whizzer poor low-end torque

Discussion in 'Whizzer Motorized Bicycles' started by wes, Jun 1, 2009.

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  1. wes

    wes Guest

    Maybe there's an answer somewhere here, but i can't find it so far.

    I have an NE5 engine, milled head, copper gasket, torque is proper, mushroom lifters adjusted per Quentons instructions, 22mm carb w isolator, iridium plug high flow exhaust but only the oldstyle flex pipe now. timing advanced one tooth on the build, and i checked. i replaced the junk original auto clutch with a manual. i weigh 170 and the bike is lighter than a stock whizzer as its on a vintage cruiser frame. It runs smooth, sounds great, but i can easily kill the engine going up hill if i don't pedal like mad. top speed on flats is about 42 with high octane. Have about 800 miles on it so far. A 2.5 horse flathead Tecumseh i have on another bike easily beats it up the hills. (plus about zero maintenance)

    With the mods i should be able to easily go over these hill, but as it has no gears or low end torque it can't do this and also is slow on the start and really have slip the clutch so as to keep the revs up. I've re-adjusted the carb mixture to the best spot so far. have 26 i could put on but the slide looks smaller. Advance timing? Don't really want to go faster, just WANT SOME POWER! waaa!

    Hopin Bill Green or Quenton could help a little.

    Last edited by a moderator: Jun 1, 2009

  2. bill green

    bill green Member

    Hi Wes Its probably A smaller stroke than your other motor . More low end ??????? Whats helped mine is to get rid of the low end elec. sag. NGK IRD. plug , Hotter coil , Better CDI box . after that its about timing , carb , and compression . On my salt flat bike Im well above 150 psi . It would be great if someone made A 80mm manual pulley . So if you have any questions on plug , coil or Ign. PM me...Bill
  3. Kep1a

    Kep1a Guest

    I have 2 whizzers and the 70mm clutch makes all the difference in the world for me. I have a 26" with a 70mm and a 24" with a 90mm clutch.

    The 70mm clutch is night and day better at lower speeds and climbing hills. The 90mm on the 24" is marginally OK at best with riders north of 200# but works just fine with lighter riders.

    I swapped the clutches and find the 26" to be virtually unrideable on any larger hills especially without an adequate run before them while using the 90mm. The 24" bike with a 70mm clutch was a rocket off the line but was noticeably slower on the top end than the 26" with the same 70mm clutch.

    IMHO the standard clutch to use for hilly country is the 70mm. Although heavy riders or heavy loads in mountainous country would do well with the 50mm.

    Lastly checking your float settings and checking that your idle and main jetting is correct is critical before you do any other changes. A good rule is that the mixture screw is 1 to 1.5 out. If so then your idle jet is likely correct or close if the float setting is correct. An engine operating with even slightly out of tolerance settings can have profound and devastating results in one or more operating ranges of your engine.

    I worked on a friends 26" whizzer with the 90mm clutch and I found that he had set the float at 23.5mm+ to help with the flooding caused by pressure due to heat from the engine and our climate on the fuel tank. This was causing pressure to build and ultimately flooding the fuel bowl. While a float setting of 23.5mm to 24mm did help the flooding it caused low power in the mid and top rpm ranges. Lets not forget that information about this float level change was never passed on when I got the bike for low power concerns (it never is).

    Symptoms were as follows;
    It seemed to me at first glance to be a little lean at top end so I went to adjust the needle clip down one or two more slots. However the e-clip on the needle was set at the bottom slot already. I set the clip in the middle and proceeded with carb removal to install a main jet one size larger. Incidentally both of my bikes ended up in the center after jetting was final.

    I found upon float bowl removal that the float was set too low in the bowl at 23.5mm+ the bowl is about 24.5 to 25mm deep and at 23.5mm it left little room for the float to drop and open the needle to replenish the fuel being used at speed. What this caused was not only the fuel level was low at idle but at speed it became even lower due to the inability of the fuel to fill the bowl quick enough to maintain the minimum required level. The float needle did not drop enough to allow for adequate fuel flow.

    I did not change jet size (as it was the #82 like both my bikes) but I set the float to the 22mm setting. The test drive showed that this made all the difference in the world. The clutch slipped more with the added power and acceleration was adequate. The top speed went up about 8 mph. When I returned and shut the engine off the fuel began to over flow from the float bowl began to pour out the overflow tube. Shutting off the fuel stopped it but so did the release of pressure in the tank by removing the filler cap. I put a small pin hole in the white valve inside the cap and the problem was solved. You can't fill it to the brim any more but that is a small trade off.

    My advice is that you make for sure all settings are correct and your fuel is not stale. Only then can you evaluate what performance issues you have and what might be causing them. Check the basics first the look for other more expensive fixes only after you are sure all setting and basics are good. Many folks find the 90mm clutch has adequate acceleration and incline climbing abilities. So I suspect you have other more basic issues.

    Some reminders are...

    1) Head gasket leak due to the head bolts being too long or the shoulder on the bolt being too long, causing bottoming before reaching full torque on the head gasket.

    2) Plug gap or contamination on the plug

    3) Too much slack in the throttle cable preventing full throttle

    4) Stale or low octane fuel

    5) Dragging or binding drive train parts (clutch, hubs or brakes)

    6) Plugged fuel filter

    7) Dirty air filter

    To name a few of the basics that come to mind.
  4. Clutch

    I have to say that when I went from the 90 to the 70 mm autoclutch my bikes low end performance improved a lot too. Still get plenty of top end with Quentons motor mods.
  5. wes

    wes Guest

    I have some work to do!

    Not ready to try to find a 70 clutch (if one is made), but thanks for the long and detailed info on the carb adjustments, that may be the answer. I'll get to work on it. After that, i'll look into ignition. Thanks a bunch!
  6. bill green

    bill green Member

    Hi Wes when you want to get Info on the ignition give me A yell......Bill
  7. Hal the Elder

    Hal the Elder Member

    I recently traded my RPM-wasting auto clutch for a "slipper" (both with 90mm pulleys), and I just love the high gear ratio with the manual!

    It's like taking off from a stop in high gear with a stick shift car...you have to slip the clutch a lot, then you dump it at about 10 mph and buck-buck-buck your way up the RPM scale until you're happily cruisin' at 25-30 mph along the country lanes!

    This was the most satisfying mod I've made in the 7 months since I've owned my new 2005 NE5. (Now with over 300 miles!)

    Last edited: Jun 3, 2009
  8. wes

    wes Guest

    still working on it

    readjusted the valves per Quentons specs, they were just slightly too tight. cleaned the carb and changed to the aluminum manifold that was sent with engine and of course the heat insulator/hogged out restrictor plate. also readjusted the clutch and it works so much better now and the belt is tight. i think a have the carb mixture set good now. I could play with jets, but have done this in the past and settled on the one best previously.
    Thinking do i have a high lift cam? i think one was installed on the one i got. Guess i would have to take it out to check. Also i do have a flex pipe on it maybe that effects the engine. the pipe ends just back of the bottom bracket. Hmm. Just LOVE the new belts i got in for the front manual clutch. Gates Powerated #6828 They're green and have no black rubber surface or teeth. Totally quiet and grip very good. Tryem you'll Likem. I'll never go back to auto now. now if i could just get some more power...w.
  9. wes

    wes Guest

    Ah yes! a late nite ride.. 130 in the morning. pedal away silently from the sleeping locals and open the compression release. Set the float to in between 20 and 22mm and i think the high speed fuel loss is a thing of the past. nothing noticeable on climbing hills as thats another part of the engine altogether i see now.
    Would like to mention that i notice the pivot bolt moving side to side as i pull in the clutch. Just a little, but it does. I can't rock it by hand, but i have read the post by Quenton on changing this to a more precision fit. Why can't it be done right from the factory? Oh well something more to tinker with. Guess thats why i like to ride this one more. ',} w.
  10. Kep1a

    Kep1a Guest

    Glad to hear most of your issues were easily resolved. Refinement past the point of proper operation is a very personal task. Once you are sure everything is working as designed you can start personalizing the operation to fit your specific needs and environment.

    There are endless opinions as to what works best but your needs and environment may require more careful consideration when deciding what direction you choose to go. Chasing in the wrong direction can be costly and frustrating. The most important issue IMHO is to be honest with yourself when determining what you are going to modify and what you expect from that modification.

    Keep in mind that all decisions will have consequences or sacrifices in other areas, even more so if you strive to achieve perfection in only one area. It is all about compromise and/or sacrifices for achievement of perfection in only one operational environment.
  11. Kep1a

    Kep1a Guest

    PS; Check this thread for your pivot bolt issue. I have the auto clutch but the slip clutch would benefit from similar improvements.


    Don't forget to lock tight the nut allowing you to leave the bolt the ability to pivot freely without coming loose.
  12. wes

    wes Guest

    fuel starvation??

    I want to thank all of you first off for all your help. I reset the main jet and adjusted the carb and settled on the 86 jet. It really turned out to be that i had some junk in the tank that was block the outlet enough that when i got to high rpms it would starve. also some of the power loss was from a head that wasn't quite flat in some areas. after some wet dry paper and glass plus some elbow grease the fit is great and noticeable power increase.

    Now i'm back to a burbling sound at the 40 mph range and it almost died once. its like no fuel again. i check the tank and outlet. no blocking. the float is set at 23mm or around 7/8 and this is the 22 carb. new filter. other wise it runs great, but this is frustrating. every once in awhile it coughs, but not predictable. i might contact Bill G. for the hotter ign. i also want to try setting the timing ahead, but had trouble popping the flywheel off for drill and tap. maybe you'all have run into this prob. include the bike pic. you notice i added a vent tube to the fuel cap to avoid vapor lock. w. should add that over 40 is downhill, or tailwind, plus high octane... wet i weigh 170. gotta love a whizzer.

    Attached Files:

    Last edited by a moderator: Jun 23, 2009
  13. bill green

    bill green Member

    Hi Wes I would check your tank vent next to make sure your not vapor locking at full throddle....Bill
  14. alberndt

    alberndt New Member

    Weak low end power and no carb adjustment

    Converted my auto clutch to a slip clutch, really like the way it runs, however now finding that I have weak low end torque and wants to bog down on hills. Tonight I rode about 15 miles and when got back to the garage it was idling fast/like too fast/tried to adjust the idle speed slower and there is no adjustment, keeps the same RPM.
    Any hints on the idle speed and on the torque/drilled out the restrictor plate but done nothing else. Appears when had the auto clutch on, was slipping the daylights out of the belt from the engine to the auto clutch as well as clutch slipping.

  15. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi alberndt,

    Check for leaks around the intake manifold. An easy way is to spray WD40 around the intake gaskets with the motor running. If you detect any changes in RPMs it means there is a leak.

    Have fun,
  16. Kep1a

    Kep1a Guest

    Mine has an idle of almost 2100 rpm when on the stand and the brake is off (wheel spinning).

    I pull in the brake or put it on the ground I get 1100 to 1150. So I'm thinking that may normal on your conversion to a slip clutch.

    You should be able to idle it down though. Check the throttle cable to be sure it is not so tight as to hold the slide in your carburetor up even when the idle screw is allowing it to go lower. That's all I can think of.
  17. RdKryton

    RdKryton Active Member

    That is what I was thinking also.
    Good luck.