"Thumper" is down for the count (temporarily)

Discussion in 'Whizzer Motorized Bicycles' started by KilroyCD, Apr 18, 2009.

  1. KilroyCD

    KilroyCD Active Member

    I had something happen to me today that was a real bummer. I was riding "Thumper" in to work this morning, and was literally halfway into my 13 mile ride when I approached a stop sign. I had been cruising along at 30mph the whole way, and when I left off the throttle and pulled the clutch and brake levers in, all heck broke loose! It sounded like ball bearings were thrashing around in the crankcase! I hit the kill switch and quickly pulled off the side of the road. I went to wheel the bike into a parking lot, and despite pulling both the clutch lever and compression release, I still had to pick up the back end to wheel it there. I called in to work and had them despatch my boss in the pickup to "effect a rescue", so to speak (that was embarassing). In the meantime, I started to try to find out what was wrong. I pulled the belt cover off and turned the flywheel. Everything felt normal. I turned the clutch pulley. That didn't feel at all right. So I looked things over, and lo and behold, the clutch pulley bearing had literally disintegrated! My clutch pulley was no longer even close to being square with the belt, it was toed inwards about 10 degrees and downwards about 10 degrees as well. The angle was totally cattywhompus! The ball bearings I heard and thought were thrashing around in the crankcase were actually thrashing around the belt cover! After getting to work and unloading Thumper from the back of the pickup, I was able to get the engine started, and to my relief it purred like a kitten. Unfortunately, my boss rode me about it all day (good naturedly, though), calling the bike a "Fizzer".
    "Thumper" is back home now, and fortunately my brother Jim had converted his Whizzer to an auto-clutch, so he had a spare clutch pulley and bearing that he brought over this evening. Maybe tomorrow after the inaugural EZM rides with "Bluebird", I'll get to work on "Thumper" to get him back on the road.
    Has anyone else ever had a clutch pulley bearing explode like that?

  2. Hal the Elder

    Hal the Elder Member

    Sorry to hear that, Chris...

    ...I'm waiting to hear the discussion on the breakdown.

  3. bill green

    bill green Member

    Hi Chris I had one (new) make bad noise and replaces bearings with skf sealed bearings..Bill
  4. jbcruisin

    jbcruisin Member


    cattywhompus? Wow how did you know how to spell that? I know the word but never saw it written. Hope you get back on the road soon.
  5. KilroyCD

    KilroyCD Active Member

    Huked on fonix wurked for me! :grin5:
  6. KilroyCD

    KilroyCD Active Member

    I've been working on a vintage bicycle restoration for the past week, so while literally watching paint dry I decided to pull "Thumper" out and address the clutch bearing problem. Once I got the belt cover off I started to closely assess what was wrong. I soon discovered that the cattywhompus angle of the clutch pulley was not caused by the failure of the bearing, but of the loosening of the nut that holds the clutch arm. As a result, it was quite loose. The noise I heard (that sounding like ball bearings thrashing around) was actually the pulley contacting the plate for my belt tensioner. I took the belts off, lined everything up, tightened everything back up again and put the belts back on. Lo and behold, everything worked! Instead of watching paint dry, I put a couple miles on "Thumper". :grin5: :grin5: :grin5: :grin5: :grin5: :helmet:

    Now back to more painting...
  7. jbcruisin

    jbcruisin Member

    If I remember right you have the slip clutch & Jim has the auto clutch. My auto clutch blew (is that a word?) & I put my slip clutch back on a few weeks ago. It works okay & I might just leave it on.
  8. KilroyCD

    KilroyCD Active Member

    Jay, I think Jim is starting to have the same thoughts, as he hasn't been able to get his auto clutch dialed in properly yet.
    I really like having the slip clutch, but need to tighten my "singing belt". When the clutch is pulled in, it sings like Beverly Sills. :grin5:
  9. Hal the Elder

    Hal the Elder Member

    I hope not...

    Beverly Sills passed away on July 2, 2007.

  10. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Guys,

    Just wanted to let you know I put several auto clutches through some serious tests over the last several days. I made a special version of the 3rd Mel. clutch for my 20" Sportsman racer and it worked much better than expected. 66 MPH on the street [in a 55 MPH zone] and 64 MPH on the Roller Road. The special Whizzer clutch used for the Dirt Drags did change to a bright blue color near the end of the event but still connected very well [yes, Jay it still pulls wheelies]. I will attach a picture of Gerd Lowack's 3rd Mel. clutch mounted & supported like it should be.

    Have fun,

    Attached Files:

  11. KilroyCD

    KilroyCD Active Member

    Not down for the count anymore!

    "Thumper" has been down for the count since the East Coast Rally at Cape Henlopen last year. The clutch and drive belt pulleys were at odd angle and were causing the belts to shriek like I was strangling a cat (or two) when starting out. Just ask anyone who was at Cape Henlopen or even those in the next zip code. I'm sure they heard it during last year's rally. It turned out that the clutch arm was out of square so during the winter I decided to grind it square. To my amazement, all went well. But I was still having issues with the pulleys being at a cattywhompass angle. The other day I pulled the bike out and decided I was going to get things solved.
    I quickly discovered the cause of the continued pulley wierdness. I had forgotten to completely tighten the bolt holding the pulleys to the arm (doh!).
    I got that taken care of, adjusted the clutch cable and then turned my attention to the sticking throttle. Oh yeah, the pulleys weren't the only problem.
    After some minor disassembly I discovered that the little rubber gasket that sits under the throttle cable cap was misaligned, and once properly aligned my sticking throttle went away. Things are looking up!
    Now, it was time to change the oil. Why can't I ever change my oil without spilling some of it? At least it wasn't as bad as this time: http://www.motoredbikes.com/showpost.php?p=133841&postcount=1
    Next, I decided to address the brake light. My tail light worked, but my brake light didn't. I had a new LED tail/brake light bulb that RdKryton gave me, so I decided to put that in. After starting it up the bulb flickered twice and then I had no tail light or brake light. Okay, it must have been a bad bulb. So I got a twin pack of standard 1157 bulbs and tried them. Neither one worked! It's gotta be something else. After troubleshooting much of the aft electrical system I took the license plate off and discovered the ground wire connector behind it came undone.
    I fixed that, put everything back together and the lights now work. Now Thumper is running (and riding) like a champ! Now I can't wait to get it inspected so I can ride it around more.
    Last edited: Jul 13, 2010
  12. RusticoRay

    RusticoRay Member

    Happy for your success's with Thumper. Hope to see you and Thumper at Jay's rally.
  13. azbill

    azbill Active Member

    good to hear Chris :)
    congrats on a good repair
  14. jbcruisin

    jbcruisin Member

    My bike has the manual clutch also. I have to tweak mine too. My problem is that the belt screams when the clutch handle is pulled in at traffic lights & stop signs. See you August 7th.
  15. KilroyCD

    KilroyCD Active Member

    I'll see if we can compare notes to get yours a bit quieter. See you then!