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Discussion Starter #1
Let me start with a disclaimer. I never went hunting for a CB. I have really been avoiding them since they have become so popular. I have never seen the tv show, and I am not building a cafe racer.
That said I just recieved a free 1978 CB750F from a guy I know that just got tired of it. he told me it was a late model and I thought I was getting a DOHC bike and had dreams of building a Freddy Spencer style of racer. well that is not what showed up so now I have to come up with a new plan.
I will be getting rid of the clubmans and reinstalling the airbox when its in my garage(at a different friends shop) after that I don't know where I am going to go with it. I just want a solid street bike I can ride all day.

Educate me on this bike. The good, the bad, and the ugly. Inspire me to do some thing cool with it as my recent vespa project will be done at the end of the month and I will have to fill my free time with something other than beer.

I will post pics when I figure out how,
Thanks,
Billy
 

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Discussion Starter #2
Nothing. Not even a good heckling. Damn, I should have asked how to apply checkerboard stripes and which pomade works best inside a vintage helmet.
Back to the beer room I guess.
Billy
 

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Discussion Starter #4
I am not tough enough to ride that thing around. That gas cap looks menacing.
thanks ,
Billy
 

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I can't say anything about the bike from a hands on practical point, I've never owned one. I can only comment from what I remember from the day. 78 was the last year of the SOHC motor, so you missed the Freddie Spenser option by a year. The 78F was probably the best of the SOHC litter. It had a small assortment of Honda tweeks to make it relevent to the then new Suzuki GS750. From what I remember of road tests of the day, it was a solid performer. Pretty much dead even with the GS in stock form, in all of the practical comparisons. The 76F was a bit of a dog, and Honda freshened it up quite well in 77, with the 78 pretty much just being a change in graphics. The Comstar wheels were nice, as you could run tubeless tires on them. That wasn't a given back then. The cast wheels on the Suzukis had tubes in them, although lots of us converted anyways. In 79 I was looking to get my first 750, and the 78F was one of the bikes I was hoping to get. For me, it pretty much came down to which bike popped up first on the used market at the right price. A 78 GS750E was what I ended up with. If I was you, I'd try to get your F back to stock. Not a bone stock resto, but a practical usage stock. Like many of the UJMs of the day, it would still be a great do everything kind of bike. Of course, at this site, and my own tastes too, I'd lean it in the cafe direction.
 

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I have owned a bunch.

Mileage is key with these bikes. Honda put big valves into them and reworked the head to get the extra ponies out of them. They did however cheap out on the valve guides and most if not all usually chew up the stock original guides at around 30K miles. Earlier if beaten on, later if babied. If you have one over 30K and it isn't smoking yet consider yourself lucky. If it is under, just ride it till it does.

Honda used different pistons with the big valve heads, which means none of the hop up parts like big bore kits will work with the 77-78 motors.

On a positive note, the kehins on these bikes were copies of the vm mukuni's that suzuki was using on the GS, complete with accelerator pump. As long as the pump is in good working order those are excellent carbs.

the earlier cb750s when you thrashed them had a small output shaft that would flex and toss the chain. For 77-78 honda increased the size of the output shaft, which means 77-78 bottom ends are bullet proof, as long as regular oil changes are kept up. Honda also used a 630 chain, but you can drop back to a 530 if you want.

while the disc brakes are an improvement, you can use DOHC twin piston calipers from the 1981-82 750F and 900F as long as you grab the fork mounting brackets from those years as well. If you don't like the silver comstars, you can grab the black and sliver "reverse comstars" from those years as well (or the 1100F cast wheels or the boomerang comstars used on overseas 1100Fs and cx500 turbos front only). If you are going to us the stock forks, you are pretty much married to a comstar wheel though as fitting a spoke is going to require an entirely new brake setup. If you really want to get crazy, the DOHC guys have figured out how to get cbr600 f2/f3 front wheels and brakes on to their stock fork legs - the same swap applies to you since you share the same forks.

77-78F are not quite tubeless yet (you can run them that way but you are taking your chances). If you want to run tubeless, upgrade to one of the comstars that are tubeless.
 

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Discussion Starter #7
Thanks guys for the info. I really thought originally that I was getting the the latter DOHC bike and thats why I was thinking Freddy Spencer. Early bike looks good and it will get a little of the treatment, but not a DTT type of treatment. I just was looking for outstanding trouble issues and you guys here really know your UJM's.
Thanks again,
Billy

Geeto-I popped over to the DOHC forum and those guys are really getting crazy with wheel and suspension swaps. At least I know I have options. The comstars on this bike are really clean so I will just run them for a bit.
 

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Discussion Starter #8
Thanks guys for the info. I really thought originally that I was getting the the latter DOHC bike and thats why I was thinking Freddy Spencer. Early bike looks good and it will get a little of the treatment, but not a DTT type of treatment. I just was looking for outstanding trouble issues and you guys here really know your UJM's.
Thanks again,
Billy

Geeto-I popped over to the DOHC forum and those guys are really getting crazy with wheel and suspension swaps. At least I know I have options. The comstars on this bike are really clean so I will just run them for a bit.
 

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the biggest improvement you can make to a 77-78F bike is putting it on a diet. Honda really porked it up and there is so much shit you don't need just hanging on it.

Things you can replace to lighten that porker up:

- exhaust: the original pipe setup is heavier than it need to be. it is also rare as hens teeth so when you take it off the bike, put it to the side. A kerker or a mac is worth it just for the weight savings. Used ones are cheap.

- Blinkers and lights: they are the size of traffic stoplights. It isn't the light that is heavy, but in the rear you can ditch the grab rail, taillight, blinkers, plate holder, and plastic rear fender (and smugglers compartment if you want) in one shot. Make a plate that covers the back of the seat tail section and mount your light to that. up front you can ditch the needlessly complicated fork ears for some lighter ones and just sue the blinkers to mount the headlight. whenever going to smaller blinkers I always recommend LEDs as they are brighter (don't forget the ballast resistor).

- chain: 530.

- brakes: not only are the dual piston setups better, they are lighter and smaller.

- seat: that seat is larger than it needs to be. It is comfy though so I can understand if you want to keep it and take off everything else around it. If not, benjie makes a seat that dovetails nicely with the stock breadloaf tank. If not, Bret at GFTP and hot wing glass both make cheap seats but you have to make your own mounts. the seat hinge unbolts from the stock seat so whatever you buy if you salvage your rubbers and hinge and lock, you may be able to make it work like stock.
 

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the biggest improvement you can make to a 77-78F bike is putting it on a diet. Honda really porked it up and there is so much shit you don't need just hanging on it.

Things you can replace to lighten that porker up:

- exhaust: the original pipe setup is heavier than it need to be. it is also rare as hens teeth so when you take it off the bike, put it to the side. A kerker or a mac is worth it just for the weight savings. Used ones are cheap.

- Blinkers and lights: they are the size of traffic stoplights. It isn't the light that is heavy, but in the rear you can ditch the grab rail, taillight, blinkers, plate holder, and plastic rear fender (and smugglers compartment if you want) in one shot. Make a plate that covers the back of the seat tail section and mount your light to that. up front you can ditch the needlessly complicated fork ears for some lighter ones and just sue the blinkers to mount the headlight. whenever going to smaller blinkers I always recommend LEDs as they are brighter (don't forget the ballast resistor).

- chain: 530.

- brakes: not only are the dual piston setups better, they are lighter and smaller.

- seat: that seat is larger than it needs to be. It is comfy though so I can understand if you want to keep it and take off everything else around it. If not, benjie makes a seat that dovetails nicely with the stock breadloaf tank. If not, Bret at GFTP and hot wing glass both make cheap seats but you have to make your own mounts. the seat hinge unbolts from the stock seat so whatever you buy if you salvage your rubbers and hinge and lock, you may be able to make it work like stock.
 

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Discussion Starter #11
Thanks again. It did feel pretty heavy. Sounds like a good laundry list of bits to get rid of. It seems that everything in the late 70's just got bigger and heavier.
Exhaust is mostly shot(rusty muffler) so i will try and find a nice 4-1 for it.
Thanks,
Billy
 

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Discussion Starter #12
Thanks again. It did feel pretty heavy. Sounds like a good laundry list of bits to get rid of. It seems that everything in the late 70's just got bigger and heavier.
Exhaust is mostly shot(rusty muffler) so i will try and find a nice 4-1 for it.
Thanks,
Billy
 
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