new guy with a prob..please help!!

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new guy with a prob..please help!!

desmond
Whats going on everybody? I took a project 81 cb750k bobber on trade a while back that was in pretty rough shape. I have finally got it to the point of trying to start it but I'm not getting any fuel. I have never messed with a older Japanese bike before and it has what u guys call SOS (spawn of satin). I have looked around on here and can't find any post with the same prob I got so I need to see if one of u honda gurus can help me. I get fuel down to the SOS but nothing out of it to the carbs.  I saw some ppl bypass it but when I did it flooded the bowls and I had gas coming out everywhere. Can someone please point me in the right direction! !?? I really don't want to give on on it but I'm ready to throw a match in the leaking fuel!!
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Re: new guy with a prob..please help!!

hondacb750f
Don't throw a match to it . there is plenty of help here first things first welcome to the board. how familiar are you with carbs. And do u have a manual? they have free ones here on the site. just llok up your bike.

Second. what type of carbs do u have?   Have you taken them apart to clean them.
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Re: new guy with a prob..please help!!

TOOLS1
Administrator
In reply to this post by desmond
The "SOS" would not have any thing to do with fuel coming out of your carbs. That problem would be the floats, or needle valves not seating. The SOS just turns on the fuel when the engine is running, and creating vacuum. They are unreliable when they are 40 +/- years old, and it is common to disconnect them. However you still need to go back and address the floats, and needle valves.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: new guy with a prob..please help!!

hondacb750f
In reply to this post by desmond
And with out telling every one what you did as far as test go. we can only assume you are not getting fuel.  so with that being said, we have the same carbs and body style.  You should be able to open the top of the carbs and looking towards the front of the motor thru the carbs. Do you see them open? while twisting throttle?


If you do then fuel is not the issue.  These bikes are NOTORIS  for carbs being 90% of the problems. Please post a video and or pictures or your bike,  I bought a 81 cb 750f super sport close to three years a go.  ANd with the help of several people here. I am only a couple weeks away from being road ready, It took me so long because I work 2 and some time three jobs.  Be calm these bikes are worth it.

WE need to know  mileage, carb style, what you have done. what the previous owner has done, and any thing else you think we may need to know.


If evey one will allow I would like to take this man and his bike on as a project.  To show what I have learnt from here.

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Re: new guy with a prob..please help!!

desmond
In reply to this post by TOOLS1
Thanks guys. I have taken them apart to clean them as I have no idea how long or the conditions of where it was stored and I already figured I was gonna have to get a "rebuild" kit for them the floats appear to b in good shape. I didn't know if the sos "regulated" the fuel to the carbs or what and y I cant get fuel past it to the carbs.  The diaphram in it appears to b ok as well.
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Re: new guy with a prob..please help!!

desmond
In reply to this post by hondacb750f
The po completely stripped the bike down not turn signals, horn, Speedo not even a front break.  The wiring was a mess and hacked up so I had to completely rewire the bike. When I twist the throttle the butterfly s open . I can spray a bit of fuel in the carbs and the bike will fire right up but just for a second.  Ill try and post what pics I have on my phone
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Re: new guy with a prob..please help!!

motogrady
Hey Desmond, you're doing great.  Rewiring everything, getting to where it starts on spraycan,
very big deal.

I suggest just gut that petcock.
Take a drill, an ice pick, whatever, just hack the internals out of it, including the screen.
Get a clear, inline plastic inline fuel filter and put in maybe half way in the fuel line.
Lowes has them for lawnmowers, they cost 9 dollars.

When you get fuel flowing to the carb rack, tap the carbs gently to help them seal the float valves.
If one or more leak, just take 'em apart and get the crap out that's keeping the valve from seating.
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Re: new guy with a prob..please help!!

desmond
Lol thanks motogrady but when I say comletely rewire I mean I just started from scratch with all new wires and just wired what it needs to run and b leagal which in my state is headlight and tail light lol tho I can follow a schematic pretty well. The bike has been hardtailed so there really is no going back to stock shy of buying a new frame
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Re: new guy with a prob..please help!!

desmond
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Re: new guy with a prob..please help!!

desmond
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Re: new guy with a prob..please help!!

motogrady
In reply to this post by desmond

hey man, you gotta flip that thing rightside up or the fuel will never flow to the carbs.














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Re: new guy with a prob..please help!!

desmond
Damn it I knew it was something stupid lol. Cant figure how to flip them from my phone
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Re: new guy with a prob..please help!!

TOOLS1
Administrator
I see you are in Australia.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: new guy with a prob..please help!!

shinyribs
Administrator
I had to flip the pics because I really wanted to see them.

Bike looks great man. How are you liking it? As far as ride and all.


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Re: new guy with a prob..please help!!

Truck
Nice bike, bet its LOUD with those pipes on it!
It's only illegal if you get caught.

If at first you don't succeed, use more lighter fluid

95% of Harley Davidsons ever made are still on the road... The other 5% made it home.

New Baltimore, Va '82 CB900c, 1980 CB985F/K 'Mutt"
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Re: new guy with a prob..please help!!

desmond
Thanks guys I love the looks of the bike I haven't really got to ride it yet due to the fact I really don't have it running yet but the few times I have started it was Extremely loud. I started it in the garage one day and my wife said it scared the shit out of the kids lol oops
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Re: new guy with a prob..please help!!

TOOLS1
Administrator
Bikes like that. are supposed to scare kids, old people, women....
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: new guy with a prob..please help!!

hondacb750f
Desmond.

  Grert looking bike. Good deal on your part.  Truth be told  with you running  wire you are already a head of me.  I will sit back and see what I can learn?  I do have a couple questions,

what size are your jets?

Have you check the plugs to see if they are wet?

Did you synch the carbs?  

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Re: new guy with a prob..please help!!

hondacb750f
also how smooth does the choke move?
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Re: new guy with a prob..please help!!

desmond
Thanks brother.  As far as the jets im assume they r stock can't remember off the top of my head and as far as syncing them I haven't got the bike running to do that yet.
I was wondering if from where the po removed the air box that I do not have and have yet to order any filters if maybe its not creating enough vacuum to make it past the vacuum pump?
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