Author Topic: 78' carb rebuild  (Read 1122 times)

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Offline jlatkins83

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78' carb rebuild
« on: January 25, 2012, 08:12:18 pm »
Has anyone out there found a place that sells rebuild kits for the 78' kiehin carbs? I cannot seem to find any that exist besides having to by each individual part, which you'd be quite costly. On the other hand if I can't find a kit I am looking at buying a set of carbs from another year, any favorites on what models are the best?
1978 CB750K

Offline ekpent

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Re: 78' carb rebuild
« Reply #1 on: January 25, 2012, 09:03:39 pm »
OK Its late so I will be the first to ask whats wrong with the ones you have now specifically.I have done lets say a few or more old 750's in the past and really have never needed that many new carb parts to be honest,though I have not had any of the newer pumpers 77-78. Basically unless already swapped out for junk or totally abused the brass and metal should still be pretty good if cleaned correctly. Lots of times overflows and 'leaks' are not the fault of the hard parts.   What problem are you having with them for the folks to comment on ?

bollingball

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Re: 78' carb rebuild
« Reply #2 on: January 25, 2012, 09:32:38 pm »
Dig around this place should have what you need.
+1 on ekpent

http://www.siriusconinc.com/search_result.php?make=1&model=cb750&part=1&partno=&search=search&x=27&y=19

                                                      Ken

Offline jlatkins83

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Re: 78' carb rebuild
« Reply #3 on: January 25, 2012, 10:03:43 pm »
As far as I know the carbs have not been rebuilt before, I am the third owner of the bike so some information is lacking. I know that my float bowls tend to stick on me and I leak fuel, sometimes at an alarming rate from my overflow hoses. It also feels a bit sluggish sometimes in its response. Another side note is that the return spring on the throttle cables is really tight and don't like to retract very easily. I need to di into them to check the inner components but worried about not having the o rings and stuff to put it back together. This will also be the first time I've broken down motorcycle carbs and four of them, I have only done work on auto carbs, I assume they are much alike but not sure.
1978 CB750K

Offline Spanner 1

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Re: 78' carb rebuild
« Reply #4 on: January 25, 2012, 10:19:59 pm »
First, don't panic !.... second, you will not need any new carb parts. It's all about cleaning, lots of info here about carb cleaning... do a search, learn, do, enjoy your bike  8)
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline Blitzburgh207

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Re: 78' carb rebuild
« Reply #5 on: January 26, 2012, 08:31:27 am »
Sometimes parts are necessary...that's why they sell them.
I'm in the same boat searching for rebuild kits. I thought I had some saved in favorites but I guess not... I think I had the most luck on ebay to be honest haha.

My carbs have a couple chewed up o rings and I'm missing the little washer on one of the air/fuel adjustments screws.  This is the cause of a few occasional drops of fuel - which I used to live with, but I'm rebuilding the motor and I'll be damned if that tiny little o ring is going to ruin my case paint!   ;D
Anyways - yeah, I think ebay is where I found the most...

Good luck! Let me know if you find anything good!
1978 CB750 K8

Offline Blitzburgh207

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Re: 78' carb rebuild
« Reply #6 on: January 26, 2012, 08:42:27 am »
Dig around this place should have what you need.
+1 on ekpent

http://www.siriusconinc.com/search_result.php?make=1&model=cb750&part=1&partno=&search=search&x=27&y=19

                                                      Ken
Oh wow - that site is great!  Thanks a lot! 8)
1978 CB750 K8

Offline Gonzowerke

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Re: 78' carb rebuild
« Reply #7 on: January 26, 2012, 08:51:11 am »
As far as I know the carbs have not been rebuilt before, I am the third owner of the bike so some information is lacking. I know that my float bowls tend to stick on me and I leak fuel, sometimes at an alarming rate from my overflow hoses. It also feels a bit sluggish sometimes in its response. Another side note is that the return spring on the throttle cables is really tight and don't like to retract very easily. I need to di into them to check the inner components but worried about not having the o rings and stuff to put it back together. This will also be the first time I've broken down motorcycle carbs and four of them, I have only done work on auto carbs, I assume they are much alike but not sure.

As far as the return spring issue goes, I had the same problem on mine, and it was two things causing it. One, the spring on the shaft itself was all gummed up. Spray some carb cleaner on there while twisting the throttle, then spray some light oil(after the cleaner evaporates), like WD40 on there. The other cause was the previous owner messed with the cable tension and the the throttle cables were binding because they were too tight. Look at your cables up by the bars, those silver tube nut looking things are where you adjust tension. Loosen them up, then tighten back until you have just a small amount of throttle grip rotation to your liking. Also, get a cable luber and lube them good! Harbor freight sell a cheap knockoff of the motion-pro one that is more than adequate for the job. I use white lithium spray for my cable lube. Oh, and do the clutch cable while you are at it!

Hope that helps,

Gonzo
1977 F2 "Highway Star"
1977 F2 "Bike-In-A-Box"
1978 K8 "Frankenbike"
1991 CRX Si "Buzz Bomb"
2000 Jeep Wrangler "UBoat"
2011 BMW S1000RR "TIE Fighter"