Help with Ambassador starter and head gasket?

Discussion in 'Whizzer Motorized Bicycles' started by kagol1, Mar 22, 2012.

  1. kagol1

    kagol1 New Member

    A 'new Whizzer' to keep my originals company!


    I now have a 2008 Ambassador, added to my Pacemaker and my 1964-ish one-off, high--handle bar/banana seat, chain driven Whizzer (I think it's a modified Sportsman frame) - mine since new, and unmodified. Both restored a few years ago.

    I ride only the new Ambassador, and it's not too bad! I can't seem to coax more than 32 mph out if it, with my 185 lbs in the saddle.

    Since new (has 200 miles on it) I see a little bubbling around the head gasket, only until it warms up. Does anyone have a suggestion? Replace the gasket? Head needs milling? Is this contributing to lack of speed?

    Also, the electric starter often fails to engage, just spins, but eventually will catch and start. Ideas?

    Thanks, in advance, for any help!

  2. ranger-ron

    ranger-ron New Member

    I had the same head problem with my ambassador too. The head original had some low spots. I milled the head myself using full sheets of emery cloth and a piece of double strangth glass. Be careful by appling even pressure, turn the head offen and check to make sure the complete surface is flat. I used a marker and put lines/marks on the surface and then check to see if all the marks were removed by the emery cloth. I remove only about .030" plus I decked the clyinder the same way, but that took a while because of the steel valve(s) block. Originally, it was proud of the rest of the cylinder, but now all is nice and even and no more head gasket leaks.
    On your starter problem; it sounds like your 6 one way clutch 'dogs" are not free to engage. Rust? I may be wrong, but I would try some WD 40. Just my thoughts.
    Good Luck, Ron
  3. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Kagol1,

    There are 2 versions of the Ambassador. Ambassador and Ambassador II.

    Both versions share many of the same problems, however version II needs more upgrades.

    The biggest problem is the "automatic compression release" in the head. The release normally self-destructs within a few hours of motor time. The issue is the spring is of such "world class quality" that it loses its temper and become useless in sealing the combustion chamber. The normal fix is to remove it and replace with a short [same amount of threads as the compression release] 10 MM fine thread bolt. It won't take long to notice the bike starts easier without the "leaking" compression release. If locating a 10 MM fine thread bolt is a problem, simply use a short 10 MM spark plug with an extra washer.

    The cylinders weren't "cured" correctly and the head bolt threads in the cylinder will most likely shear. Only a few had the valve "block", and most don't have the problem of the block and or screws hiting the edge of the combustion chamber in the head.

    In order to make the top end stay together, many upgrades should be done as soon as possible. All versions of the cylinders used on the Ambassadors & NE-r models must be "decked". The block versions will need to be started on a "belt" sander to level the block, and screws even with the cylinder. The non-block versions will still need to be "decked" to remove the deep tool marks on the top of the cylinder. The head needs to be milled at least .065" [I have several milled over .090"].

    All head bolts should be replaced with high quality grade 8 or higher. 2 special washers should be fabricated to fit under the two 10 MM head bolts. The cylinder should be placed in an oven at 325 degrees for 3 hours and let cool normally to soften the aluminum in the cylinder [to stop threads from shearing]. Valves must be removed prior to placing in oven.

    Open side cover and advance camshaft one tooth [most are set at two advanced, DUMB, really DUMB]. Set lifter clearance at .006" intake, and .008" exhaust. These changes will most likely raise your top end approx. 10 MPH.

    Also note the speedometer is way off because of the larger 3" tires. It is off about 10%. 32 MPH = 35.2 MPH.

    The starter on the later Ambassador II has had issues with the shoulder the starter drive rides on. The long bolt that holds the CVT, and starter drive wheel can also unscrew, check to make sure it is tight. The starter drive system uses a one-way sprag bearing to enguage the drive, and sometimes the hub shears from the shaft [employs small teeth with hub pressed on] and causes the drive to spin without turning the motor. Also use a light grease on the five internal pins [not oil].

    I haven't covered the starter drive on the Ambassador as it was a very low production run and only a few were sold. I have one of the first Ambassadors, and it employs a different starter drive system, and I can provide information if needed. The original new edition Ambassador is easy to identify as it uses the automatic clutch, not the CVT drive.

    Have fun,
  4. kagol1

    kagol1 New Member

    Ron and Quentin,

    Thanks for the quick replies and advice! Looks like I have a project about to start - if I decide it's in my skill set!

    Happy riding to you.

  5. kagol1

    kagol1 New Member

    Quentin, one quick question, please. I have a CVT. Does that mean my bike is an Ambassador II?


  6. ranger-ron

    ranger-ron New Member

    Per Quentin's advice, I cured my cylinder in the oven and then sprayed it with a heat resistent semi-gloss black. It helps it run cooler plus it really makes the engine look nice too.
    I chose the conservative route and decked my cylinder by hand rather then using my belt sander. Believe me, I know how much damage a belt sander can do if your not very careful. Besides, I didn't have anything going on that day ;-).
  7. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Guys,

    Yes it is an Ambassador II, very few Ambassador model were produced. I have one of the very first Ambassadors with the automatic clutch. The Ambassador is much faster than the Ambassador II because of the larger 22 MM carburetor, original NE head, and modified automatic clutch. My Ambassador only takes the speedometer to a little above 50 MPH [50 MPH with larger tires = 55 MPH].

    I only use a belt sander to level the cylinder with the valve block as it takes way too long to work the block and mounting screws level with the top of the cylinder. I then place #220 sand paper on a granite block and work the top level by hand.

    Have fun,
  8. kagol1

    kagol1 New Member

    Thanks to Quentin and all who have replied! You guys are great and I should have joined this site long ago.

  9. ranger-ron

    ranger-ron New Member

    "Open side cover and advance camshaft one tooth [most are set at two advanced, DUMB, really DUMB]"
    Quenton; The cam on my Ambassador is advanced 2 teeth, but it seems to run very well, so I left it there for now. Will I have more torque in part or all of the power band if I retard it so it is advanced only 1 tooth? Please elaborate on how it will improve runability overall. Thanks, Ron
  10. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Ron,

    Needs to be set one advanced. Set correctly will add RPMs to the top end.

    Try it both ways and notice the difference.

    All my motors are set one advanced, one turns over 8000 RPMs. Average is about 6000 RPMs.

    Have fun,