My 78 CB750F3 Super Sport Project

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My 78 CB750F3 Super Sport Project

Hoko
This post was updated on .

This pic is after I have had the bike for several months now and have done a lot of cleaning and armoralling the plastic stuff (soaked it up like a sponge).  Unfortunately I didn't have a camera when I first bought it so you could see it after it had sat on the PO's driveway for 5 years without being started!  Needless to say it was pretty sad looking!  I was doing some work for the PO and told him he had a great bike (I knew it had potential and I grew up riding hondas in the 60's and they've been my favorites ever since).  He instantly said "You want to buy it?" His wife was definately anti-motorcycle and didnt want him riding it, so I thought about it and said "How much you want for it?"  He said it ran great before he parked it except the charging system had quit and he had all the wiring replaced before he parked it, which was $400 and he would sell it for that.  I said "You got it!"
     Everything is pretty well intact except for quite a bit of rust has set in which I will eventually have to address.  I'm starting with the carburetors which are siezed up as far as throttle and sliders.  I want to get it running so I can check the cylinder compression to see what kind of shape the engine is in.  I finally am getting some time to work on it so I will post as I work through it.

The throttle bar is completely siezed up and the sliders in the back of the throat are frozen as well.

The boots on the airbox were loose when I took it off and one of them was torn so those will get replaced.  The boots from carb to engine were stiff and clamps were worn also so I'm replacing all of them so the whole system will be well sealed.

I made a tank with plexiglass and silicone to soak the carbs in about the size of the carbs so I wouldn't have to buy any more of that Chem-Dip ($30/gal!) than I have to!  I should have some time this week to pull all the rubber and gaskets out so I can dip it for a week.---UPDATE--- About 10 minutes after I put the Chem-Dip in the tank with the carbs, it started leaking.  The plexiglass is fine but the Chem-Dip is destabilizing the silicone caulk and it is causing it to let loose of the plexiglass.  So I went to Target and found a plastic container that looks like it will work.
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

pat english
dang thats beat bro!..jk..pretty good shape for what you paid for it...if youre intake boots are not cracked,you might wana consider doing that carb boot restoring trick.those boots are $90 brand new..i forget what the proceses is(someone will chime in on exactly how to do it),but i hear its makes them soft and flexible like new and works fast..i personally just soak them in oil for a month or so...ask tools if it works,i just sent him a set of intake boots that i had soaking for a while.

thats a pretty sweet box you made,but if you lay the carbs down you will be able completely submerge the carbs with 1 gallon of dip..

also,didnt i send you a seat?youre seat looks a hell of a lot better then the one i sent..i feel bad now. if you need anything else,and i have it,you got it.
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Re: My 78 CB750F Super Sport Project

LukeM
Administrator
Wintergreen oil in water.  TOOLS will remember the ratio, but it works well.
My son's carb boots were cracked on the inside, and I was thinking of lining the inside with a very thin layer of RTV silicone.  Then again, I wouldn't want any of that flaking off and getting in the engine.  Might work OK on the outside.  

Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.
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Re: My 78 CB750F Super Sport Project

Hoko
This post was updated on .
lol, if you saw the seat up close you can see it is cracked bad, wouldnt even last a month before it starts to shred, I just sprayed some armorall on it for the shine so I wouldnt have to look at it while working on it, not to mention the cleats that hold the seat cover on the bottom of the seat were rusted off on one side.  yeah maybe I'll be able to lay the carburetors down after taking float bowls off.  good idea Thx for the tips for softening the boots!  Probably wouldn't hurt to take those boots off every 2-3 years and soften them up.
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

pat english
In reply to this post by LukeM
hey,i used some of that plastic weld 2 part epoxy on the intake boot of the cm 250..it was cracked..now its all good..
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Re: My 78 CB750F Super Sport Project

pat english
In reply to this post by Hoko
oh right on..well still,you need anything,let me know..

2-3 years?those dam boots last 30 years!..i think if you softin them up again,theyll probly outlive you.
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Re: My 78 CB750F Super Sport Project

Hoko
When I took the air box off the carbs yesterday I wondered why they fit the carbs so loose.  Today I was looking through the FSM and I realized they were so loose because the PO was running it with no clamps on the boots!
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

pat english
thats strange..you need those clamps!
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Re: My 78 CB750F Super Sport Project

Hoko
Yeah, that would explain why the air filter was so clean
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

Hoko
This post was updated on .
These little fellers were pretty gunked up.



One of them didn't have the varnish in it but had rust in it like it must have had water in it.



See the Float Needle Seat?  How do I remove that and install a new one?  I'm thinking this one is not removable, it is round and flush with the carburetor casting like it was pressed in.



It may not be a small container but its the closest size I could find to the carbs. (used 2+ gallons dip)  I'm just glad to get the ball rolling.  Gonna leave them in there till next Monday. Now I just need to find some carb kits.
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

pat english
hey looking good bro...tools will know how to get those jets out...he seems to know everything..

take those carbs out after 2 days or so and try to get things to move..my stuck throttle valves came out 1 at a time.
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Re: My 78 CB750F Super Sport Project

Hoko
This post was updated on .
Ok Pat, THX!  Ordered carb kits, should be here before carbs are done soaking  Think I'll just slap some pipe clamps on those airbox boots and replace the boots later.  I was thinking I would replace the float needle seats but these are round not like those replaceable hex jets and look like they were pressed into the casting since they are flush with the carb casting.
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

Hoko
I saw a carburetor assembly like mine for sale on this site http://www.motorcyclecarbs.com/CARBURETOR_KIT_HONDA_CB750F_K_P9270C646.cfm      I clicked on buy just to see how much they wanted for it      WO! $800  
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

shinyribs
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LOL> I have seen some crazy prices for parts on these bikes. Some guys are nuts. Are you sure you need to replace those seats? If they are smooth and dont have gouges or a wear ring in them they might be OK. Good luck with your carbs Batman
A free people ought not only be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.~George Washington



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Re: My 78 CB750F Super Sport Project

pat english
In reply to this post by Hoko
those look like the cr carbs.
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Re: My 78 CB750F Super Sport Project

Piute
pat english wrote
those look like the cr carbs.

   I think there stk. carbs Pat, look same as mine.
But what the hell I'm just bargaining to fine tune mine,
  Miles N miles in between tune-ups
                            1977 CB750 F2 Super Sport
<LET THOSE WHO RIDE DECIDE><RIDE TO LIVE-LIVE FOR JESUS> 
Native American from central Cal,  Kickstand UP in S.W.Missouri,
                                       
 
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Re: My 78 CB750F Super Sport Project

Hoko
This post was updated on .
In reply to this post by shinyribs
shinyribs wrote
LOL> I have seen some crazy prices for parts on these bikes. Some guys are nuts. Are you sure you need to replace those seats? If they are smooth and dont have gouges or a wear ring in them they might be OK. Good luck with your carbs Batman
You know, I am just a noob and will do anything someone says I should do, haha so I guess I should just put it together and see how it runs!  Anyway I am learning as I go and it really is a lot of fun since I like gearhead stuff.  That Batman stuff gives me an idea.  That would be downright bodacious to make a batcycle like the one in "Batman Begins", that was one awesome bike.

What do you say, We team up and build this bike!








78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

Hoko
This post was updated on .

" Check your connectors:  if you used crimped wire connectors, try soldering them, as crimps can fail, easily."   Sarge

That would not be good if that happened here.  Is there any way to organize this pile of spagetti?
78 CB750F3 Super Sport
Austin, TX
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Re: My 78 CB750F Super Sport Project

pat english
it did happen there...you got alot of wires added into that mess..someone has fucked with youre harness..might be a good idea to just buy a new one.i think theyre around $100..well worth the piece of mind knowing youre bikes not guna burn down.
wes
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Re: My 78 CB750F Super Sport Project

wes
that wire mess looks alot like mine. i had to look for fuse panel. i found it behind headlight in box. pat, you say you can get a new harness for around $100? where might that harness be? it would be nice to have a new one, im on a shoe string budget these days. every thing on the bike works, im wonderin if i should just leave it as is. maybe i should get brakes workin right first... so much to do... so lil cash.
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