Topic: Bonneville Turbo CB500/550

[kayaker43]

I'm with Scottly on the pump,.. Regardless of how it may have been used, its supposed to suck fuel from the bowl and squirt it down the carb throat whenever the throttle is opened. Its supposed to be cable driven off the throttle.

Completely different than a fuel pump who's purpose is to keep the float bowl full.

[Retro Rocket]

I'm with Scottly on the pump,.. Regardless of how it may have been used, its supposed to suck fuel from the bowl and squirt it down the carb throat whenever the throttle is opened. Its supposed to be cable driven off the throttle.

Completely different than a fuel pump who's purpose is to keep the float bowl full.

I'm with Greggo, its a custom made set up to keep the bowls full due to the extra fuel used to feed the engine under boost, my old drag bike  had 2 petcocks and fuel lines to keep the fuel coming, an electric fuel pump would do the same thing...

[kayaker43]

Makes no sense?? The squirt volume from those pumps is way too small and what on earth would have driven them by cable? It would take you 50 squirts to fill a float bowl. They were sold as cable driven accelerator pumps to improve throttle response. I remember installing these for people back in the 70's

You must be confusing them with similar fuel pumps that have much bigger diaphragms and are driven by crankcase pulses.  You typically see these on snowmobiles.

[Greggo]

I'll let you guys debate it if you please, but I've spoken with the man who put the kit on his 550 in the late 70's, and modified the carb with the pump to keep the bowl full, or keep it from drying up at the least. 

[scottly]

Look at this way: if you want to ensure the float bowl is full to the proper level, you would have a pump between the fuel tank and the normal carburetor input, so the float can do it's job.
That is obviously an accelerator pump, and, depending on the location of the jet within the carb throat, may also act as a high-speed enrichment jet. 

[ivanhoew]

i created that sort of high speed enrichment  on my 400/4 turbo , with the xs650 carb , i ran a pipe from the drain on the float bowl ,and placed its end in the airstream about 2/3rds of the way up th carb inlet .using a bit of brake pipe ,and crimped the end to create a nozzle ,it was suprisingly effective.

[Greggo]

I went back to the emails exchanged when I bought the kit, and the pump attached is indeed an accelerator pump.  There was a separate pump between the tank and carb.  I'd forgotten he had ditched that pump long ago because it was too big, and just remembered there was a pump to keep the bowl full.  My apologies for the confusion Gents.  I'll need to find a good sized pump to do that job, and I will set the current one up as a Go-Fast button.

From the seller:

The fuel pump was a lost cause and I pitched it years ago it was a stewart warner thing that was too big anyway.

[Retro Rocket]

Yes, after thinking about it it could not fill the bowls, interesting set up though....

[scottly]

he had ditched that pump long ago because it was too big, and just remembered there was a pump to keep the bowl full.  My apologies for the confusion Gents.  I'll need to find a good sized pump to do that job,that was too big anyway.

The PO of my bike had installed a huge fuel pump, about the size of a can of beer, plus a fuel pressure regulator set to about 2-1/2 pounds. I guess he thought the Webers wouldn't work with gravity feed. As long as you have an adequate flow though the petcock, you shouldn't need a pump. If you chose to run a pump, look into Facet Cube pumps; they are only about 2 1/2"x 2 1/2", and draw about 1.6 amps.

[Retro Rocket]

he had ditched that pump long ago because it was too big, and just remembered there was a pump to keep the bowl full.  My apologies for the confusion Gents.  I'll need to find a good sized pump to do that job,that was too big anyway.

The PO of my bike had installed a huge fuel pump, about the size of a can of beer, plus a fuel pressure regulator set to about 2-1/2 pounds. I guess he thought the Webers wouldn't work with gravity feed. As long as you have an adequate flow though the petcock, you shouldn't need a pump. If you chose to run a pump, look into Facet Cube pumps; they are only about 2 1/2"x 2 1/2", and draw about 1.6 amps.

Or run 2 petcocks....

[Old Scrambler]

I drained my bowl on two separate runs at the salt flats. Who would think a little 201cc single could drain a Mikuni 29mm carb

The quick fix was to raise the float a tad and it worked

But the real fix is to have larger diameter holes in the brass fuel lines where the rubber fuel line attaches. The check list is.............measure the petcock flow volume with a timer.........then add the line and check again.........then add the fuel filter (if you use one) and check again............then add the carb and check the flow with the bowl removed.  Any reductions should be eliminated

[bwaller]

I have a dual outlet Pingle you can drive a truck through.

It'll pass gas!

[DustyRags]

Hey Greggo, any updates on this baby?

[Greggo]

It just sits, trapped in a corner...I did get a clear california title for it, but I don't have space to work on it for now.  I turn the motor over every few months, but that's about it.

[Stev-o]

Doesnt seem possible that you bought that bike over 3.5 years ago....

[Greggo]

Doesnt seem possible that you bought that bike over 3.5 years ago....

I know...I had to watch the video of it running again I'll street it some day..

[Stev-o]

Doesnt seem possible that you bought that bike over 3.5 years ago....

I'll street it some day..

I know you will....or it gets shipped to Texas!

[Tews19]

No #$%*, 3.5 years ago! Time has really gone by fast!

[Lostboy Steve]

Not to change the subject, but is that a g60 on that Bus? Did that project take priority?

[Greggo]

Up for sale: http://www.ebay.com/itm/331911270890?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649