In The Shop: 1975 AMF Harley Davidson Z-90

This is a 1975 AMF Harley Davidson Z-90 that came into our shop for a partial restoration.

The Z-90’s were made for only three years. 1973, 1974, & 1975. They are two cycle, single cylinder, 90cc air cooled motorcycles. They sport a four speed transmission and use a twelve volt electrical system. This Z-90 came in, not running; but that was hardly an issue. We drained the old fuel from the fuel tank, removed and cleaned the carburator, replaced the fuel feed hose, and replaced the spark plug and battery. Just two kicks and the little bike came to life. We tested the charging system, then blasted around our parking lot for five minutes, then back inside and up on a lift.

The customer wanted the rims to be sent out for chrome. We were not having any luck tracking down replacement spokes and nipples, so we soaked the nipples/spokes over night with Spectro rust penetrating lube and carefully disassembled the next day after recording our measurements for offset. The hubs, spokes, and nipples were sent out to be polished along with the front and rear brake drums.

The m/c was leaking oil from the lower left side of the motor. We removed the left side cover and the rotor to replace the left side engine/crank main seal. The right side cover gasket was also replaced. Everything electrical was well intact. However, nothing electrical was actually working. This was contributed to a handful of corroded grounds/grounding points which were cleaned up along with the taillight and turn signal sockets. Other than the battery, the front brake light switch was the only electrical component that we could not revive, so it was replaced.

With everything back from the “chromers” and the polishers, the front and rear wheels were re-laced and then set in the truing stand to be trued.

And finally, back out in our parking lot for a few more laps.
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7 Responses to “In The Shop: 1975 AMF Harley Davidson Z-90”
  1. Dean

    Bought a clean 1976 SS175. Had the gas tank cleaned of rust and sealed with Caswell epoxy. Replaced chain and sprockets (Used sprockets}. Replaced rear wheel bearings and repaired voltage regulator connectors. Replaced turn signal lenses and bulbs etc It was titled out of state and got it registered, titled and insured in California. I have driven it 1200 miles in the last year

    • Robert

      Did you use stock wheel bearings or did you find sealed bearings as replacements? I’m asking because I’m working on a ’76 SS125 and want to replace the bearings with sealed ones, if possible. So far, I have been unsuccessful in locating such bearings that will fit this model.

  2. marklewis

    that’s what i like to see; restore ’em & ride ’em, don’t crush ’em!!

  3. Rick Halley
    Rick Halley

    I’ve never owned anything but a Harley. Z90 was my first bike back in ’72. Great to see one again.

  4. Art

    Nice Re. Store on the 90, i been lookin for a left rear turn signal with the weld bracket. Any idea’s…. thank’s art

  5. Ken Osterloh
    Ken Osterloh

    Hello , my name is Ken Osterloh and I saw the bike on your website. I was so excited , I had the twin to this bike in 1981 on our farm in Iowa. Was wondering if the client might sell this bike , would love to have a piece of my childhood .
    I can be reached at 682-433-9273
    I have a picture of me on my bike on our farm from 1981 I could share .
    Thank you for your time .