Topic: Ouch! CB750 F1 a Biking Lemon?!

[lordmoonpie]

So, there I was flicking through the latest Classic and Motorcycle Mechanics magazine on this side of the pond and in the Biking lemons section - the CB750 F1!!

It's a fairly damning write up about a slow heavyweight bike with bad styling and paint thrown in. Not having owned an F1 I wouldn't know - are they really all that bad?!

[UnCrash]

Not if you like the looks of this ---->




Or this



Beauty is always in the eyes of the beholder.

Its no more a lemon than the K5 was.  Valve guide wear was repaired free of charge at the dealership if it became an issue.

[Steve F]

So, there I was flicking through the latest Classic and Motorcycle Mechanics magazine on this side of the pond and in the Biking lemons section - the CB750 F1!!

It's a fairly damning write up about a slow heavyweight bike with bad styling and paint thrown in. Not having owned an F1 I wouldn't know - are they really all that bad?!

An "F1" would make it a '76, and I beg to differ.  It may be a little on the "heavy" side, but both of mine are rock-solid reliable.  Is there some sort of a link to this article that is mentioned?

[goon 1492]

Not if you like the looks of this ---->




Or this



Beauty is always in the eyes of the beholder.

Its no more a lemon than the K5 was.  Valve guide wear was repaired free of charge at the dealership if it became an issue.

Man uncrash those are nice lookin scooters! I like those super drilled rotors.

Your wrong in your avatar text though, because where theres a will theres always a relative , sorry had to say it.

[Jerry Rxman Griffin aka MuthaF'er]

Lemon my ass!! The supposed rebirth of the 750. I wouldn't have bought a 750 if it weren't for the introduction of the F. After Honda dogged down the original and they ran like a fast 350, there was no way. I got tired of the 500 Kaw smoking the 750. When the F came out I had serial number CB750F-1001606. Ran MUCH better than a K5, handled better, double discs, etc. I had 2 buddies with 500 Kaws that got half tracked by my new F. Some of the reasons I still own my original "LEMON". 

[MatthewH]

I was wondering when someone would bring this up, I also read this article, which was total horse-s**t.  If you look in the index of that copy of the mag, you see it tells you they were originally planning a "biking lemon" article on a completely different bike, an MZ if I recall, but must have changed it at the last minute - and forgot to change the index reference.  Suggests a rather hastily cobbled together article I think.  Add that to the fact that only a few pages earlier in teh very same issue, they're celebrating the 40th anniversary of the "birth of the superbike" with the K series CB750 bikes, it's a bit inconsistent.  It's beyond me how the guy can moan about the braking of the F1 given it was updated with 2 discs. Dur? 
That magazine has really gone downhill since the guy took over as acting editor.  Honestly they couldn't proof-read their own names -  there are so many mistakes in it.   

[Geeto67]

I have met a lot of "blokes" from the UK here in the states that feel that the 75-76 F bikes were castrated cb750s, so it is not an uncommon opinion. Some of those guys are kawasaki triples guys also (Ask the famous Rick Brett about cb750F's and he'll give you an earful about how they suck)  so I don't know about their credibility, but at least it is not an opinion that I am hearing for the first time.

Yes the bike is heavier than the original K, and some don't like the bodywork. It is all a matter of taste. Really honda created the F bikes to keep the cb750 competetive, the KZ was faster but the honda had more speed parts and better brakes (shock of shocks considering how bad they are), the GS was slated to come out in 76 and it had a rear disc so honda was just trying to get a jump on the competition. It was a bandaid fix but really the cb750 was already a great bike so bandaids made them all the better.

[GroovieGhoulie]

Well, the F had improved frame geometry and suspension for better handling, the rear disc brake, and the engine was massaged to get it back to the original 68hp, since the K bikes were reportedly down to around 53-55hp at the time.  The only controversial issue I think is the styling, (in the eye of the beholder, I like it), and the fact that the bike picked up some weight, 505 pounds dry versus the Sandcast's 480.

I have a Cycle period test on an F1 and they reported much better handling than the last K they tested, which was a K5.  They reported the rear brake was so powerful it needed care or it would lock.  Perhaps why Honda "detuned" the rear disc brake to a single-piston in '77?  They also dyno'ed it for rear-wheel HP and it made an even 60, compared to the K5's 49-and-change.  11hp more from the same displacement is no joke.  The said it had a new cam, higher-compression pistons, new gearing and other changes.  The downside was decreased fuel mileage, they recorded an average 38 MPG versus mid-to-high 40s for the K5.  The F1's RWHP numbers figure right into 67-68hp at the engine.

Despite the weight-gain, the F's performance was better too: Quarter-mile in 13.1 @ 103mph compared to the K5's 13.7 @ 98mph.  Over half a second and 5mph trap speed is impressive for a bike that supposedly was more a styling exercise than anything else.  They also reported a true 125mph top-speed compared to the 115-ish of the K5.  Thank the F's "higher" redline, which started at 8500 and ran to 9200, just like the K0, before Honda lowered it to 8000 to 9200.

I would argue that the F0 and F1 are the "best" of the 750s.  The power of the early bikes, but matched to improved handling and braking, and with six years of engine development to smooth things out such as plug-fouling and idling issues.  I love my Sandcast, but it feels "high-strung", doesn't like to idle and fouls plugs every couple-thousand miles.  The F will start and idle all day, and still run with the "fastest of the 750s", the Sandcast.  Yeah, the styling is controversial, but after owning it, (and HATING it at first), I actually have grown to PREFER it to the K-models.

The F models DO seem to have a cult about them.  Either you love it or hate it.  As for me, well...

CB750F1 Super Sports for LIFE. 

[KB02]

I loved my F1. It's a shame I had to sell it, but I needed the money to buy a house.

The greatest things about it is that even though I had "cafed" it out, it was my daily rider when I was having issues with my 24 year yonger Ducati. I rode the snot out of that F1, too. I determined that it liked to be ridden agresively... so that's what I did. 

[Geeto67]

68 hp seems pomistic for the 75-76 cb750ss, are you sure you are not thinking of the 77-78 cb750s which got big valve heads? I have heard the 68 hp number in connection with the F2 but never the F1. I own a couple of 75-76 F bikes and K bikes and really they don't feel any different performance wise from their K sisters.

BTW the 75-76 K bikes were getting 53hp at the rear wheels, I don't know where you are getting that as a flywheel number but I have had my stock k5 on a dyno and that is about what she pulled (52.6 actually). I had a buddy with a 74 and he pulled 53 and change. I don't think honda was releasing hp info for those bikes after the k0 models as it was trying not to advertise a drop in hp.

If I get access to a dyno again I may dyno both bikes back to back and compare.

Honda switched to the 77-78 brakes because the older brakes would not fir the comstar wheels and at the time they were trying to standardize certain parts through out their lineup. The 77-78 rear brake is every inch as good as the 75-76 rear disc with a lot less weight and the 1982 twin pot calipers cream both of them (and can be adapted to 77-78).

[GroovieGhoulie]

I have one of those "Gold Portfolios" which reprints all the old articles on a given machine, and according to period articles, the later F2 and F3 bikes were said to have 72-73hp thanks to the bigger valves, (but still lagged behind the Suzuki with 76hp).  The articles dealing with the F0 and F1 all said the performance was head and shoulders above the same-year K bikes, but they all pretty much hated the styling, likening the F1 muffler to the "unholy union of an expansion chamber and a big Harley pipe".

For me, the enjoyment of these old bikes is about the riding experience, and the difference between low-60s hp and high-60s hp is academic and splitting hairs.  I was just reporting what moto-journalists were saying back in the day and comparing my own experience on my F1 versus my K0.

The single biggest change in the bike's performance I think was the gearing.  The F had a slightly shorter primary ratio and marginally shorter 2nd, 3rd and 4th gears along with 17/48 sprockets.  In a direct comparo with my brother's K3, both engines feel about equally strong, (with the F's 4-into-1 exhaust being quieter), but the K3 feels overgeared, while the F feels more lively.  I think a K geared to 17/48, (which is mathematically damn-near the same as the original-spec 16/45) would be ideal.

[GroovieGhoulie]

Slightly incorrect in my last post.  Only 4th and 5th were shorter.  Culled from an old post of mine referencing the gear ratio differences:

----------------------------------------------------------
Gearbox Differences:

4th:

K - 1.097:1
F - 1.133:1

5th:

K - 0.939:1
F - 0.969:1

Gears 1-3 were identical.

Combined with the overall gearing changes (sprockets) from the K, the overall drive ratios are:

K:

1st - 11.38
2nd - 7.78
3rd - 6.07
4th - 4.99
5th - 4.27

F:

1st - 14.01
2nd - 9.57
3rd - 7.47
4th - 6.35
5th - 5.44

Source: Cycle Guide Road Tests of 1975 K5 and 1976 F1.

[crazypj]

I was working in a Honda dealers in 1978 so worked on a lot of the earlier bikes. ( K0~F2~DOHC)
 Most people in Britain who had CB750's treated them as a large comfortable 500 with great torque rather than a hot 750. (by the mid/late 70's)
Personally, I liked the styling of F1, the K series were starting to look old ( hell, I was 21)
The only problem with the brakes was actually a fork problem.
 Aftermarket tyres were good enough that the front wheel didn't lock up (on a dry road without loose gravel etc) but the forks would bend far enough under heavy braking for fender to touch head pipes.
I personally never found a great deal of difference in performance between the F1 and F2, when you got them rolling around 80+mph, two up with some camping stuff they felt pretty much the same ( F2 brakes were slightly better, forks bent further and put bigger dents in front mudguard) 
pj

[lordmoonpie]

Maybe it was just the yellow F1s he didn't like - the F2s he says are good bikes. No accounting for taste eh?

Not sure the article will be online and free yet but it will eventually appear at www.classicmechanics.com

Actually - I think the Morton's empire as a whole is losing its way - a musical chairs kinda thing with editors and Rod Gibson off ill has left all publications suffering ill-conceived changes. Not good!

[cben750f0]

i quite like my F1

lol



peace

[Clyde]

Honda made about 15,000 75F's (only sold in the US) and 40,000 76F1's

Not bad for a Lemon.

Suzuki sold about 21,000 GT750's in 76 and Kawasaki sold 40,000 KZ/Z900's in 76 and 77

[OhItsBob]

So is that what that dent on my front fender is all about?

[JohnG]

I bought one new in the Fall of '76 and still have it.  It has about 82,000 miles. Rebuilt the motor last summer.  It has been across country, up and down the East coast and to Canada.

Opinions:

negatives:
* the original muffler was uglier than all hell.
* the original rear disk and pads did not work in the rain.  Honda
recalled them
* front forks were pretty harsh. Got some S&W progressive springs and air caps and they are fine.
* never has idled too well. Clutch rattle and all that.
* side covers were flimsy. Aftermarkets better.


Positives:

*all wiring is original.  The grommet to the rear tail light crumbled a few years ago and shorted that circuit out.  Cost me over a buck to fix.

*charging system is still original.  Supports the 100/90 halogen light I currently have, high output coils as well
*the Candy Antares scheme looks great
*in one configuration I had, it regularly got 55 mpg highway
*carbs much easier to work on than most bikes
* goes and goes and goes and ....

             john

[BeSeeingYou]

I have to say I really love my F1.  I prefer it's look to that of the K bike..  I have to agree with what has been said about the better brakes, handling, and increased HP.  I have tried out a few K bikes (74 and 76) and they have not compared favorably to my F1.  I get a lot of compliments on it when I go to bike gatherings.  Everyone is familiar with the K and they have all seen them over and over so they are curious about mine. 

Maybe I am in the minority but I like the stock muffler.  To each his own I guess.

[MacM2010]

Maybe I am in the minority but I like the stock muffler.  To each his own I guess.

I prefer to think of it not as a muffler, but an exhaust cannon. 

[HondaMan]

I love my Sandcast, but it feels "high-strung", doesn't like to idle and fouls plugs every couple-thousand miles.

I can fix that....   

[Achmed]

I have an F1. It should look like your guys'. But it is a little more "rugged" and "dusty" and "spiderwebby". I have to say it is the best bike in the world. Dang if I can find a new muffler for it, though. I also have a K parts bike and the F looks a LOT better than that one.

It weighs a ton, too. And the side stand is broken off. And the tail light lens is faded to clear now. And. And. But it still rides and goes fast. It has that burgundyish color, like a fine wine. F those Ks! Right in the A!

[cben750f0]

i got my stock system NOS from a small country honda dealer close down, now it is hangin in the shed....lol for when i return the F1 to standard again.

peace

[BeSeeingYou]

i got my stock system NOS from a small country honda dealer close down, now it is hangin in the shed....lol for when i return the F1 to standard again.

peace

That had to be a nice find.  Jerry Rxman Griffin is the king of NOS here.  I think he is trying to build a bike out of NOS.   How is it coming Jerry?

[Jerry Rxman Griffin aka MuthaF'er]

Steve, glad you asked. I can use a little help from our members as I'd like to start the restore this winter.

My list of NOS parts I'm looking for has gotten VERY small with the recent addition of my NOS speedo to go along with the NOS tach. I'd still like to find NOS handlebars. They are the -341 bars for 73-76K and 75-76F just in case someone wants to help out. A NOS chain guard has eluded me as has a NOS rear grab bar aka rear bumper. I also have to find the NOS colored seat trim for blue (both sides) and orange (right side-I have 2 lefts which I'd trade 1) or have a sign shop make the colored pieces to stick on. OR I'd trade a NOS black set for any combination of these. I still need a NOS right side tank emblem too. I have 2 NOS left emblems for which I would gladly trade 1 for. Oh yeah, a trim piece for the rear of the seat cowl would be good too. Other than that I have almost enough to make the second bike except for another frame. As it stands my bike will have the option of being either blue or orange, depending on my mood  


Ben,

How's school going?