74 Z1F versus a 75 Z1B

Can anyone tell me difference? I have a seller telling me they have a 74 that was manufactured late and has the 75 specs. Title list a 1974 Z1 B.

Sorry, the title list a 74 Z1 F

Do you have any pics of the bike?

A shopping guide, sorry only in German language.



Z1 74 color set



Z1A 74 color set




Z1B 75 color set

The '74's were Z1A's, manufactured between July/73 and June/74. The '75's were Z1B's, manufactured between July/74 and June/75. There were a few (Z1A & Z1B) manufactured at the same time between about May/74 and August/74. There should be a white sticker on the neck with the month and year of manufacture.

There are a few differences between the two model years. Look at the gauges. The tachs will be the same but the speedo on the '74 only registers in 20 mph increments, while the '75 registers in 10 mph increments. The '74 used a chain lube pump (under the left sidecover) to lube the chain. The '75 used an o-ring chain and did not have a lube pump. Serial numbers for the '74 Z1 ended at 47499. Any higher number would be a '75.

There was one for sale in ebay a few weeks ago. Initially they claimed it was a '74, but the S/N was too high and I advised them it was a '75. It was back a couple of weeks later listed as a '75. The letters Z1F are the first part of the frame serial number. The engine will begin with Z1E.

They made changes to the carbs on the 75 Z1b's also. Different slides, needles and jets. My Z1b was just a little quicker than the Z1 and Z1a. That's why Larry went with a 1013 kit and a Kirker 4/1. He was a lousy rider and lost most of the time anyway. :woohoo:
Steve

Slides on the Z1B were 1.5 vs the much larger cutaway on the Z1 & Z1A. This allows use of a smaller pilot jet and provides a smoother idle as air flow is better at idle. The main jet is the same on all Z1 models but they switched pilot jet types for 75 and subsequent years where VM carbs are used. The jet needles are identical 5J9 on all Z1 models (Z1, Z1A and Z1B) but the needle jet is different and has a small diameter hole. The main issue with any Z1 carb is the funky and overly complicated external sync mechanism .