Topic: 750k0 Aftermarket carbs

[martini]

Great Guys, thanks for the info. I think I know where I stand now. My throttle assembly does not have provision for a second cable, so I guess I have three options:

1. Try and find a set of carbs off a K0;
2. Get a later model set and make use of a single cable;
3. Get a later model set as well as a later model throttle assembly.

Food for thought. Thanks again for the help.

[kghost]

Martini,

The option of using the later housing on the grip would be best.

You'll need just the bottom part of the housing. You will have to swap the starter wire over but its alot easier than running all the wires thru the bars. The bottom housing should fit on your upper.

[eldar]

You should be able to get parts for your current carbs as well. If there is no physical damage to the bodies and all you need is new jets and needles, just get the parts.

Bob it is funny that you say we will hurt your carbs feeling! I bet you sounded like a drunken sailor while working on them!

[Bob Wessner]

How about a drunken, cussing sailor. 

[eldar]

isnt that redundant?

[Bob Wessner]

True, but then so are FOUR cables. 

[eldar]

you dont hear me denying that! 4 carbs are redundant...no those are just a pain!

[retrogrrl]

No one has a recommendation for aftermarket carbs?  I have went through 2 full sets for my bike (78 550k) and some misc. parts and it still ran crappy... and getting new/old ones off ebay doesn't guarantee anything.. they come just as dirty as the last ones in my experience... so if i REALLY wnated something aftermarket... is there an option?

[martini]

Retrogirl,

Check out www.sudco.com. They apparently have carbs that will work on the old CBs. They are pricey - I looked into it quite some time ago so I can't recall exactly but something like $800 (thats Canadian, so 50 cents American!). What I did was send them an e-mail with details on my bike and they told me which carbs they reccomended.

If you do get some let me know how they work out, I'd be curious.

Martini

[techy5025]

My K0 is running with a set of carbs from a later year 750.  I am not sure of the
year because I was not smart enough to check the bike I took them from...in
a motorcycle junkyard.  They seem to work fine.  I am using only one cable, the
pull cable, as I have the original grip that allows for only one cable.

The original four into one throttle pull was a royal pain,  because small shifts in
the four part of the cable make for big differences in carb balance.  And as I recall
there was no anchoring method on the cable so even moving the handlebar back
and forth caused the cable to shift....expecially whee it bends 90 degrees to go
into the top of each carb.....really bad design..

The original carbs are tucked away in a box.....with holes in the floats.  I would be
surprised if all the original brass floats don't eventurally develop holes.  That's probably
why Honda replaced them with plastic. If you decide to keep the original carbs at least
replace the floats with new ones....tiny holes in the brass ones can be hard to detect
until they fill up with gas and sink to the bottom on the bowl

I think I paid 50 bucks for the full rack of later carbs a couple of  years ago at the
junkyard.  They were physically OK but needed severe cleaning.  I guess now their
availability on Ebay has driven the price up though.

I use a carbtune to set them up.  Great gadget....but a little pricey.  Sorta like a chain
saw...when you need it you really do....other times its an expensive shelf decoration.

Good luck and enjoy your new toy.

Jim

[T140 kidd]

 I've got 74 carbs on my 78 k (bigger vinturi's flow more air, in theory). I got rebuild kits (1 per carb) from K&L, had Everything but float's. Tweaked the brass ones back into shape and all okay in the land of carb's. Kit's came from Parts unlimited  vender part number 18-2421. Cant tell you if still available
but they had kits for all cb750's in cataloge at the time. But did not offer kit's for 77 and 78's. I've been told that only Honda has kits for 77-78's and they are about
125.00 a clyinder. Dont know if that's true, I'm just glad I did conversion to earlier
style in the 80's.
 BTW you picked a Damm good bike for a learner. Get a Haynes book and dont be afraid.

 "Keep youre knees in the breeze and the Supostas in youre mirrors"
      Art

[martini]

I'm in the exactly the same boat as you techy - running a later model carb, year unknown, on my K0, using only the pull cable. Any safety concerns using only the one cable?

[MRieck]

Retrogirl,

Check out www.sudco.com. They apparently have carbs that will work on the old CBs. They are pricey - I looked into it quite some time ago so I can't recall exactly but something like $800 (thats Canadian, so 50 cents American!). What I did was send them an e-mail with details on my bike and they told me which carbs they reccomended.

If you do get some let me know how they work out, I'd be curious.

Martini

I have used both the CR-29's and 31's.

[techy5025]

No...Martini....maybe ignorance is bless.  Actually after looking at the
thickness of that return spring, I would be more concerned with the
the pull cable jamming in the sleave ...insert lots of lube.

Still wish I had bid on the K0 that was on Ebay last week.   Mine needs
a twin.

Jim

[techy5025]

BTW Martini....I don't know if this is your first SOHC or not, but
be prepared to spend lots of time with bike admirers.

I rode down to the Honda automotive dealer last week for a car
part.  It took ten minutes to get the part and an hour to get back
on the road. Lots of people like these old bikes.....had one,  wanted
one, regret selling one. etc.

I guess they really stand out from the Harleys and crotch rockets.

Jim

[jaannaktin]

my two cents ... 

sorry to pick up the thread late -- I have an early model K0 with the four-into-one throttle-carb assembly. I actually like the primitive aspect of the throttle-pull-open, spring-pull-back mechanism. It is subject to a lot of positional BS, but it is unusual to push or pull handlebars to that degree, at least while the clutch is not engaged.

I have ordered a few replacement parts, mostly from western hills honda, they always seem to be able to get what I need. My carbs are mostly intact, and I have only replaced the gaskets and o-rings (and the throttle cable). I have been thinking about replacing the needle jets and the jet needles since I seem to run rich, but that is a topic well covered in other threads ... like Bob noted, I seem to have some mutt parts mixed in, and I can't guarantee that all that I see when the carbs are disassembled are stock parts.

I have seen several sets come and go on ebay - I don't think orphaned carbs are that rare. A complete overhaul may be expensive (if you have to find needles, jets, floats, etc), but judging by this thread it doesn't sound like there are simple options for replacement.

I have rebulit my carbs three times in the last six months, which propels me from rank amateur to green newbie to bloody-knuckled grinner! The most important thing is ... have fun!

[Bob Wessner]

I have only replaced the gaskets and o-rings

jaan,

Just curious, you talking about the o-rings on the fuel Tees?

[jaannaktin]

Bob:

Yes, I meant the t-piece o-rings. I had tried to salvage the gaskets and o-rings that came with the machine; the bowl gaskets were fairly rotten but held up -- the t-piece o-rings crumbled and the temporary o's I used from the local hardware store (plumbing grade) practically melted after a few weeks, creating a nasty leak. Hence the reason for rebuild number two ... gasket and o-ring replacement.

Still learning the ways of the carb force, my master.

P.S. Just checked ebay -  bidding now = 4605977298   225 bucks all parts there "sandcast" carbs - makes me want to part out my bike!

[dusterdude]

i sure wish someone would try out the cycle exchange twin mikuni setup.

[Bob Wessner]

makes me want to part out my bike!

I know the feeling.  Just think, sell it off one screw/bolt at a time and advertise them all as "sandcast." 

[martini]

"BTW Martini....I don't know if this is your first SOHC or not, but
be prepared to spend lots of time with bike admirers.

I rode down to the Honda automotive dealer last week for a car
part.  It took ten minutes to get the part and an hour to get back
on the road. Lots of people like these old bikes.....had one,  wanted
one, regret selling one. etc.

I guess they really stand out from the Harleys and crotch rockets."


Yeah Techy - it is my first SOHC and I know exactly what you mean. There is a spot just outside of town here where you'll easily find 200-300 bikers gathered on a nice weekend. Took the K0  out there last summer and she was the star of the show. Everbody's got a story about the first time they saw one, the one they used to have, the one they used to want, the one there uncles brothers cousin used to own etc, etc. Its good fun. The only bike I've seen get so much attention is my buddies Royal Enfield. The thing is a 1996 but it looks like something out of the 40's. It always gathers a crowd.