When it rains it pours!

[sicivicdude]

Well, I gathered a few bits and pieces starting today. I bought a 1/8" NPT inline drain petcock with a nipple outlet (radiator draincock actually) not sure how I'm going to fit it in there or if the "wingnut" design is going to work out but it was cheap and most importantly, it's 100% brass construction so no rubber or plastic to eat out!

I cut to length a few piece of 3/8" round rod and through drilled them with a pilot hole. I plan on getting really long bowl screws and making these "tubes" three of the corners of the alky bowl.

Because of the clearance with the clutch arm, I'm going to have a "cut out" on the front left corner of the bowl that's basically the same size as the stock carb bowl (dimension wise) but the other three corners will be welded onto the outside of these tubes I drilled tonight as plate. Instead of the rounded bottom, it's going to be squared off and generally sloped towards the back where the drain petcock will be (hopefully able to bottom drain the bowl from the lowest point).

I'm also contemplating making a manifold. I have a UPP manifold for a 35mm carb and it just isn't large enough. The edge around the outer lip is cracked out from being stretched over this carburetor and I haven't even run it that much left. I have lots of pondering to do about this before I can lay out the next step to deal with that problem....

I have the fuel cell design traced out onto the aluminum sheet already so I can flip the welder over to the plasma cutter and chop the side pieces right on out in a jiff. Still take me a while to form the "wrap around" part but it won't be like designing from scratch again! I:I

I got the Pingle valve from 3mil yesterday. Completely awesome, it goes from a stopper to basically a 3/8" tube street elbow by turning the knob at the bottom. That valve can flow SOOOOO much fluid it's not even funny!

 

[Paulie B]

I wonder if you could install a one check valve into your stock bowl- at the level where your float would normally cut the fuel. Then just get a dual pingle, and run another line from your tank to the check valve.

 

[sicivicdude]

Wouldn't that just run constantly? I would need to key the headspace in the tank to the headspace in the carburetor bowl so that when the one way valve was covered in fuel it wouldn't siphon fuel down anymore.

If anything I could remove the fuel inlet assembly and manufacture a new needle with enormously outsized proportions. I've already ruined this carburetor for any "normal" use so what's to stop me from making a 5/16" fuel inlet hole and float needle to work?

 

[Paulie B]

Hmmmmmmmmm oversite lol
Have you thought about a good ol diaphragm pump?
They make them for sleds with 2,3, and 4 outputs. I can tell you from experience that it should go a whole season before the nitro starts getting to it.

 

[Paulie B]

Come to think of it more then 1 output would be a waste.

 

[sicivicdude]

Hmmmmmmmmm oversite lol
Have you thought about a good ol diaphragm pump?
They make them for sleds with 2,3, and 4 outputs. I can tell you from experience that it should go a whole season before the nitro starts getting to it.

Paulie, I'm using a Mikuni DF52 dual outlet snomo pump. That's what is overpressuring the float needle and flooding the carburetor.

One outlet was updrilled toa 3/8" tube and the other was left 1/4". The 1/4" line is a direct return to the tank while the 3/8" goes to the carburetor and it STILL overpressurized the carburetor.

 

[best]

Paulie, I'm using a Mikuni DF52 dual outlet snomo pump. That's what is overpressuring the float needle and flooding the carburetor.

One outlet was updrilled toa 3/8" tube and the other was left 1/4". The 1/4" line is a direct return to the tank while the 3/8" goes to the carburetor and it STILL overpressurized the carburetor.

I have never done too much experimenting with putting pumps on bike carbs, so I started asking around some of the sled and ski-jet guys.

Gravity feed carbs have a large inlet seat orifice and float needle that requires no more than 2psi.
Mikuni pumps typically put out 3-5psi and some up to 7psi.
They will overpower a gravity feed carb especially if the carb inlet has been drilled larger for alcohol (not sure if yours was).

Sled and jet-ski carbs are designed for these pressures.
They typically have one or more of these features:
smaller inlet seat orifice diameter
larger floats
longer float leverage arm or
a spring assist on the float needle.
built in regulator within the carb

I have a 94 Kawi that has en electric pump that only provides 2psi to the carbs.
Darned thing is at least 2 lbs and takes power. You don't want that...

 

[sicivicdude]

My research into the subject yielded about the same results. I figured a gravity fed carb couldn't handle much more than about 2 psi but that the pump could put out 4-5psi. That's why I put a bypass on the outlet of the pump to return it to the tank.

Obviously it still wasn't enough as the last time it ran, it spit fuel out of the bowl vents at me!

So back to the old standby, a gravity feed system.

I welded the top half of the fuel cell together last night. I have to do the bottom, bung, cap, and mounting tabs tonight. I'm going to attempt to run this thing on Sunday back over at my buddies house.

 

[Paulie B]

IDK where yalls info comes from but alky guys run pumps all the time?
My boy runs one on his LT250.
No matter sic seems to be gettin it done a different way now.

 

[sicivicdude]

IDK where yalls info comes from but alky guys run pumps all the time?
My boy runs one on his LT250.
No matter sic seems to be gettin it done a different way now.

If you get a carburetor setup for a fuel pump, you can run one to deliver the proper volume without an enlarged fuel bowl. They either have a smaller inlet hole, more leverage on the float needle, larger floats, or an internal pressure regulator.

I'm going to get it done gravity feed anyway...

 

[sicivicdude]

The fuel cell:

 

[sicivicdude]

Manifold:

CR125 reeds:

 

[scotj77]

lookin good!!!!!!!!!!!!!!!!!!

 

[sicivicdude]

Carburetor float bowl:

 

[Braaaptor]

Love it so far, James! I like the fact that the whole bike isn't all PC'd and chromed out like so many draggers out there. Nice to see a bike thats more 'go' than show. If ya have it running by Busco, I can't wait to see the look on guys' faces who have thousands of dollars in their bikes when they get beaten by this one. Lol

 

[gyzg921]

Lookin sweet so far.

 

[slickerthanyou]

Nice manifold, have been thinking on making one myself! Good work bro! HUGE BOWL!

 

[sicivicdude]

Nice manifold, have been thinking on making one myself! Good work bro! HUGE BOWL!

The manifold is actually just one piece of hand rolled aluminum tube snipped and bent into shape and then welded to a plate. I cut the 1/4" plate using my plasma and filed to shape. It's surprisingly easy to make, should have taken pictures of the processes of making these parts but was focused on getting them done, not documenting the process.

 

[slickerthanyou]

The manifold is actually just one piece of hand rolled aluminum tube snipped and bent into shape and then welded to a plate. I cut the 1/4" plate using my plasma and filed to shape. It's surprisingly easy to make, should have taken pictures of the processes of making these parts but was focused on getting them done, not documenting the process.

Looks do able! I may go stainless just to be different.

 

[Paulie B]

I love this project I:I