Baffled by fuel feed, anybody been there before?

Sweet, I got a k and L unit on the way, and also snagged a stocker out of a Yamaha V Star 650 with 6k miles on the clock. It's a dead ringer for the Honda unit and should push the same psi. That one can live under the seat as a spare.

The last thing the bike needs is neck bearings.

Thanks for the help, folks.

Oh, the relay. Some of y'all said it's problematic. Do most folks bypass it, or keep replacing it?

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wiring a switch to bypass the pump is good insurance and will be useful to fill the carbs after a few weeks of not riding.

 

thanks, I've used a connector at the pump that will let me unhook it easily and put the positive lead straight to the battery. I did this for testing but it will be useful for filling carbs after sitting up (like that ever happens here in Charleston, SC ).

 

Good choice on both pumps.

Wiring the relay for a parallel bypass is super handy. Most of mine I can switch on the fly, or reach under somewhere for an instant road side "repair'.

 

Wonderful, I can put a little switch just about anywhere. I think I'm about done with reliability issues on this bike. Next are neck bearings and braided clutch/brake lines, and I think all the "old" stuff issues will be finished, for now at least.
Some random guy in a pickup truck screamed at me at the stop light that he "knows all about motorcycles" and my valves were slapping. This was the same guy holding up traffic in the fast lane, so I'm not so sure he knows shyt from Shinola. I might not know a lot about fuel pumps, but I've done a whole lot of in-line four valves, and I think these are fine. I can hear the gear driven cams, but I don't hear any worrisome valve train noises.

 

"Yeah.... ok dude. thanks." {rolls eyes}
He has probably never heard spring-loaded cam gears before.

Shit, my 86 VFRs are NOT quiet motors, but I know everything is perfect.

 

Just so you are aware - the ONLY purpose of the relay bypass switch is to PRIME the fuel pump. It is NOT to be used in normal running - nor should it be needed. You flip it for about 3-5 seconds and its done its purpose. My CBR400rr if not used for over a month, then I need to prime the pump. If used daily, then no issues. These old pumps were fine at pumping fuel, just really crap at sucking it.

 

UNTIL the relay fails in the middle of a floating bridge or out in a remote farming river valley. And then you do use it for normal running. To get your ass outa there!

Both examples from personal experience. The floating bridge incident was awesome. My friends were impressed, especially my buddy also on a 1986 VFR.
"What happened?"
"I know I have fuel so I'm pretty sure my fuel cut relay just failed" (I fucking knew it)
"Shit, what are you gonna do?"
"I'm gonna flip this switch under my left side cover and we're gonna go drink beer at your cabin."

tk, tk, tk, tk..... tk...............tk..................

"Let's go!"

 

Agreed - but not quite the situation for the op - yet....

 

You never know when that little black box is gonna try and fuck you. I'd rather spend a half hour at home in a well it area, sipping some whisky, listening to music, while wiring my parallel toggle then spend any time on the side of the road fiddling about with power to the pump or coming up with some kind of jumper.

It's not if with those things, it's typically when. I have some original units now 35 years old. No need to replace what's not bad yet, knowing I have an insurance policy.

And like you noted, the prime feature alone is worth a nice little switch.

 

Hahaha I've been stuck in some bad places too, switch for it relay it is!

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OK, let's suppose the pump itself has failed...................

i've wanted to post about this forever but never got around to scoping it out fully, but i'm sure captain 80's will take over: "how to use a spare hose kept on the bike to lead fuel from the petcock to the carbs (no fuel pump). hose diameter and length ?

just to get home, and i had to use it once years ago but forgot details. the fuller the tank is the better it works.

captain, please enlighten us about this emergency fix, good sir.

 

AAA

Actually I've never had to figure this out. Next time I have the tank off of one I'll take a look. I think for real emergency purposes I would just cut the return fuel line at the appropriate length to meet the petcock and deal with replacing the fuel line later? That's if the fuel lines are supple enough to allow that. Isn't there a coupling right in that area that might help with a nice piece of formed fuel line? Maybe a u-shaped piece of metal tubing to "replace" the fuel pump would be enough. But then a FULL tank would help I suppose.

I don't tend to carry around emergency spare parts, but all of my tank bags have a 3 inch solid core jumper wire. I usually have to lend it out. I hot wired a Sabre for someone once. They were amazed how easy it was and it let them ride the rest of the day.