closer than earlier models. Because of the demand I purchased hundreds of main jet for stock, but 95% end up using a #82, #84 [mine are actually a #85] main jet. Depending on the motor a few have used the #86, but isn't common for most areas.

    The most common mistake made by owners is wanting to use larger jets [a common mistake thinking big is always better]. While it is true most companies install main jets larger that needed to be on the safe side [much safer to be a little rich as too lean], if carried too far the extra fuel can wash some of the oil off the cylinder [not a good idea].
    Usually a large main jet will cause the motor to "bogg" above 3/4 throttle, and many think it is running out of fuel, and opt for a larger main jet which produced the same results or worse. There are 2 easy ways to "dial" in the carburetor, first look at the spark plug, and secondly keep a close check on the exhaust pipe as it leaves the manifold. In order to use the plug as a guide, you must ride the bike in the range you want to check, an example would be 1/4 to 1/2 throttle for a long time would tell if the needle jet is in the right spot. If you wanted to check the main jet, WOT for about 2 miles, kill the motor, check the plug. The mention of the exhaust pipe turning "blue" is a serious problem and means the motor is running way too lean, STOP and correct jetting right away, do not continue to ride!

    Hope this information is helpful, and is not intended to "bash", or discredit any company, person, or vendors.

    Have fun,
  9. uncle_punk13

    uncle_punk13 Guest

    :) I'm still fighting all the variables and such... LOL!!!
  10. Kep1a

    Kep1a Guest

    Yes Quenton I see your point. I still think that with enough input by owners one could get reasonably close if everyone denotes their elevation and mods.

  11. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Kep1a,

    Here is my information at sea level on a stock motor with the restrictor intact, camshaft advance one tooth, re-worked Whizzer mushroom lifters, aluminum intake manifold, #82 main jet, and the needle dropped one notch.

    Motor with milled head [.065"], reworked combustion chamber, copper head gasket, hi flow muffler insert, aluminum intake manifold, EZ Motorbike mushroom lifters, intake lifter set at .006", and the exhaust lifter .008", valve seats re-cut, valves lapped in and liquid tested......#85 main jet with needle in the center.

    Motor with Westman head, hi flow muffler insert, Westman copper head gasket, valve seats re-cut, valves lapped in and liquid tested, EZ Motorbike mushroom lifters, P.C. Hi lift camshaft [.202 lift], .009" intake & exhaust lifter settings.........#80 main jet and needle down one notch.

    Motor with EZ Motorbike Hi fin head, 26 MM carburetor, decked cylinder, re-cut valve seats, no muffler insert, Hi lift camshaft, .005" intake lifter clearance, .007" exhaust lifter clearance, custom copper head gasket [.010"], camshaft advanced one tooth, K & N air cleaner, Irid. spark plug......
    130 main jet, needle up one notch.

    Motor with CRYS. head, re-worked mushroom lifters, hi flow muffler insert, decked cylinder, custom copper head gasket, 8 MM headbolts replacing the 10 MM bolts, re-cut valve seats, intake lifter set at .006", exhaust lifter clearance .008", stock NE camshaft [early]advanced one tooth, lapped valves & liquid tested, 102 main jet, needle down one notch.

    Have fun,
    Last edited: Jan 30, 2009
  12. Kep1a

    Kep1a Guest

    Quenton you most assuradly have earned the Carb jetting merit badge.

  13. Anybody have a part number for the #86 main jet?