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Hello all I have a 1984 Honda Magna VF700 that when the rpm's under a load reach appx 5500 it starts to sputter and will not accelerate any further. I have cleaned the carbs,fuel tank and changed the fuel filter and still has the same problem. I checked the fuel cap vent and it seems to be fine. I had it running and noticed that there was fuel coming out of the fuel cap and after opening the cap it appears as if there were tiny air bubbles inside the tank fuel as well while running?? I would appreciate any help I can get on this one have never experienced this before.
 

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Hello all I have a 1984 Honda Magna VF700 that when the rpm's under a load reach appx 5500 it starts to sputter and will not accelerate any further. I have cleaned the carbs, fuel tank and changed the fuel filter and still has the same problem. I checked the fuel cap vent and it seems to be fine. I had it running and noticed that there was fuel coming out of the fuel cap and after opening the cap it appears as if there were tiny air bubbles inside the tank fuel as well while running?? I would appreciate any help I can get on this one have never experienced this before.
Let's start with the fact that the whole fuel system is at least thirty eight years old.
The setup of the VF700 is a bit unusual: to keep the fuel tank small they placed a second tank plumbed to the main tank. This requires a fuel pump to feed the carbs. From your description I'd say the only components you haven't checked are the fuel pump, the fuel pump stop relay (There to stop the fuel pump in the event of a tipover, and is prone to failure.), the fuel sub tank, and the feed from the main tank to the sub tank. Any restriction in the fuel path such as a pinched transfer hose, accumulation of water / contaminants / whatever in the sub tank, and / or a failing fuel pump will restrict flow to the carbs at higher revs.
A link to the fuel pump and stop relay: 1984 Honda VF700C A BATTERY / FUEL PUMP | Ron Ayers
You're going to have to delve deeper into the fuel system.

Good luck!

Rob
 
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Discussion Starter #4
Thank you today I checked the fuel supply hoses from main tank to reserve tank and noticed that the smaller hose was slightly kinked so I pulled it and rerouted it eliminating any kinks. The weather here was bad today so if better tomorrow I will road test and inform you as to the out come. The bike had been sitting for a long time so I ordered both a fuel pump and a fuel relay which I will try one at a time to see if the issue is corrected if the fuel hose issue is not the problem
 

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All the Diaphragms should be checked also.
Thank you for your response I am hopeful the problem is other than the carbs I did not replace the diaphragms but did pull them for cleaning purposes. This bike had been sitting for a long time so it may very well be 1 or more cracked diaphragms. My luck with this bike has not been the best so I am prepared to pull carbs again if needed.
 
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