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Author Topic: 1977 CB400F Super Sport "Give Up"  (Read 20489 times)

Offline PHeller

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1977 CB400F Super Sport "Give Up"
« on: Aug 23, 2010, 23:18:59 »
Just picked this up. Almost all original parts, but not the original exhaust  :(  - I vow to finish this bike with a sweeping 4-1 exhaust.

I got a spare tank, footpegs, lights, etc.

Currently, the bike doesn't idle or go faster than 15mph.

PREVIOUS OWNER REPLACED OR SERVICED OR FUCTED UP: Fork seals, valve springs?, K&N pods, MAC 4-1 Exhaust, mini rear light, superbike bars, cleaned and rebuilt carbs with below mentioned "mods", replaced key cylinder, reupholstered seat (nicely), new (crappy) throttle and clutch cables (that are crappy).

CARBS: Previous owner drilled "one size up" on a set of drill bits. I have no idea what that means. Needless to say I think the stock jets are kafucted. I'll replace with a set of #85, as I've read that is what is necessary for pod filters alone.

EXHAUST: Previous owner scrapped the original exhaust this past week, deeming it "too beat up to keep"....I disagreed...but the current exhaust is a MAC piece in ceramic coat black. It's not overly loud, so I can't see it changing the flow (or jetting) that much. Hell, it might flow WORSE than stock. Disappointed about this one.

ELECTRICS: Everything works...strangely enough...but the wiring is a rat's nest of wire nuts and electrical tape. Random wires are cut places, and others groups of wires are all connected together. The starter wire is all on its own...running around the bike like someone lost track of the original wire and decided to run their own.

I got all of this for a few hundred bucks.

My inspiration?

Woody's CL350


I'm thinking low, sleek, and built for style, not for speed. I might actually get ahold of a CL360 front wheel with drum, and a few other "back dated" parts.
« Last Edit: Aug 24, 2010, 16:19:46 by PHeller »

Offline Kanticoy

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Post a pic of her up. I have always wanted to see what a MAC setup looked like. It actually has a better collecter on the pipes than stock so i imagine it would be a good candidate for a race exhaust depending on the can....just curious what they look like. I'll help any way I can. Put her as close to stock as possible and go from there first....especially on the carbs.
I get not knowing, but I can't for the life of me understand not trying. It's only metal it can be fixed. Man up and risk a mistake in exchange for a lesson.
'

Offline PHeller

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Well I can't go too stock because of limiting funds.

The condition of the stock air box rubbers is such that I'm tempted to stick with the pods. You may disagree. I'll post pics of the box.

Replacing the exhaust would be a mad expensive proposition, so I'll re-jet according to a better flowing exhaust. Maybe a 90 main? No idea on the low speed jet.

Electrics really worry me. I'll post some pics of that mess, because I'll really need some help there. The funny thing is, as hacked up as the wiring is, the bike still runs.

I rode it down the street and back, shifted all gears, clutch worked, brakes worked...all just very slowly.

Offline Kanticoy

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Oh no, I didn't mean make the bike back to stock, I meant put the jetting back to stock.  I run velocity stacks on my 400f with a MC Again header, and I upped one jet size for the pipes, one for the velos.  I just mean, get rid of the shoddy jets and put good ones in.  Rule of thumb is one size for pods, one for exhaust....gets you pretty close to ball park.  Do a plug read and see how they're looking...my guess is fouled.  And the floats in these little guys LOVE to stick and puke fuel.  Get you some anti seize from the auto parts store and put it on the float pin when your putting your jets in.  It really helps.
I get not knowing, but I can't for the life of me understand not trying. It's only metal it can be fixed. Man up and risk a mistake in exchange for a lesson.
'

Offline PHeller

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What jets are you running? #85? or 90? Stock is 75 I believe.

What about the idle jets? Up or down or no change?

Any pics of yours, Kanti?

Offline Big Rich

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As far as the wiring harness goes: if it's just TOO bad, im sure you could get one from a similar bike and just compare the wiring diagrams for each. They should be almost the exact same (just guessing)

Offline PHeller

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Re: 1977 CB400F Super Sport "Give Up"
« Reply #6 on: Aug 24, 2010, 22:24:13 »
Clutch actuator lever is messed up. Clutch is also very stiff. One broken bolt/stud and the other is missing.

What lies under the tank.

Wiring mess.

Lots of work needed.




I tried starting it again tonight. After about 20 kicks it lit up, but would only run under 1/2 throttle or more. Won't rev more than 2,000 rpm, no matter how much throttle.

Won't idle.

Plugs are wet.

I tried timing it as best as I could, but I don't have a timing light so I have no idea on how close that is.

Didn't check the advancing unit, that's tomorrows project. After that, its onto the carbs.

Offline teazer

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Re: 1977 CB400F Super Sport "Give Up"
« Reply #7 on: Aug 25, 2010, 01:03:37 »
That's not a bad start.  The wiring may look like it's guts are hanging out like it committed hari kari, but really I's just untidy. That should be easy to tidy up.

Seat is a good place to start but it needs some sort of rear fender.  The symptoms sound like jets clogged in the carbs, but we don't know how good the motor is or how old the plugs are. Start with giving a good clean and service it.  Clean the carbs, fit good new plugs, check for a fat spark from both coils check compression while the plugs are oput and set the tappets.


Offline PHeller

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Re: 1977 CB400F Super Sport "Give Up"
« Reply #8 on: Aug 26, 2010, 22:12:52 »
Ok, so I got the carbs off tonight, which was pretty easy, and I was disappointed at what I found.

The bowls must have been leaking on the previous owner, so he used some sort of sealant to seal them...only it didn't harden and turned to a gooey mess inside my bowls.

So here's the run down:

External Condition: Good, most screws come loose pretty easily. Everything seems to be there including hoses. Discovered PO must have switched the throttle because it only had one cable. There is no return cable on the carb.



Bowls: Gunky with gook. Drain screws were extremely tight (probably because of gunk), and one I couldn't get out...I actually rounded a flathead screw...


Main Jets: Marred and gouged, clogged and two had really messed up seals. They don't appear to be drilled, but who knows.

Pilots: clogged, but otherwise fine.

Carb body (inside bowl): I'm seeing some pitting on the #4 jet holder thing. Is this a problem?


Floats: Here is where I noticed a big question. The float has a nick in it. Are these solid floats? Does this nick keep it from floating?


Throats and slides: Both look good. Some little nicks on the slides, but nothing serious...I think.









Offline BigBSBusa

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Re: 1977 CB400F Super Sport "Give Up"
« Reply #9 on: Aug 26, 2010, 23:53:27 »
Comin' together.  Carbs are always a tough thing.
BigBS

1974 Honda CB550
1977 Yamaha XS750 - Project Maggie Mae
1994 Kawasaki Ninja ZX11 - Project Raven
1999 Suzuki TL1000R - Project Sable