What Next...Carb Mods or Mushrooms?

Discussion in 'Whizzer Motorized Bicycles' started by Hal the Elder, Jan 5, 2009.

  1. Hal the Elder

    Hal the Elder Member

    Well...I've got my intake restriction opened up to match the carb venturi and the intake port, and I've got a Hi-Flow muffler insert installed, and I've got the cam gear advanced one tooth.

    What should my next priority be...Re-jetting the Carb or ordering the Mushroom Valve Lifters?

    My throttle response seems to be OK, but since I live at 3000 ft. elevation, (where the air is thinner), do you think this would cause my fuel/air mixture to be a bit on the rich side?

    Thanks...
    HAL & OSCAR
     

  2. KilroyCD

    KilroyCD Active Member

    Hal, I'm going to make this suggestion because of my lifters going bad in less than 300 miles. Do the mushroom lifters first, then worry about the mixture. You may also find that (if you take care of the mixture first), because the 'shrooms hold the valves open longer the mixture may need to be changed yet again.
     
  3. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal & Oscar,
    Guess what? Chances are if you change the valve timing [mushroom lifters] you will also effect the air/fuel requirements slightly.

    BTW, we called the machine shop today and asked about obtaining more mushroom lifters. The reply was "we will call you if we get an opening in the near future". We may run out if the demand doesn't slow down. I was only able to get 25 sets for my stock, and I shipped out almost 1/3 of them this morning.

    Have fun,
     
  4. Hal the Elder

    Hal the Elder Member

    Good Point, Kilroy!

    A DANGED good point!

    Mushrooms next, then! (You hear that, Quenton?)

    Thanks...
    HAL
     
  5. Hal the Elder

    Hal the Elder Member

    OK Then, Dr. Q...

    What do you need from me to ship me a pair NOW?

    Thanks...
    HAL & OSCAR
     
  6. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal, send me a PM [private message] with your shipping address.

    Have fun,
     
  7. Kep1a

    Kep1a Guest

    May I also suggest Hal If you are going to do any other upgrades do them now. Before you do your jetting.

    You know like...

    1. Copper head gasket (a must have).
    2. Milling the head .70 for more compression.
    3. Polishing that combustion chamber.
    4. Match porting and massaging the valve pockets.
    5. 3 angle valve job.
    6. machine the spark plug hole for a shorter 10mm plug without the threads protruding into the combustion chamber.
    7. Any other things you may want to do that will change how it performs.

    I have not done all of the above myself but they are things you should consider if you are going to do this proper.

    Then you can jet that thing once and be done with it.

    Note; You also may notice it to be more cold natured once the jetting is done.

    Kep1a
     
  8. Hal the Elder

    Hal the Elder Member

    Hey Kep1a:

    I'm not a performance enthusiast at all...just a Reliability enthusiast!

    I have no appetite for cruising at over 25 MPH, where I feel comfortable. I actually feel the MOST contented at 20 MPH!

    This old man DOES NOT feel comfortable at 30 MPH and above on a motorized bicycle!

    I'll leave my engine strictly stock, with the exception of replacing those components that are prone to early wear.

    That's it!

    Thanks anyway...
    HAL
     
    Last edited: Jan 5, 2009
  9. Kep1a

    Kep1a Guest

    Well the copper head gasket and the shorter spark plug conversion and machining the spark plug hole is a must IMHO!

    But the rest is optional if your head has a true flat surface (mine was not). All the rest really only becomes something to consider doing because you are already that far and at the machine shop anyway. Performance also makes for easy starting, cooler operating temperatures, smoother throttle response and idling. Not all of this is for go fast mods. Some like the plug and copper gasket are upgrades for long term reliability issues on that motor.

    Kep
     
  10. Hal the Elder

    Hal the Elder Member

    Not Interested!

    HEY KEP1A:

    I have no true Machine Shop...it's more like a Hobby Workshop.

    I have no Milling Machine, only a 9"x20" Metal Lathe, a 1/2" Drill Press, a 12" Disc Sander, a 12" Band Saw, a 6" Bench Grinder, an 8" Table Saw, a 3/8" Drill, a 1/2" Drill, a Portable Grinder, a Jig Saw, a Scroll Saw, a large Vise, and an AM/FM/Cassette Player.

    I'm from the non-adventurous school that says: "LEAVE IT STOCK!" I'll bet there are plenty of Whizzer owners who are enjoying their bikes just as they came from the factory.

    I've already made what I hope will be the extent of all present and future modifications to Oscar, except for the insurance policy of the Mushroom Valve Lifters.

    I'll leave the hot-rod stuff like milling the head and polishing the combustion chamber to those younger guys in their 60's who take their bikes to the Bonneville Salt Flats on weekends!

    Thanks again, KEP1A...
    HAL
     
    Last edited: Jan 5, 2009
  11. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal,
    Lifters will leave tomorrow morning. Boy they are going fast!
    A few comments to consider concerning the head, the compression is too low on all of the NE5 Whizzzer motors. If you check it with a compression gauge you will see numbers between 80 and 90 pounds. The motor needs at least 100 pounds to, start easier, idle smoother, better throttle response, and better gas mileage. If you make the spark plug fit correctly in the head it will also run cooler. If you mill the head, the area near the 2 large head bolts will increase and make a much better seal reducing the chances of a blown head gasket.
    I have milled and reworked many heads [over 100], and suggest removing .060" and use a copper head gasket. The copper gasket is thicker than the steel version by .010", so if the head is milled .060", the copper gasket will in effect reduce the difference to .050". The end result will not make it ready for "Bonneville", just put it closer to the correct compression ratio for street use.
    On my race motors, I use special heads with reduced combustion chambers and end up with 165 pounds of compression and need high test gasoline. On my street bikes I usually mill stock heads down .065" ~ .070" and try to end up with approx. 110 pounds of compression.

    Hope this information is helpful,
     
  12. Hal the Elder

    Hal the Elder Member

    I Have No Bridgeport!

    HEY Dr. Q:

    So do I send my head to you for milling, along with my clutch for rebuilding?

    On the other hand, Oscar starts, runs, and idles just fine with the stock compression ratio, and has more power than I need for my preferred casual cruising of the Desert byways at 20-25 MPH!

    But if it's absolutely required for me to have my head milled and my clutch rebuilt, then to be accepted as a "right-thinking" member of this Forum, I'll agree to have it done!

    HAL the REASONABLE
     
    Last edited: Jan 6, 2009
  13. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal & Oscar,

    I can help you with the head later. Main issue is to change the lifters for duribility.
    I have "jigs" made for my mill to address the spark plug length and the milling process. I also rework the combustion chamber for better flow in the same process, but I suggest you leave the head "as is" until you have approx. 500 miles on the motor. I don't want to quote prices, but it is about half of the average machine shop price, because I don't do this for a living, but just for the fun of it.

    Have fun,
     
  14. Hal the Elder

    Hal the Elder Member

    Sounds Fair To Me, Quenton!

    Now, about the payment for the Mushrooms...what is your preferred method of payment, and how much, including shipping?

    I assume the Lifters will take priority over my clutch rebuild...? It will probably take another 4 months to acumulate 500 miles on Oscar!

    Thanks...
    HAL
     
    Last edited: Jan 6, 2009
  15. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal,
    I will include an invoice in the package. Simply mail a personal check [please don't waste your money getting a money order]. I will send it via padded envelope to save money on shipping.

    Have fun,
     
  16. Hal the Elder

    Hal the Elder Member

    That's Just Fine With Me, Quenton!

    Sent those two little pieces of steel right to me, and I'll follow your installation and valve clearance instructions!

    HAL
     

    Attached Files:

  17. Kep1a

    Kep1a Guest

    Good call Quenton,
    My head gasket started leaking at about 350 miles but only when cold at start up. I found the head was no where near flat and was forced to mill it to make a flat sealing surface. When I realized how much of the spark plug threads were protruding into the combustion chamber I knew that was going to be an issue with the life of the threads in the head. It could also create hot spots that would cause knock problems also known as pinging or detonation.

    The replacement plug now fits the chamber perfectly and no threads are exposed to combustion deposits that would tear the threads out of the head while removing the plug for normal maintenance. Re-surfacing the head to be flat again required the removal of about .60 to regain a flat sealing surface. I polished the combustion chamber to remove any sharp edges that may also cause pinging. The improvement in flow will only enhance the engines cooling and overall bike performance. The net effect of these improvements was dramatic on my bike! I only wish Whizzzer had paid attention to the details negating the need for me to do these upgrades.

    I would much rather ride than tinker IMHO.

    Kep1a
     
    Last edited by a moderator: Jan 7, 2009
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