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Broken carbs

  • BertClicteur
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04 Jun 2022 09:53 #868209 by BertClicteur
Broken carbs was created by BertClicteur
After opening up the carbs on my 1982 GPZ750 I discovered some damage.
There's a metal plug with an o-ring to close off the pilot jet.
On one of the carbs the housing is broken so the o-ring doesn't seal anymore.
My local scrapdealer said it would be a shame to throw out the carbs for that(also I can't seem to find a set anyway).
He said it's unusual to have metal plugs rather than the more common rubber ones.
In his garage he had a rubber plug that fits, but I wonder if it will be enough.
Carbs aren't my specialty so all help is welcome...
 
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04 Jun 2022 10:20 - 04 Jun 2022 10:21 #868215 by Mikaw
Replied by Mikaw on topic Broken carbs
Without knowing your specific carb is it possible to cut horizontal across at the damaged spot and vertical down to your first cut and give you a square end of the casting.

 

1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.
Last edit: 04 Jun 2022 10:21 by Mikaw.

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  • SWest
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04 Jun 2022 10:34 #868217 by SWest
Replied by SWest on topic Broken carbs
As long as it doesn't go too far down and block the jet a little JB weld on the outside might help to seal it.
Steve

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  • BertClicteur
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04 Jun 2022 10:44 #868219 by BertClicteur
Replied by BertClicteur on topic Broken carbs
I see what you mean, but that's dangerous stuff cutting into it like that.
Alltough now I only have like a millimeter of play so I might have to...
I'll need to check if I don't block the supply by doing so.
Also now the float bowl pushes down on the rubber so it can't get out.
They're Mikuni's btw, I wonder if I could change them for the same carb of a different bike?
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04 Jun 2022 10:47 #868220 by Nessism
Replied by Nessism on topic Broken carbs
PLEASE user "insert" when posting photos, so they show up properly.

Any kind of plug that seals the passage will work.  The float bowl helps hold the plugs in place, so realize that when creating your new plug.
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04 Jun 2022 10:58 - 04 Jun 2022 10:59 #868222 by Mikaw
Replied by Mikaw on topic Broken carbs
You can look for a donor body. Or as Swest says. Epoxy of your choice. Keep the rubber plug in as a mandrel and build put the outside to correct the damage 

1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.
Last edit: 04 Jun 2022 10:59 by Mikaw.
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  • Scirocco
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04 Jun 2022 12:15 - 04 Jun 2022 12:15 #868228 by Scirocco
Replied by Scirocco on topic Broken carbs

Without knowing your specific carb is it possible to cut horizontal across at the damaged spot and vertical down to your first cut and give you a square end of the casting.

 
If you cut out anything, you will loosen the bowl pressure. Use some drops of permanent sealant or epoxy to fill the damaged area.
Last edit: 04 Jun 2022 12:15 by Scirocco.
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  • BertClicteur
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13 Jun 2022 09:20 #868715 by BertClicteur
Replied by BertClicteur on topic Broken carbs
So I received the JB weld, but it doesn't say it can withstand fuel.
I contacted the company and they said with ethanol gas it’s now hit or miss.
It tends to break the epoxy down over time.
So I'm not too sure on using it.
I have a testpiece in a jar with soms gas, so maybe that'll tell me more...

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13 Jun 2022 09:29 #868716 by Nerdy
Replied by Nerdy on topic Broken carbs

So I received the JB weld, but it doesn't say it can withstand fuel.
I contacted the company and they said with ethanol gas it’s now hit or miss.
It tends to break the epoxy down over time.
So I'm not too sure on using it.
I have a testpiece in a jar with soms gas, so maybe that'll tell me more...
 

Which JB Weld did you buy? There are different types.

The Tank Weld should not be affected by fuel.



 

1979 KZ400 Gifted to a couple of nephews
1967 Yamaha YCS1 Bonanza
1980 KZ440B
1981 Yamaha XT250H
1981 KZ440 LTD project bike
1981 GPz550
2013 Yamaha FZ6R
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  • gd4now
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  • Denco where did you go?
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13 Jun 2022 14:18 #868727 by gd4now
Replied by gd4now on topic Broken carbs
IIRC there was a topic here in the recent past ( I am old and do not recall how long ago) that a member, sorry do not remember who so not going to attempt to name them, that a new to me product was used to rebuild the float legs and other things on the bottom of the carb body..  I will attempt to find it but no promises. But as I recall there were great pics and a good review of the product.  Anybody else remember it?

1977 KZ650 B1
Pods and Denco header


OLD KAW OWNERS SMILE ALOT

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  • Scirocco
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13 Jun 2022 15:51 #868730 by Scirocco
Replied by Scirocco on topic Broken carbs
AFAIK, he use some kind of liquid or plastilage metal repair compount.

 

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13 Jun 2022 16:06 #868731 by Nessism
Replied by Nessism on topic Broken carbs
I'm not familiar with that TankWeld product, but I do know that regular JB Weld will break down in gasoline.  

Aircraft fuel tank sealer, a polysulfide product, will work.  Personally though, I'd fashion some sort of mechanical repair.

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