Whizzer J Motor Valve Noise

Discussion in 'Whizzer Motorized Bicycles' started by ColsonTwinbar, Oct 6, 2013.

  1. ColsonTwinbar

    ColsonTwinbar New Member

    Been riding this bike for about 2 years and its made a ticking sound the whole time, a motor guy heard it and thought it was a broken valve spring, but checked it out and springs are still intact.
    I haven't verified which valve it is but when I take the cam shaft out, the exhaust lifter feels firm and stays in place. While the intake lifter drops down, touches the camshaft axle and can be moved up and down freely. I don't know if this play is normal and could be the source of the noise. I can verify today which lifter the sound is connected to.



  2. ColsonTwinbar

    ColsonTwinbar New Member

    I was unable to verify which valve the sound is coming from as it is only made when the engine is at the end of its fourth stroke when the exhaust is closing and the beginning of the first, when the intake is opening.
  3. WZ507

    WZ507 Member

    After watching the YouTube video of the engine rotating with the cam cover removed, it seems like such a loud and obnoxious noise that you should be able to pinpoint exactly what is impacting what, or where the in the system the lash is occurring that is causing it. Have you removed the valve cover and touched both lifters while the noise is occurring? Can you feel the click in one or the other of the lifters? Do the cam lobes look nice or show any unusual wear? When the cam is out can you see anything unusual about the bottom face of the lifters?

    If you watch the mesh of the cam and pinion gear very carefully, can you see the lash and reversal of lash as the noise occurs near TDC at valve overlap. Every Whizzer has a slight click at this point as thrust is reversed on the gear set, but nothing like what you are hearing, at least not in my experience.

    Based on the video I assume the noise occurs constantly (idle, or high speed)?

    Of course the EX lifter has the decompressor washer on it so it can't fall down like the IN lifter can. Have you had the valve cover off and verified that the valves are lashed correctly, that the decompressor washer is mounted tight, etc, and that there is no interference in this area between the decompressor washer and the decompressor arm when it is fully disengaged?
    Last edited: Oct 7, 2013
  4. ColsonTwinbar

    ColsonTwinbar New Member

    It seems to make it all the time but increases in volume when cruising up small hills and at top speed. Heres a clip of it running on a stand from a few months ago, it is quite loud in the garage but you can still hear a pretty noticeable ticking. I haven't had the cylinder head off since I built it, but i have looked at the lifter tolerances and that all checks out.

    I'm trying to get it down to Jim Brighton in Seattle to take a look at one of these days and I might just have to wait for that.

    PS I've been on this forum for 4-5 years under a different username that I could no longer access. So some of you might recognize the bike.
  5. WZ507

    WZ507 Member

    No link attached!
  6. ColsonTwinbar

    ColsonTwinbar New Member

  7. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Check the clearance of the lifters in the crankcase. The vintage Whizzer company made several changes to cause the motor to lubricate the lifters, including a small groove in the crankcase. I have rebuild several hundred Whizzer motors and sometimes the lifters are very tight in the lifter bores, and sometimes the lifter bore is O.S. due to lack of oil. Try removing and swapping the lifters in the crankcase [can be done by removing camshaft, lifter bolts, washer, and nuts, and remove lifters from the bottom]. Be sure to transfer the exhaust lifter washer in the process. If the exhaust lifter is too tight the sound may be coming from the lifter as the valve spring "snaps" the lifter back against the camshaft lobe.

    It is also possible the noise is coming from a loose rod [worn bearings], as this is the most common issue with vintage motors.

    Have fun,
  8. ColsonTwinbar

    ColsonTwinbar New Member

    Thanks again Quenton, I will investigate the lifter situation. I don't think it is the rod and crank are new and are in good shape, there is no sound when the cam shaft is removed.
  9. crazycrawler

    crazycrawler Member

    Hello, would anyone know what the clearance is between the connecting rod and the crank on a Whizzer H motor? I'm taking an engine apart and found that the rod is somewhat loose on the crank. Also, if anyone has info on the stock crank journal size is, that would be helpful. I have a Whizzer service manual but those specs. are not in it. I think I might need new bearings
    and want to order the right size if possible. Machining may be necessary, but I'm not sure yet.

  10. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    The crankshaft pin should be .999".

    Most likely you will need to have the crankshaft rebuilt, just check the journal [pin] and make sure it isn't out of round more than .002". Also look for any deep scratches on the journal.

    It might work OK if slighty loose, however it will be noisy.

    DO NOT try to make inserts fit better by sanding or grinding the rod cap!!!!!!!!!!!!!!
    About one out of ten motors I rebuild have the rod cap reduced, please don't try this as it cost extra to have the rod re-sized.

    The most common regrind is .020" under size, and inserts are available to go as far as .050".

    Have fun,