Need Help setting Float Level. 2nd Gen VFR750

Setting up/fabricating a gravity fed system is very straightforward. For reference Motion Pro makes an auxiliary tank.

Motion Pro - Auxiliary Fuel Tank

 

Ok....so i went out and got some hoses and a bucket thingy with a drain on the bottom....i set it up above the carbs hanging from the ceiling and hooked up the line.
After checking everything I added some fuel and watched in dismay as a thousand tiny holes in the bucket started to leak fuel. When the bucket started to fill up the leaks got crazy worse and fuel started to pool under the carbs. (i don't know if it was from the leaky bucket or from the carbs)

So after cleaning up and opening the one window in the basement, I hooked up a 2 ft hose to a tiny spout and slowly poured fuel in until it came out of the spout....then I stuck the hose above the carbs. (see attached pic)



I don't know if I need to have a large body of fuel above the fuel line in order for the test to be valid but this is the best i can do.

 

Stop fretting, Matt, and install the carbs already. Your testing method is only partially valid cuz carbs are under 3psi pressure from fuel pump during operation.

 

but the carbs leaked when the bike was just sitting....just resting on the side stand not running

 

If they are not leaking after you have bench tested them you are good to install.

On a slightly different subject you mentioned in an earlier post that the new float needle has a different code. SM mentioned that this is okay though I would think they should all have the same code. Not calling SM out to the town square here but I would appreciate a bit more info this.

 

I really hope it's ok....I'd hate to have to dish out more cash to replace all float assys.

 

For ref, here is the original post:

http://vfrworld.com/forums/1st-2nd-generation-1983-1989/31865-goodbye-1st-gen-hello-2nd-gen-6.html#post303325

I'd be interested to read a more detailed description of how this affects the float level. I would think for clarity you would want to have the same float needle & float seat and subsequently the same float setting.

It seems overly complicated to have different float settings in the same set of carburetors, IMO.

 

I just got back from Honda...spoke to my buddy that works in parts.

The old part number for the float assemblies has been superseded. So Honda only supplies the one that I installed with the .2mm larger number

 

Thanks for the post.

I would think that all the float needles/seats should be the same spec if you are setting all the floats to the same height.

I am curious to see how the carb pros weigh in on this.

 

I'd think (and hope) that the only difference is the inlet size. (2.6 vs the older 2.4) So there is a 0.2mm difference. So the fuel will flow ever so slightly more....but only when the float is all the way down and pulling the valve completely open.

I didn't notice any difference in the valve and I can't see why Honda would change the float valve size making the float height spec set in Honda service manuals obsolete.

My friend at the Honda Dealership think it won't be an issue....and I hope him and SM are correct.

 

Clarification: Original (1986) size is 2.6 and REPLACEMENTS are 2.4

Set all the floats the same, and ride the bike. If any running problems, then do some plug cuts and inspect colours for consistency.

 

Thanks for the clarification. I'll be curious to hear if this size difference will require a different float setting. On this note, perhaps their was an FSB regarding this change?

 

i don't believe the very slight difference in fuel inflow would require any change from stock float height setting; however, if the needle is even slightly longer or shorter ( i think it may be) then that would have an effect on proper float height becuz, with a setting by the book, the fuel would be stopped sooner or stopped later by a non-stock length needle.

 

Most respectfully, i disagree.

With a very long needle, for example, you'd need to adjust the float tab to close inlet later at a given float height. Does this make any sense ?

Or, at a standard float setting, a longer needle would be closing off the inlet earlier, resulting in a lower than standard fuel level.

 

Tink, if you have your pencil and sketch pad handy I would appreciate a section detailing your take on this.