motor rebuild instructions [Whizzer]

Discussion in 'Whizzer Motorized Bicycles' started by Mennis, Jan 17, 2010.

  1. Mennis

    Mennis New Member

    I have a 99 whizzer that is slowly falling apart. After riding for at least 20 minutes it starts to loose power and the engine bogs down. I would like to go through the entire bike top to bottom including a rebuild of the engine and all other parts. It has 1600 miles on it. Is there an instruction manual that would help me do this?
    I would like to do it myself as a project. I was thinking of taking a local small engine class also.

  2. professor

    professor Active Member

    If oil has been keep in the engine and there are no mouse nests in the fan shroud (making it overheat) look at the fuel system, I doubt there is anything major wrong, since it does run good initially.
  3. spunout

    spunout Member

    that, and the fact it has only 1600miles. thats not much at all.
  4. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Mennis,

    High possibility the valve seats are loose.

    The fix is to purchase a new cylinder upgrade kit.

    I personally spent thousands of dollars trying to fix the original WC-1 cylinder. I even purchased special tools made to "peen" the seats into the cylinder. I had tapered seats made, screw in seats made, oversize seats made, purchased special bonding liquids from Loctite #640 & #620], etc, etc. I wasn't the only one spending money on trying to find a solution, there were several others that also failed to make it work.

    The problem has to do with the grade of aluminum and the high operating tempature of the motor. The Aluminum expands much quicker than the valve seats, and once loose the seat loses its seal. Often the motor will run [after it cools down], however when the motor heats up it will bog and die. Many times I sat on my Whizzer waiting for it to cool down enough to ride it home.

    BTW, Everyone one was sure they could fix it, I heard how they were the world's greatest or knew someone that was the best. I watched a lot of money and time spent on the problem, and never heard of a solution. However if you want to try I have a bunch of the WC-1 cylinders sitting on the shelf in my parts room.

    I won't bore you with the details, but you might want to find the NE cylinder upgrade parts ASAP [they are becoming more difficult to locate].

    Have fun,
  5. Rebuild

    Yeah buy a new cylinder & then fix another problem that most dealers will be happy to sell / help you with too... It's so much fun fixing a broken down Whizzer!! I suggest the class on engine repair before you go too deep.....
  6. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Mennis,

    You are welcome to call me @ 252-475-0406 [cell]
    If you need more information.

    I can make a copy of the service manual, but it doesn't give any information on the rebuild process.

    If you want to learn & play around I will gladly donate a WC-1 cylinder, all you need to do is cover the shipping cost

    Have fun,
    Last edited: Jan 18, 2010
  7. Before you buy anything try riding the bike with - out the gas cap. Whizzer has a Carb - Vent problem that will make your bike run as as you have described. I found this out later. Hundreds of $$ later.
    Last edited by a moderator: Jan 18, 2010
  8. RdKryton

    RdKryton Active Member

    I had to drill a small hole in the gas cap to cure a vent problem but I truly believe you have done well to get 1600 miles on a WC-1 engine. They are known for loosing the valve seats within the first 1000 miles. Usually much less! The symptoms are just like you are experiencing too.
    Good luck because a good running Whizzer is a wonderful thing. I love mine. It started out life as a 2000 WC-1. Now it's a screaming NE5.

  9. give me vtec

    give me vtec Active Member

    For what its worth, I highly suggest just sending your engine to Quenton... save yourself the headache and just have somebody that knows what they are doing cure what ails ya. He is a good guy and definitely knows his stuff... in fact he is working on an engine for me right now. Very much looking forwards to it.
  10. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi give me vtec,

    Your replacement head arrived this morning, and I will be completing your motor right away.

    Hi Mennis, Considering your Whizzer WC-1 motor has completed 1600 miles it is possibly a record.
    The only time I found the gas cap vent problem to be an issue was on modified motors that required much higher fuel flow, whereas the stock "restriced" WC-1 motor seldom if ever caused a vacuum in the tank.
    I suggest removing the entire "presure" valve assembly from the cap by bending the tabs on the cap because any changes you make to the motor will most likely cause higher fuel flow.

    Have fun,
  11. built_to_go

    built_to_go New Member

    My whizzer is giving me problems. I bought it drove it about 20miles took it home took off the restrictor in the carb it ran excellent for about another 15miles then gave me problems i just changed the oil and timing and it still is bogging down. I'm lost please help!
  12. built_to_go

    built_to_go New Member

    Its a 99 bought it with 23 miles on it.
  13. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    ALL Whizzers made from 1999 to 2004 WILL develope loose valve seats. Please note I said ALL!!!!!!!!!!!!!!!!!!!!!!!!

    Contact me via Private Message to discuss options to keep your Whizzer working correctly.

    Check air filter as it will most likely be full of oil from exessive crankcase pressure.

    Don't go far from home as loose seats will make you wish you didn't.

    Have fun,