carb over flowing issue
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Junior Member
Squid
Joined: Jan 2017
Posts: 6
carb over flowing issue
Hi all... I just cleaned out the carbs from a super hawk thats been sitting a while. 15 years.. put it all together and it fired up... later that night i smelled gas in the garage.
notice gas leaking from carb, took carbs out again noticed gas had over flown and filled up cylinder... floats looked good, so i ordered new float valves... does this sound right to you guys? ... it has to be the valve sticking causing the float to stay open allowing all the gas to over flow and fill up the cylinder... I was able to suck up all the gas from the cylinder... please all advise welcome.
notice gas leaking from carb, took carbs out again noticed gas had over flown and filled up cylinder... floats looked good, so i ordered new float valves... does this sound right to you guys? ... it has to be the valve sticking causing the float to stay open allowing all the gas to over flow and fill up the cylinder... I was able to suck up all the gas from the cylinder... please all advise welcome.
VTR virgin
Superstock
Joined: Mar 2015
Posts: 447
From: Auckland, New Zealand
The other place to check is the vacuum petcock under the tank; these can also stick open allowing gravity to do it's thing. In conjunction with a float valve not sealing perfectly, that will lead to an overflow; I had exactly the experience that you describe. The petcock is a standard Honda design and you will be able to locate a rebuild kit for the diaphragm from K&L if not OEM.
Thread Starter
Junior Member
Squid
Joined: Jan 2017
Posts: 6
The other place to check is the vacuum petcock under the tank; these can also stick open allowing gravity to do it's thing. In conjunction with a float valve not sealing perfectly, that will lead to an overflow; I had exactly the experience that you describe. The petcock is a standard Honda design and you will be able to locate a rebuild kit for the diaphragm from K&L if not OEM.
VTR virgin
Superstock
Joined: Mar 2015
Posts: 447
From: Auckland, New Zealand
Fuel should only flow to the carbs when there is a vacuum to the petcock. If you disconnect a fuel hose at one of the carbs and drain that to a bucket, and then draw a vacuum (your mouth is fine) on the thin vacuum tube plugged into the back of the petcock, fuel flow should start, and then stop when the vacuum is released (there may be a small time lag before it cuts off fully, a few handfuls of seconds). If fuel is flowing without vacuum, your petcock is stuck open.
The front of the petcock is square peg that operates a manual fuel tap. IIRc you turn this full clockwise half a turn with an 8mm spanner to shut it off (or it might be counterclockwise!).
The front of the petcock is square peg that operates a manual fuel tap. IIRc you turn this full clockwise half a turn with an 8mm spanner to shut it off (or it might be counterclockwise!).
Thread Starter
Junior Member
Squid
Joined: Jan 2017
Posts: 6
Fuel should only flow to the carbs when there is a vacuum to the petcock. If you disconnect a fuel hose at one of the carbs and drain that to a bucket, and then draw a vacuum (your mouth is fine) on the thin vacuum tube plugged into the back of the petcock, fuel flow should start, and then stop when the vacuum is released (there may be a small time lag before it cuts off fully, a few handfuls of seconds). If fuel is flowing without vacuum, your petcock is stuck open.
The front of the petcock is square peg that operates a manual fuel tap. IIRc you turn this full clockwise half a turn with an 8mm spanner to shut it off (or it might be counterclockwise!).
The front of the petcock is square peg that operates a manual fuel tap. IIRc you turn this full clockwise half a turn with an 8mm spanner to shut it off (or it might be counterclockwise!).
also.. just tested my float needles, the one shuts the gas off when the float goes up, the other keeps leaking gas... I will test out the petcock later tonight when I get home... I believe I am on the right track?
VTR virgin
Superstock
Joined: Mar 2015
Posts: 447
From: Auckland, New Zealand
ok... thank you.. My carbs are off right now... So I should be able to turn the fuel valve on and have no gas coming out of the petcock... ..
also.. just tested my float needles, the one shuts the gas off when the float goes up, the other keeps leaking gas... I will test out the petcock later tonight when I get home... I believe I am on the right track?
also.. just tested my float needles, the one shuts the gas off when the float goes up, the other keeps leaking gas... I will test out the petcock later tonight when I get home... I believe I am on the right track?
No fuel will flow with the manual tap turned off
No fuel should flow with the manual tap open and no vacuum applied
Fuel should flow with the manual tap open and vacuum applied
Fuel should only overflow from the parked bike if the vacuum petcock and at least one float valve are faulty.
On my bike, I rebuilt the petcock but did not open the carbs, and my leak stopped.
Thread Starter
Junior Member
Squid
Joined: Jan 2017
Posts: 6
Sounds about right:
No fuel will flow with the manual tap turned off
No fuel should flow with the manual tap open and no vacuum applied
Fuel should flow with the manual tap open and vacuum applied
Fuel should only overflow from the parked bike if the vacuum petcock and at least one float valve are faulty.
On my bike, I rebuilt the petcock but did not open the carbs, and my leak stopped.
No fuel will flow with the manual tap turned off
No fuel should flow with the manual tap open and no vacuum applied
Fuel should flow with the manual tap open and vacuum applied
Fuel should only overflow from the parked bike if the vacuum petcock and at least one float valve are faulty.
On my bike, I rebuilt the petcock but did not open the carbs, and my leak stopped.
Thread Starter
Junior Member
Squid
Joined: Jan 2017
Posts: 6
Thread Starter
Junior Member
Squid
Joined: Jan 2017
Posts: 6
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