Author Topic: Carb issues...are these rebuildable?  (Read 1532 times)

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Offline phaedrus314

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Carb issues...are these rebuildable?
« on: October 23, 2011, 08:13:07 AM »
I purchased a non-running 1973 CB500 with 6k miles that "ran when it was put up 3 years ago" but he wasn't able to get it running.  The carbs were in place but disconnected and the drain plugs point the wrong direction so have obviously been mucked with.

Long story short I pulled the bowls and found this:



Offline phaedrus314

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Re: Carb issues...are these rebuildable?
« Reply #1 on: October 23, 2011, 08:21:53 AM »
The main jets were installed in a manner that cut the o-rings against what appears to be a ridge of corrosion around the edge of the jet tower.  Can I soda blast them, file the sharp edges (do they have a lip to retain the jet?)

They also have little or no gas smell and are pretty varnish free so i assume they have been dipped in something. 

3 of the overflow tubes in the bows have blobs of solder on them so I assume they are cracked as well. 

Basically I want to know if these are beyond hope due to pitting and corrosion or if they are worth a kit, install and test...should i reuse jets or do a full kit...etc.

I know the pics are not the best but if others of specific areas would be helpful, let me know.

Offline Rigid

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Re: Carb issues...are these rebuildable?
« Reply #2 on: October 23, 2011, 09:02:39 AM »
Carbs can be reused and repaired even when they are in the condition you show.  The soda blast will remove the oxidation and your careful attention to detail will disclose any pits that have gone all the way through the metal.  Even then, a pit can be filled successfully with gas tank Kreem coating.  The jets are retained by the clip that rests against the bowl.  Use your judgement, and research this forum for repair ideas.  Some reapairs, like JB weld, just won't stand the test of time and fuel soaking.  Some others, like solder, will last decades. 
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Offline phaedrus314

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Re: Carb issues...are these rebuildable?
« Reply #3 on: October 23, 2011, 10:40:31 AM »
I don't think any of the pits are through the metal, i was more concerned with the potential porosity of the metal.  I am going from memory but I don't remember there being a clip that retained the main jet, just the leaf spring...is that what it's there for?  There is a clip that retains the needle valve and seat though.

So if the opening to the main jet mounting tube needs to be filed straight that's not going to be an issue? 



Offline Rigid

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Re: Carb issues...are these rebuildable?
« Reply #4 on: October 23, 2011, 11:14:34 AM »
Yes, the clip secures the main jet in those.  I don't see a problem smoothing that ridge if it will help the seal to not be damaged.  I just don't remember an edge in there that would cause a problem.  Maybe someone else will respond that remembers the details.
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Offline phaedrus314

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Re: Carb issues...are these rebuildable?
« Reply #5 on: October 23, 2011, 01:51:44 PM »
All of the main jet orings were torn when the jets were stuffed into the mount location.  The ridge I see is possibly corrosion or damage from sloppy installation though I have no idea how you could ever apply enough pressure to do that.

The part of the jet that protrudes was also pretty torn up.

Btw thanks for the help.

Offline Rigid

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Re: Carb issues...are these rebuildable?
« Reply #6 on: October 23, 2011, 03:02:50 PM »
I am always glad to help.  Not everybody grew up wrenching, has a degree in mechanics, or had a dad around to show them things.  Now ask me about skinning muskrats and fox trapping and I have some real inside knowledge and expertise! 
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Offline phaedrus314

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Re: Carb issues...are these rebuildable?
« Reply #7 on: October 23, 2011, 03:32:39 PM »
Ok so for the next question...which carb kits should I get?  Should I trust the oe jets and just do orings n gaskets or start over with jets etc...and which brands are recommended?

Offline Danno

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Re: Carb issues...are these rebuildable?
« Reply #8 on: October 23, 2011, 03:33:21 PM »
the edge can be relieved with a counter bore by hand and gently
those are not the worst carbs I have seen by far I would dip them three times , a lemon juice dip , a simple green dip , and a evapo rust dip after you remove all the rubber seals , after that soda blast them and they will look nearly new
when you own a motorcycle the wife does not have to find you handy she just has to find you

Offline MoMo

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Re: Carb issues...are these rebuildable?
« Reply #9 on: October 23, 2011, 05:44:42 PM »
Ok so for the next question...which carb kits should I get?  Should I trust the oe jets and just do orings n gaskets or start over with jets etc...and which brands are recommended?


I never replace jets and I've resurrected almost 30 bikes in the past .  As long as the stock ones are clean I prefer that over any aftermarket.  You will find quite a few threads on here with reference to poor quality aftermarket jets.  If you can buy Honda gaskets, but I have had good luck with aftermarket gaskets that have been supplied to me...Larry

Offline Rigid

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Re: Carb issues...are these rebuildable?
« Reply #10 on: October 23, 2011, 05:50:06 PM »
Ok so for the next question...which carb kits should I get?  Should I trust the oe jets and just do orings n gaskets or start over with jets etc...and which brands are recommended?


I never replace jets and I've resurrected almost 30 bikes in the past .  As long as the stock ones are clean I prefer that over any aftermarket.  You will find quite a few threads on here with reference to poor quality aftermarket jets.  If you can buy Honda gaskets, but I have had good luck with aftermarket gaskets that have been supplied to me...Larry

+1, thanks Larry.
36 years of this stuff, here to help.