Year: 1981
Make: Kawasaki
Model:  ??
VIN: KZ750?-000001 ~
Engine: KZ750?E000001 ~
Colors: Luminous Midnight Diamond Ruby Clear

Characteristics that distinguish the ’81 750 from the previous years of 750 twins:  For starters, it doesn’t exist.  Yep, this page is somewhat of a parody, and not a very good one at that.  But you have to admit the “Colors” line above is pretty funny…  …in Kaw Twin humor.

Anyway, the truth is that there is some scant evidence to suggest that the ’82 M1/CSR was intended to be released for the ’81 model year;  most notably that it is described exactly as such in one of the printed manuals I have.  That, and the fact that there was only one year with no 750 Twin in the whole model line run (’81), and then the next year there were, for the first time, three of them (M1, S1, Y1) with enough stylistic variances and generational similarities to suggest that they might have been intended as the M1′s successors… In my opinion.

Or maybe Mother Kaw was just waaay too busy with her brand new baby, the 750-four, which was released in ’80, hoping to mitigate further confusion between the models for one year…  Hmm…

Or maybe I’m just way into conspiracy theories.

Year:   1980
Make:  Kawasaki
Model:  G1
VIN:  KZ750G-000001 ~
Engine:  KZ750BE046201 ~
Colors:  Luminous Ruby Red

Characteristics that distinguish the ’80 G1 from the previous 4 years of 750 B1 – B4 twins:  Quite a bit!  The paint color and stripe changed of course (the pinstripes are similar to the ’79, but without the rear-tank downward turn), mag/cast rims instead of spoke wheels, drilled disc rotor, shorter front fender, decorative Kawasaki logo on triple trees, new headlight bucket and mount, updated-style turn signals, chrome gauge/clocks covers, high handlebars and matching angled master cylinder, shorter megaphone-style mufflers, U. S. carbs had plugged pilot screws, no center stand anymore, stepped seat instead of old flat “bench” seat, smaller side cover with “LTD 750t” instead of older “KZ750″ emblem, chrome chain guard, newer-style 5-way adjusting black rear shock/springs without the old chrome decorative cap, left-side-only grab bar instead of full behind-seat grab bar, drum rear brake, o-ring drive chain, and no exposed rear fender as on previous years.

And there were also a couple important frame differences:  Besides the various welded tabs being different to accommodate the previously-mentioned changes, note that the passenger footpeg mount (also doubling as the exhaust holder) has been modernized to a point instead of a big rounded swoop.

Here are some pictures to help identify the ’80 G1  (all pics are U.S. models; I don’t have any European pics, but I’m not certain there are any outward cosmetic differences anyway).

Year:   1979
Make:  Kawasaki
Model:  B4
VIN:  KZ750B-033101 <-> 046100
Engine: KZ750BE033101 <-> 046086
Colors: Luminous Brown (almost red), Midnight Blue (very dark)

Characteristics that distinguish the ’79 from the ’78:  Not much.  The paint color options changed, and the pinstripe design that was brought to a crisp point at the front of the tank sides, and a downward-turned point at the rear of the tank.  Also, the ignition switch changed to 6 pin from 4 pin, and headlight control switch was eliminated.

This is the last year of the 4-year run of the 750 “B” Twin series, and in a larger sense, it is almost unchanged from the ’78 (though there were significant changes in ’78 from the ’77).  The next year would bring dramatic cosmetic changes, then the years that follow would bring even more dramatic architectural and styling changes…  but at the heart, still that same lump…

Anyway, here are a few pics to help identify the ’79 B4  (all pics are U.S. models, I don’t have any European pics).

Year: 1978
Make: Kawasaki
Model: B3
VIN: KZ750B-25701 <-> 033033
Engine: KZ750BE025701 <-> 033074
Colors: Luminous Dark Green, Luminous Dark Red

Characteristics that distinguish the ’78 model years from the ’77:  Color, pinstripe layout/design (4 pinstripes; 3 green and one gold, merging at the top rear of tank, hidden behind seat front), front brake caliper re-located from the front of the fork leg to behind, new angular front master cylinder, modern stator/generator type (3-phase dynamo changed to single-phase in ’78), needle bearings in swingarm (instead of bushings), combination regulator/rectifier (changed from previously separate units), slight design tweaks in the output shaft assembly, recommended fork oil level, and there is some uncertainty about the recommended spark plug (B6ES/B8ES) between model years as dictated in the Kawasaki Service Manual.

Other model characteristics can be found in the Kawasaki Service Manual.

Here are some pictures to illustrate some of the important noteworthy model identifiers…

I believe this pic below was originally in a magazine review (not sure which):

This is a near-new specimen that shows the green color, the new '78 front master cylinder, the U.S. seat, U.S. rear fender, and U.S. turn signal position

This pic below credited to Garret of KawasakiMotorcycle Dot Org:

This pic shows how the '78 tank pinstripes disappear behind the front of the seat; of course the bike has a removed rear fender and replacement exhaust, but you also clearly see the U.S. - style seat, handlebars, and rear turn-signal placement

I believe this pic below comes from Kawasaki, perhaps from a manual or bulletin:

This pic shows the Euro-style seat strap, longer rear fender/guard, lower handlebars, and rear-most turn signal position; as well as a glimpse at the rear-mounted front caliper

Year: 1977
Make: Kawasaki
Model: B2
VIN: KZ750B-016101 <-> KZ750B-025629
Engine: KZ750BE016101 <-> KZ750BE025652
Colors: Diamond Navy Blue, Diamond Brown

Characteristics that distinguish this model year from the ’76: Common, indented right sidecover (changed from non-indented in mid-’76 model year, and would remain indented for the rest of the “B” model run), starter lockout switch, color, and the ’76 tank pinstripe is rounded at rear, whereas on the ’77 the pinstripe comes to a sharp point at the tank side rear.

Characteristics that distinguish the ’76 / ’77 model years from the ’78 / ’79: Round front master cylinder, front brake caliper mounted in front of the fork leg (mounted behind the leg in ’78), 3-phase dynamo (changed to single-phase in ’78), separate regulator/rectifier units (changed to combo in ’78), and bushings (changed to needle bearings in ’78) in the swing arm. In ’78 there were also slight design tweaks in the output shaft assembly, recommended fork oil level, and there is some uncertainty about the recommended spark plug (B6ES/B8ES) between model years.

Other model characteristics can be found in the Kawasaki Service Manual.

Thanks for KTOF member Loic, here are some great images from a French brochure for the European version of the ’77 B2. Note that the only real obvious differences are the longer rear fender, the rear turn signals moved to the rearmost position, metric “clocks”, the “z750″ naming, the seat strap, and some lighting tweaks for local standards. The best part is that you get a real good look at the stock colors and equipment.

Click on the picture to see the full size image. C’mon, you know you want to….

Page 1 - Here you can see the Euro-style seat strap and blue color

Page 2 - The red color, and a good look at the longer Euro-style rear fender/guard

Page 3 - Note the '76/'77 style front-mounted front caliper

Page 4 - One other important Euro-style attribute is the high, rear-mounted rear turn signals

Page 5 - Here you get a good look k at the Euro-style lighting controls

Page 6 - It's a beaut, isn't it?

Year:  1976
Make:  Kawasaki
Model:  B1
VIN:  KZ750B-000001  <->  KZ750B-014947
Engine: KZ750BE000001 <-> KZ750BE015032
Colors:  Diamond Red

Characteristics that distinguish this model year from the ’77:  Early non-indented right sidecover (changed to indented in mid-’76 model year), no starter lockout switch, color, and the ’76 tank pinstripe is rounded at rear, where the ’77 comes to a point

Characteristics that distinguish the ’76 / ’77 model years from the ’78 / ’79:   Round front master cylinder, front brake caliper mounted in front of the fork leg (mounted behind the leg in ’78), 3-phase dynamo (changed to single-phase in ’78), separate regulator/rectifier units (changed to combo in ’78), and bushings (changed to needle bearings in ’78) in the swing arm.  In ’78 there were also slight design tweaks in the output shaft assembly,  recommended fork oil level, and there is some uncertainty about the recommended spark plug (B6ES/B8ES) between model years.

Other model characteristics can be found in the Kawasaki Service Manual.

This picture below (now owned by “Chris”, see comments below) features the earliest version of the B1, with the original un-scalloped sidecover.  The bike appears to be fairly true to stock except for paint/stripes, missing grab rail, and an exhaust from a later model (perhaps a G1):

Early B1 with first version of sidecover

This B1 below (owner unknown) has the later ’76 sidecover, with the carved-out spot for the kick start lever at rest.  It appears fairly stock except for a MAC exhaust (with stock headers and cross-over),  and a re-upholstered (and over-stuffed) seat:

Later B1 with scalloped sidecover and stock paint

This B1 below is a U.K. model (owned by “Peter” from many forums, R.I.P.), featured here for the subtle U.K.-specific differences such as a mid-seat seat strap, the “z750″ badge for the everywhere-but-U.S. model name, and rearward-mounted rear turn signals.  Oh, and note the early non-indented sidecover again.  Of course, it is re-painted, has custom-made exhaust (stainless steel, if I remember correctly), case guards, chrome gauge/clocks covers, and stainless brake lines:

U.K. Model B1

NOTE: If you know (or are) the owners of the bikes above, please let me know so I can credit you correctly.