Fuel pump absolutely necessary on a 1985 VF700?

Just read a post from friend in Holland (Holland is below sea level) Who has rebuilt many VF750F's from the ground up. A mechanic on a racing team for these bikes. He knows his stuff.
He replied that he has problems with fuel starvation with the tank fed directly to the carbs. So this disproves the "elevation, atmospheric pressure theory". If Jamie Daugherty can make this work. I don't see why anyone else can't make it work either.
I'm tellin ya there has to be a solution and a simple one. :smile-new: Having to stop for fuel every 60 to 90 mins would just suck.

 

There is a law of physics involved in that but it is not gravity.

 

Yea what's the big deal?? Put a pump on it. Well worth the money compared to the hassle. "Having to stop for fuel every 60 to 90 mins would just suck."

 

What "I WANT to hear"? I have heard only one answer to get around the problem and that's buy a pump. I have no argument about that. The old Honda accord pumps I believe it is. The point of this thread is that it does work without issues for others without a pump. You seem to have just thrown in the towel and given up.
Pull the petcock off the tank and tell us how much fuel comes out of it. You'll get all of it out but a cup or so.

 

Yes, this topic has been hotly debated, however much of it is opinion and suspicion. I will tell you that all of my first generation VF's run gravity feed and they run perfect and will use all of the fuel from the tank.

If you have the tank off the bike and on the bench - then open the petcock - won't all of the fuel drain out? Sure it will. That's exactly what happens when it is on the bike too. I'm not sure where the 1/3 tank thing ever started but it simply isn't supported by fact.

 

My ears are ringing after that one.

 

Not sure what question you are referring to.

My bikes are not track bikes. They are street bikes ridden in 40-90 degree temps, city and rural conditions, etc. Gravity feed has been done many times to first gen VF's. Only a few people have not been able to make it work - and my conclusion was something else was wrong in the system in those cases.

 

+1 on the 42s

I've got one squeezed in one of my CB-1's. Had to shave the mounting tabs off to get it to fit, but 40 bucks available everywhere. Hard to beat for that price.

 

I gotta side with tinker on this one. Honda engineers are not known to stuff useless doodads in there for no reason.
Could you do it? Sure, but it probably won't run as well as if you had a pump on there.

 

Pump HAS to be there for a good reason.

But i've always carried a short length of fuel line under the seat to connect tank to carbs if the pump quits and gravity will get me home.

 

If you can ride my bike off on a gallon of fuel, gravity fed, I will stick the title in your pocket as you ride off and please do not look back. If you need my help to push the bike back.........your mom or sister better have some mad skill's orally. Bike,gas, and title are here for the taking.

 

Just say'n

 

thats like ovekill to a simple obviuouness, but icommend the effort and the science knowledge.