Can anyone ID this part for me?

[erkishhorde]

How about easy?

Go to the local parts store and buy anything with the right size nipples.

It will work.

I use Delco pumps as they seem to work for years...and years...

and that's right...

years.

They aren't necessarily cheap.

You have no idea how hard that part was if you didn't want to take one of the ones that they have on the shelf at AutoZone or Pep Boys. Those things are HUGE and like $75 too!  I don't remember how, but I got the guy at Autozone to look up fuel pumps for old cars. It was like an '87 Chrystler or something. I still have the box somewhere. I've got a big deadline on Friday that I need to work on. If I remember I'll post up what I did on the weekend but I had gotten some help from someone else too. Lol. I think  I still have my PMs to give credit.

[junior varsity]

Awesome - do tell. You have two friday deadlines now. One is info and pics of the pump! 

[erkishhorde]

Alright, I'm back from my meeting. Starting to gather things to do this write-up since I'm planning on making tomorrow a bike day and do a few things that I've been meaning to do for a loooooong time.

Maalox, can I steal this picture so I don't have to take off my air box to take my own?

[ducpainter]

how about size?   Are the Delcos compact?  I think that is a goal here.

Compact enough to hide on a carby. Most of you guys have no airbox anyway. How much room do you need to hide shit?

I'm not about the looks...I'm a function kinda guy

[DucNaked]

I'm not about the looks...I'm a function kinda guy

Says the painter 

[ducpainter]

Says the painter 

you've seen my bikes.

[MaaloX]

Maalox, can I steal this picture so I don't have to take off my air box to take my own?

[/quote]

You sure can!

[erkishhorde]

Awesome - do tell. You have two friday deadlines now. One is info and pics of the pump! 

Gonna take me a little while to get to this. Got a lotta work to do now that my meeting is over. Getting 3 wisdom teeth out on Wednesday morning too. 

[Cloner]

Stuart and I worked on a bike last summer that had an aftermarket fuel pump (vacuum, but not the stock one) that the owner bought from Chris at CA-Cycleworks.  It was this one:



The bike ran out of fuel once it got hot.  We opened the float bowl drains and absolutely NOTHING came out!  We couldn't find anything wrong with this pump except that it moves nowhere near the volume that the stock pump is rated to move.  We quizzed the PO about why he replace the stock pump with this one and he said he did it because it was cheap.

He happened to still have the stock pump, so we bought a Mikuni rebuild kit for it from Sudco, rebuilt the pump in about 15 minutes, and the bike has run well since.  I can't explain why this occurred, but empirically, this solution worked.  Go figure!   

I talked with Chris and he said he has sold tons of these pumps and has never had a complaint, so we're not sure what's going on in this instance.  I suspect a vibration problem, but I haven't done the math to prove it.  This anecdote is related to you in case you, too, have issues with the aftermarket pump. 

I think the rebuild kit was about $20....much less than even the "cheap" alternative.

YMMV

Cloner
Co-Proprietor and mechanic (and mechanical engineer....in case you need someone to spec a fuel pump, Nate )
Desert Desmo, LLC
ABQ, NM

[671M900]

I have the exact same one from chris. Never had a problem.

Stuart and I worked on a bike last summer that had an aftermarket fuel pump (vacuum, but not the stock one) that the owner bought from Chris at CA-Cycleworks.  It was this one:



The bike ran out of fuel once it got hot.  We opened the float bowl drains and absolutely NOTHING came out!  We couldn't find anything wrong with this pump except that it moves nowhere near the volume that the stock pump is rated to move.  We quizzed the PO about why he replace the stock pump with this one and he said he did it because it was cheap.

He happened to still have the stock pump, so we bought a Mikuni rebuild kit for it from Sudco, rebuilt the pump in about 15 minutes, and the bike has run well since.  I can't explain why this occurred, but empirically, this solution worked.  Go figure!   

I talked with Chris and he said he has sold tons of these pumps and has never had a complaint, so we're not sure what's going on in this instance.  I suspect a vibration problem, but I haven't done the math to prove it.  This anecdote is related to you in case you, too, have issues with the aftermarket pump. 

I think the rebuild kit was about $20....much less than even the "cheap" alternative.

YMMV

Cloner
Co-Proprietor and mechanic (and mechanical engineer....in case you need someone to spec a fuel pump, Nate )
Desert Desmo, LLC
ABQ, NM

[Howie]

Stuart and I worked on a bike last summer that had an aftermarket fuel pump (vacuum, but not the stock one) that the owner bought from Chris at CA-Cycleworks.  It was this one:



The bike ran out of fuel once it got hot.  We opened the float bowl drains and absolutely NOTHING came out!  We couldn't find anything wrong with this pump except that it moves nowhere near the volume that the stock pump is rated to move.  We quizzed the PO about why he replace the stock pump with this one and he said he did it because it was cheap.

He happened to still have the stock pump, so we bought a Mikuni rebuild kit for it from Sudco, rebuilt the pump in about 15 minutes, and the bike has run well since.  I can't explain why this occurred, but empirically, this solution worked.  Go figure!  

I talked with Chris and he said he has sold tons of these pumps and has never had a complaint, so we're not sure what's going on in this instance.  I suspect a vibration problem, but I haven't done the math to prove it.  This anecdote is related to you in case you, too, have issues with the aftermarket pump.  

I think the rebuild kit was about $20....much less than even the "cheap" alternative.

YMMV

Cloner
Co-Proprietor and mechanic (and mechanical engineer....in case you need someone to spec a fuel pump, Nate )
Desert Desmo, LLC
ABQ, NM

I had the same problem with that pump.  The pump, though it does put out less volume than the stock pump, should run a stock bike fine.  Chris has sold quite a few to happy customers so I must assume they usually do.  My guess?  Alcohol poisoning or an occasional bad pump.

[ducpainter]

<snip>
Cloner
Co-Proprietor and mechanic (and mechanical engineer....in case you need someone to spec a fuel pump, Nate )
Desert Desmo, LLC
ABQ, NM

'ain't rocket science bro...

anything that will maintain 3-4 psi at any volume over 1 gpm should work.

[Cloner]

'ain't rocket science bro...

anything that will maintain 3-4 psi at any volume over 1 gpm should work.

Agreed....and it ain't rocket science.  That's what I tell everyone about 99.9% of the crap I do in my capacity as an engineer, too, though.

Again, I can't explain why this pump didn't work.  It moved fuel well at idle, but when things got moving the fueling stopped.  I'm certain the pump works in many applications.  Heck, it's marketed for use in ultralight aircraft where the consequences of failure are catastrophic, so I'm sure it's not junk.  As I said, I suspect that vibrations caused the diaphragm or the check valve in the pump to act strangely, but I can't prove it....but it's the only explaination I can conjure up to explain why the pump would work at idle but not at higher revs.  It could be that the vacuum pulse spacing that the pump depends upon to pump fuel disagreed with the pump at higher revs, but the same vacuum line/tap combination worked with the stock pump without adverse effects, so I'm at a loss to explain it.  The good news is, I don't have to explain it.   

I just thought this story was worth publishing so that others who might have problems with aftermarket fuel pumps on their carbie Monsters won't think they're insane.

For what it's worth, we did everything imaginable before we replace this pump, assuming that it worked correctly at speed because it worked well at idle.  We cut the vacuum petcock out of the circuit to see if it was the culprit.  We replace all of the fuel lines in case one was collapsing at speed due to higher flow.  We replace all the vacuum lines incase one of them was collapsing at speed due to higher (lower?) vacuum (negative pressure).  We checked the valves to make sure an opener wasn't binding up when the bike got hot....all we knew at the time was that the bike ran poorly then shut off when it got hot.  We rerouted the fuel lines away from the exhaust pipe (they had been replaced in the past) and reintroduced the factory hose between the tank and the fuel filter in case there was a vapor lock issue (since all of this is upstream of the pump).  We swapped the ignition modules temporarily just to make sure there wasn't an issue with the original ones.  The fuel pump replacement was a desperation move of last resort.  I'm sure all of this is out of order, but you get the idea.  We weren't clued in that fuel delivery to the carbs was the problem until we rode the bike until it stalled and immediately opened the float bowl drains.

Anyway, I hope that this story helps someone else avoid similar problems down the road sometime.  The moral of the story is that as long as the housing is intact, it's cheaper and more effective to simply rebuild the stock fuel pump on your carbie Monster than to replace it with an alternative!

[junior varsity]

Interesting.

I've had a fuel-starvation like feeling while riding at 'very high speeds' after wailing on the bike for quite awhile like that Mikuni pump was having difficulty getting fuel to the carbs as well. It would stumble and such. I wonder if I'm having a similar issue - but its only occasional - there's very little predictability to this.  And I thought I'd experienced similar 'stumbles' with the pentagon shaped Mikuni too.

intake isn't highly modified really - just banked FCR 41's on the OEM long tracts, and cams dialed in to the factory settings.

I did the same as you to eliminate all the suspects: fuel lines, heatshield wrapping and rerouting, new fuel filter, clean gas, manual petcock, new vacuum line, etc.

time to go flip through a 'lectric pump catalog or try rebuilding the older pentagon shaped one to see if I can solve the problem with it.