1981 Fuel line diaphragm

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Miikiel
Posts: 3
Joined: Mon Oct 13, 2014 9:38 am

1981 Fuel line diaphragm

Postby Miikiel » Wed Feb 11, 2015 8:28 pm

Hi I am looking for a good working fuel line diaphragm or maybe a rebuild kit? If you have one please let me know. thanks

Mikel

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Folsoml
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Location: North Florida

Re: 1981 Fuel line diaphragm

Postby Folsoml » Thu Feb 12, 2015 6:05 am

Are you talking about the automatic fuel valve? If so, do you know you can just bypass it? I don't see a rebuild kit for it, and the valve itself is no longer available.
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Miikiel
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Joined: Mon Oct 13, 2014 9:38 am

Re: 1981 Fuel line diaphragm

Postby Miikiel » Thu Feb 12, 2015 8:51 pm

Image

my clymer book and this image call it the fuel line diphragm. My bike is getting too much gas and having one of these that works correctly should fix it, i hope

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Volker_P
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Re: 1981 Fuel line diaphragm

Postby Volker_P » Fri Feb 13, 2015 2:42 am

Welcome here, Mikel! :D

This is the vacuum shutoff valve. It shuts down the fuel line when the engine is not turning e.g. when the bike is parked with the petock still open because the rider forgot to close it. So not really required (and not all CV carbs have it) and moreover no flow regulator for the fuel when running. Particulary, if it is not leaking itself, it probably works properly in your case.

So the question is what means 'too much fuel' and why do you think that? If fuel is leaking from the carbs, it is probably either floater valves (which typically means dirt in the tank) or the "vacuum tees" (which may cause leakage when they are cracked which seems a quite common issue if you have a look in this forum).

If you need to go inside your carbs, here you can find a link to a nice manual for CV carbs: viewtopic.php?f=4&t=5056&start=3
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

Miikiel
Posts: 3
Joined: Mon Oct 13, 2014 9:38 am

Re: 1981 Fuel line diaphragm

Postby Miikiel » Sat Feb 14, 2015 8:42 pm

Thank you for the info. I am new to carbureted bikes so I'm leaning on the help of the friend of the family. I ended up finding a rebuild kit off eBay for the vacuum shutoff. I got the bike from my father in law after he passed away and it was leaking then after he "rebuilt" the carbs. i ended up buying a set of carbs off eBay after the ones that were on it wouldn't stop leaking. The new set of carbs leaked as well but we noticed that it had the vacuum shutoff which the other set didn't. The rubber check valve was pretty worn. I got the new one today. Ill post whether or not it fixes it. Thanks again.

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Folsoml
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Location: North Florida

Re: 1981 Fuel line diaphragm

Postby Folsoml » Sun Feb 15, 2015 7:46 am

Are the carbs leaking from anywhere other than float bowl nipple? Are they leaking even while the bike is running? Neither of these two problems will likely be fixed with your new part. Go through your carbs using this manual. It will not be exactly like your carbs, but it will be close enough. Pay attention to the part about polishing the float needle seat and inspecting the float needle.
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