From: ramarren@apple.com (Godfrey DiGiorgi)
Newsgroups: rec.motorcycles
Subject: Re: 80/81 CB750 s
Date: 9 Oct 92 17:34:48 GMT
Followup-To: rec.motorcycles
Organization: Apple Computer

>I was wondering if anyone could tell me a little about these in
>their various incarnations, i.e. the custom, the supersport the F,
>the K, etc. which is wich, and any useful info would be
>appreciated as I may be buying a pair (a custom and a supersport) 
>Also which 750 looks kind of cafe racerish with the springy
>looking fork covers?  Mentioning any features, or problems would
>be really helpful.  

K was standard bike - wire wheels, single disk, 4 piper
C was 'custom' ... more chrome, glitz, comstar wheels, dual disk 
F was supersport - sportier styling and uprated suspension, 4->2
  exhaust, triple discs, comstar wheels. 

I had a '79 CB750F, my brother still has an '81 CB900F. The F series
of the bikes are the most appealing to the sporting rider, having 
slightly better breathing engines and exhaust, sportier styling,
and uprated suspension components. I never experienced the wobble
as mentioned by someone else when riding a K model, but it was 
heavier and I didn't like the ergonomics.

The F models in the US had somewhat upright seating positions, 
terrible without a windshield, but there was (might still be, if
I know Honda) a 'Eurosport Control Package' available which 
relocated the footpegs and controls, nice forward lean bars and 
all the proper cables, etc. to fit perfectly. Equipped this way,
a 750/900F is a real comfortable bike for any kind of riding.

Engines were strong, double cam, 4 valve aircooled design. They
had a little bit of problem with cam chain tensioner setup and 
at high mileages would tend to seep oil a little until you 
replaced the gaskets. Very reliable overall and easy to maintain.

Emissions adaptation of the time period made the engines very 
peaky and somewhat flat in the low and midrange when stock. Given
a few days of experimentation and a lot of jets to swap around, 
I found that I could take a stock machine, put a K&N air filter
element in the airbox, and adjust float levels, primary/secondary
main jets, needle position and effect instant starting, super
torque and power over the entire rev range. Even when I checked 
the emissions with an exhaust gas analyzer, it was well within
spec. My 750 was easily 10-15% more powerful than the factory
settings and utterly without temperment. (sure wish I still had it.
and gads they factories are doing this so much better now!)

Suspension was par for the time period. The 80/81 series had better
shocks/fork dampers/swingarm pivots than my '79 (which I uprated
in a couple of ways). Wheels were somewhat narrow, which limited 
the amount of tire you could use, but handling was solid and 
sure right up to 125 or so on my 750. A small fairing helped some
to keep the wind from inducing a wobble over 100, but I preferred
the feel of the bike without a fairing.

A great machine; the CB900F of '81 was about the best of that line.
If you can find a good, clean stocker, they go for dirt money and 
are worth every penny.
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Godfrey DiGiorgi - ramarren@apple.com  | DoD #0493      AMA#489408
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