MS'ing 45 degree V-Twin

[Dr.Hess]

Hey Guys,
I've been working on collecting parts for the MS 883. The Buell fuel pump I bought is an intank, as correctly spotted above, and while I could make a little mini tank to mount it in, I'd really rather have an external. Which brings me to my research. It turns out, near as I can figger, that a Polaris Victory V92C is fuel injected with an external fuel pump. Here's a picture:


So I bought the one above for $21. I figure that it should have low draw, be small and have enough HP for a bike, as it was on a bike. The GPZ 1100 also has an external fuel pump, but I think those are less common than the Polaris. At least on eBay.

Also, a guy on my Locost list has a FP collection and he looked at some small pumps for me. He found three small pump and checked the no load (dry) current draw. Results were:

Carter 2A
Walboro 1.8A
Bosch .7A

I don't know what they went to. The Walboro was an intank, but the carter and bosch are externals. The Bosch has hose barb connections, and the Carter has female threads. The Bosch is also more expensive. He sent me some pics, and they are all pretty small.

Anyway, I think that between the Polaris pump I just bought and maybe the Bosch or Carter, I should be good to go on a fuel pump.

Just passing on the info in case some of you guys are still looking for a pump.

[newtyres1]

Dr. Hess,

That's pretty good (the current draw), the XB Buell's internal fuel pump draws 4.75A, measured on my bike without the engine running.

Edit - oops, I missed the point that those are 'no load' figures...

Ian.

[Dr.Hess]

Mark says the Bosch is likely not made anymore, so that would make finding a replacement a bit challenging. He says "The Carter pump was part of a marine EFI setup. Probably a V-8 from a Merc or OMC."

[FIntruder]

You da man Dr. Hess! I waited to reply to this thread until after I won the pump on Ebay, sorry, didn't wanna create any extra competition. It looks like it could be the answer, the missing link, the ying for our yang!
Do you have one in yer posession yet? Do you know what it draws with fluid running through it, not dry? If it draws close to 5 amps then maybe any FI pump is gonna draw that much and we will just have to live with it. Like having another headlight on all the time. My bike has a big brother 1500 model that has a higher output charging system and I can always go to that if need be. It may work just fine the way it is.

So do we know for sure if the pump will draw more under load? With less load? I figured it would draw a constant amount and not react or compensate for load.

[Dr.Hess]

I don't have my Polaris pump yet. Just finished the auction 3 days ago. Hopefully it got shipped yesterday.

Those numbers from Mark were dry and not the Polaris pump. He said to add 50% as a rough guestimate for under load.

I'm going to guess that these pumps are fairly constant current wise, but I'm just guessing. The regulator is going to dump excess fuel back to the tank if it doesn't need to go to the injectors, so I would guess that the flow rate at the pump itself is going to be somewhat steady.

So, which one did you buy? Post a link.

[FIntruder]

Looks just like your pic, pump with hose and filter. The V92C should be very close to the output of my Intruder so should work as well as anything else. I'm gonna check Ebay for V92C throttlebodies to see what they look like, maybe I'll use those too instead of the X1 Lightning body I have already.

[Dr.Hess]

OK, I know which one you got. I had it Watched in case I didn't win the auction on the one I got. I had to snipe that one, too. Looks like they went for about the same price. I think we did good.

I really don't know anything about Polaris bikes. Actually, I don't know much about non Harley bikes when it comes down to it. Some Triumph stuff. Anyway, I had to do a bit of surfing/research to find that V92C model, but I think the fuel pump should work out for us. There are only so many GPZ 1100's out there, and the one on eBay was starting at fifty BIN for $75.

Next up: Fuel Pressure Regulator. This is what I'm thinking: Get an automotive unit from a fuel rail off a common EFI motor. Make a fitting to match whatever it is that attaches it to the fuel rail. Hose barb that fitting to a T going to the injectors. Excess pressure from the regulator back to the tank or to a T on the input side of the fuel pump.

[Dr.Hess]

Got my FP today! Woo hoo. OAL barb to barb is about 8", and it is about 1.75" diameter. Pretty small, I'd say. It is a Walbro, Made in USA.

What are people doing for high pressure filters after the pump? I have the OEM one on my Toyotas, but for the bike, are people doing without or putting something small in there?

[FIntruder]

I purchased a Purolator fuel filter years ago, as long as it is all steel I think it can handle the pressure.
You should look for an adjustable Fuel Pressure Regulator, most use hosebarbs and are pretty small. I think modding an OEM regulator would be alotta work and then you are stuck with the pressure it is set for.
What is the size of the hose barb(s) on the pump? Mine is coming from Georgia so I should have it soon being in Florida.

[Dr.Hess]

The hoses look to be standard 3/8" stuff. I didn't take them apart to look. Slight chance they are 5/16", but I dont' think so. The filter in the pic is actually on the output side of the pump. I'll probably just hook it up backwards to backflush it, then re-use it. Even got 4 or 5 nice little worm gear clamps. Heck, that's five bucks at the auto part store.

I'll look around for an adjustable FPR. The fixed pressure should be OK, as most EFI systems run about 46 PSI, I think, and with the MS, we can set the map to whatever we want anyway. But, the 883 doesn't need much gas at idle/cruise (we have gotten over 90MPG consistantly in the mountains when we had the stock carb on it) so the pulsewidth is pretty low, and these Buell injectors are for a bigger motor too. A lower pressure will let me increase the pulsewidth some if I need to.