[fuzzybutt]

about a month or so ago i picked up a 75 750f from my physical therapist for a couple of hundred bucks. i'm wondering, what are the main differences motor wise? i've been told a few different things, big valves, bigger cam, more compression? it's all there and all original, not sure whether to restore it, chop it or cafe this one too. i havent really given it a good once over yet

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs

Edited by - fuzzybutt on Apr 17 2007 8:34:30 PM

 

[Geeto67]

75 motor has a different cam and a little more compression, but it is not the big valve head that the 77-78 bikes had (sorry to dissapoint). Personally the F bikes (despite being one of my favorites) are pigs and the more you can do to lighten them up the better (leaning toward cafe here). just out of curosity, what color is it? some colors are rarer than others and should be saved. If it is flake sunrise (orange), sulfur yellow, or Blue you should try to save the paint. Candy Anteries red was pretty common on 76 models so if you scrap the paint no big loss. The biggest thing I like about the F's over my K bike is the disc brake rear, although it needs to be drilled to be a true all weather bike.

 

[fuzzybutt]

it was blue once upon a time but it's too far gone to save, i tried to hand rub it a little today with no luck
buffer just killed the finish entirely.

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs

 

[LiLBull]

well if your H E R E ! smirks Id say cafe ,but thats just me.Looks like with your recent back promblems id keep the handle bars at a comfortable height till you truely heal and do everything else in the cafe spirit.

Im so far behind ,that I think Im in first.

 

[Geeto67]

I always forget where to find the differences between the model years, here is the actual differences for the 75-76 F1 supersports:

new camshaft, carbs w/additional idle air. New pistons, compression ratio 9.2/1. New case w/o primary chain oiler. Final drive gear ratio 43/50 i/o 48/50. 4th gear on main shaft 31 i/o 30, 5th gear on countershaft 31 i/o 32.


Candy sapphire blue is a rare color for F's, Mostly because candy finishes don't seem to hold up well over time. If it is shot then you have nothing holding you back - cafe that bitch.

You can't use the 836 kits out there now because of the pistons and increased compression, but right away you are ahead of a stock k-bike. Some of the guys at SOHC have expiremented with the 77-78 carbs and found that they work better than the earlier carbs(they are just a pain in the ass to rebuild) because of the redesigned accelerator pump. K&N makes a filter that fits in the stock airbox.

Anything you can do to shed weight on these pigs is the best thing for it. That taillight/grabrail assembly is just a nightmare of heavy metal. The seats (as pretty as they are) are not light either. a bumstop fibreglass seat (like those from 1hotwing on ebay) and light weight taillight and signals frees up like 10-15 lbs. Don;t buy fibergalss seats made to work with cb750 seat hinges, the F models have a different seat hinge that actually unbolts and can be used with any seat. The F has the tank modeled after endurance racers of the era so it is a great starting point.

Clubmans are espically a pain in the ass on this bike because of the gauges and the master cylinder (the M/c hit the gauges) so go clipons right away and save the aggrivation. Raask and tarozzi both make specific rearsets for this bike, but you can use the passenger peg holes and make your own as well.

The exhaust is a heavy contraption on these bikes and really isn't worth the hassle of keeping if you are cutting it up. A Kerker is the best right now for the bike, lighter and more power but hella expensive. Macs are just lighter and you need to repaint them before you use them to keep them from rusting.

keep us posted on what you do.

 

[fuzzybutt]

well, this one os getting cafed and the 74 750k is getting a hardtail welded on and getting chopped since it'd be silly for me to have 2 cb750 cafe racers. when i tear the 750f down i'll tank the head and do some port work on the head, adjustable cam sprocket like on all the 750's i've done, i'll make the buttstop seat thats on the 750k now work with the 750f, i got the seat from retromototoys on e-blow. i have a set of rearsets i've been meaning to put on the k bike but now i'll fab some brackets and use em on the f bike as well. i'll also put the kerker header thats on the k bike onto the f and i'm going to fab some drag pipes for the chopper. all this just as soon as i can get rid of this damned aspen collar they neurosurgeon has me wearing.

 

[Geeto67]

why not just keep the 74 cafe and chop the F?

 

[LiLBull]

why not cafe them both,its not silly its COOL to have two or more cafe bikes.
Remember to Geeto stripping wieght off a 750 anything K,F or CR is important and not under the guise of "cafe".Geeto is a big guy so if your jocky size the 750 is a strong bike stock.

Im so far behind ,that I think Im in first.

 

[fuzzybutt]

lol i'm the size of 3 jockeys at 340 or so.

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs

 

[fuzzybutt]

it's been decided after i was given a rolling chassis from cycle exchange by a bud. the 74' 750k is gonna get chopped and the 750f is getting cafe'd. the motor is coming out and apart to get an 836 kit and better rods, head is getting ported and a better cam installed. as much weight as is safely possible to take off will be taken off and i have some rask rearsets i was going to use on the k bike that i'll adapt for the f. cant wait to get out of this damned aspen collar and off the pain meds so i can function. i wanna cut, chop and weld!

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs

 

[Geeto67]

I still don't get why you are undoing one bike just to do it all over again on another. Seems like a lot of work to me where as you can just use the F stuff in the chopper.

 

[fuzzybutt]

the frame on the k bike has been repaired in a few spots. i'd rather do a cafe with a good, unrepaired frame and lose the cracked/repaired one. the k frame will PROBABLY be ok but why chance it.

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs

 

[Geeto67]

a very good point.