top speed

Discussion in 'Whizzer Motorized Bicycles' started by ren, Mar 3, 2008.

  1. ren

    ren Guest

    I had the cast 90mm auto clutch on my 2007 Whizzer NE5, 160 miles on it, and didn't like the "off the line" tork at all but the top speed was good, 35 mph. By the way I weigh 175 lbs. I put the aluminum 50mm clutch on it and the low speed tork is great but the top speed went down to 24 mph at a screaming 4000+ rpm, I knew it would.
    My question is can I hog out the restictor plate and go to a one size larger jet and improve my top speed, or is that not possible with the current gearing "50mm". Thanks for any help.

  2. RdKryton

    RdKryton Active Member

    You can open up the restrictor plate and that will help a lot for power but may not give you much more speed. Don't remove it just open it up. It is needed to help keep heat from boiling the gas in the carb. I don't think you need to change the jet but I may be wrong here. You may find that the improved power will work well with the 90mm auto clutch too. That way you get your speed back without over revving the motor. Also these engines are not really broken in till you get about 500 miles on them so don't scream it yet.
    Good luck and have fun
  3. JemmaUK

    JemmaUK Guest

    I dont know much about the whizzer engines but modifying the tune and carb settings before doing something to the drive train is better then adjusting something which sounds like its more likely to tear your engine up then help anything..

    It *should* be possible to adjust the mixture settings and the like on the engine to give you more pick up - it may even be that as the engine runs in it will get stronger in the slow to middle range.

    With mine, which is a 32cc GEBE kit on a fairly heavy Schwinn cruiser I can get 30mph flat out which is more than enough. If I want more then just add a tuned pipe - the drivetrain is the last thing you should be looking at until tuning and adjustment to the engine and friction reduction is sorted out..

    When I had my old bike in the shop and had them clean it down to fit a front brake it came back to me like a new machine, completely different, simply because all the old crud encrusted lubricants had been cleaned out.. I think just that gave me maybe 1 to 2 mph better flat out just because of the reduction of rolling resistance against such a small engine (25.4cc zenoah)

    There is also the advice that GEBE gives that it is best to ride up to a few miles an hour before cutting in the engine (if that is possible on a Whizzer, I am not sure) which means the engine doesnt have to labour at low revs and instead gets into its torque/power band alot quicker - it also helps the clutch life..

    hope that helped

    Jemma xx
  4. Clutch, speed, and Carb.

    Hi Ren, my brother put a 50mm on his personal bike, and after riding it, I would not recommend increasing the speed much with that clutch.

    It seems that the 70mm back end, with the restrictor port-matched (if legal in your area), will improve your performance.

    I would not rejet, unless the engine tells you that is what it needs (plug read).

    You do not mention the mileage on your engine, remember that these engines tend to increase in power untill about 500 miles on the speedo.

    Try these things?

  5. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Ren,
    Maybe you should have selected the clutch in the middle. There are 3 sizes, 50MM, 70MM, & 90MM. Here are the numbers if using a 26" Whizzer, at 4000 RPMs the 50MM =19.336 MPH, the 70MM =27.06 MPH, and the 90MM =34MPH. At 5000 RPMs the 50MM =24.17034MPH, the 70MM =33.8MPH, and the 90MM =43MPH. Of course you can add power to the motor, raise the clutch ratio to 6.97 X 1 [2001 Whizzer automatic clutch] turn up the throttle until the motor hits 6130 RPMs and figure out how to stop a Whizzer at 68 MPH. Just kidding! However most modified Whizzer NE motors will easily run out of numbers on the speedometer [5750 RPMs = 50 MPH], and leave the stop signs with ease, even accelerate up most hills.
  6. ren

    ren Guest

    Thanks for everyones help. Maybe I'll enlarge the restictor plate to match the intake, leave the jet alone until a plug check and try a 70mm clutch. The bike is a 24" model with 160 miles on. What I'm looking for is good "off the line tork" for pulling out in traffic and 30 to 35 mph crusing speed without winding the motor so tight. May have to go back to the 90mm clutch for my crusing speed according to Quentons numbers. More expermenting, man I love this motorbike!
  7. JemmaUK

    JemmaUK Guest

    I know this sounds stupid but why not up-wheel it to 26 inches?

    that assumes they'll fit - that'll give you a little extra speed and mean you wont have to rev the thing within an inch of its life..

    I also seem to remember that there are some tuners out there that can do wonders with whizzer engines although by all accounts they arent cheap...

    Glad you are enjoying your machine - I'm in love with mine too - every time I am out on it I get a smile a mile wide - unless its tipping it down which is another matter entirely...

    The tradeoff will always be top end speed against torque - that even happens with exotic machinery such as bentleys (I get a headache every time that guy shows off when I am walking down the street, but I digress) the more you tune for top end the more intractable and difficult/slow the rest of the rev band will be.

    Jemma xx
  8. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Ren,
    The difference between 24" and 26" is major! My wife's bike is a 24" and my 1999 is a 26". The same motor on the dyno was 6 MPH faster on the top end. On the 24" the motor turned 62 MPH and the 26" did 68 MPH. Here are the revised numbers using a 24" Whizzer. 4000 RPMs with the 50MM clutch= 17.848MPH, with the 70MM=24.98529 MPH, the 90 MM=32.12394 MPH. 5000 RPMs with the 50MM=22.31108 MPH, 70MM=31.23161 MPH, and the 90MM=40.15492 MPH. The NE motor has a lot of "hidden" power that can be extracted with a little effort and a small amount of cash. The best way to pull the power from the NE motor is to "match" the intake port parts, and use a good muffler insert [approx. $20.00]. Another way to find even more power is to mill the head .070" and use a copper head gasket. If you make these changes the motor will easily pull the 90 MM clutch, and cruise at approx. 45 MPH. I can assure you it will leave a stop sign rather quickly.
    Whizzer OuterBanks,
    Last edited: Mar 4, 2008
  9. ren

    ren Guest

    I chose the 24" model becasue I'm 5' 9" tall and it fits me better. The bike is a 2007 model with the stock muffler insert, I think it's a 1" hole. Is there a better one? I'm a little leary about doing something like having the head milled at this stage, although in the future I would like to make some serious upgrades to the engine. Any info on that would be nice. For now I'm going mild. So Quenton, if I open up the restrictor my low end tork will be better?, and put the 90mm back on to get my crusing speed back would be the way to go?
    Thanks to all again
  10. RdKryton

    RdKryton Active Member

    In a word Yes
    Opening the restrictor to match the intake on the cylinder will increase your torque dramatically. You will be able to use the 90mm clutch so you get your top speed back. If your muffler insert has the larger opening, approx 1 inch, you may already have a hi-flow insert. This is a good thing. Quenton is a master with these engines. He has taught me sooo much about Whizzers that I feel comfortable answering your questions. I'm sure he will correct me if I am wrong. These things are so cool.:):) I can't wait for the warm weather to get here in the northeast.
    Enjoy your ride.
    Last edited: Mar 5, 2008
  11. ren

    ren Guest

    Thanks RdKryton, looks like I'll open up the restrictor and put the 90mm clutch on and see what happens. I've been lurking around here for awhile and have read about some of the engine upgrades that are avalible. I would like to do some of them, if not all of them! at some point after the engine is good and broke in. Any info on types of upgrades and pricing would be great.
    Thanks again
  12. bill green

    bill green Member

    Hi ren I would increase your compression as Quintion mentioned .070 will work very nice the new new ne5 baffle is a more open flow system (not like the old ones) And then run the 90mm ..Hope this help Bill Green Vancouver Whizzer
  13. ren

    ren Guest

    Top speed update

    Just wanted to update everyone that helped me with getting more torque from my NE5. You folks are great. I opened up the restrictor and put the 90mm auto clutch back on. Am amazed at the addition torque it makes, and I got my top speed back. I live in a small town of about 9000 pop. and am the only owner of a Whizzer that is ridden. Iv'e been told there is a guy with an original one, don't know what year or model, but haven't ben able to verify that. So I'm on my own for learning about these wonderful machines. That's where you guys come in, thanks so much. Also I'm going to buy a modified head form Quenton when they become avalible and install that. Can't wait!
    Thanks again everyone.
  14. RdKryton

    RdKryton Active Member

    I'm glad you got the results you were looking for. When I first arrived here on these boards, I knew very little about Whizzers. Quenton, MotorbikeMike, and Bill Green have taught me a lot about Whizzers. These guys are great and will always answer your questions. The search feature here works very well and you may find your answers without even asking the question. That's a cool thing. Have fun and think warm.


    P.S. Thanks for posting your results.