i got a 2000 ish reactor kart chassis, i'm going to put a 2007 rmz450 motor on it and make it a shifter kart, my only delema is idk how im going to get the fuel from the tank under the steering stem to the carb, i dont know what kinda fuel pump i will need, an electric one might flow to much, and i wont have 12vts to power it. any help will be greatly appreciated
Fuel pump
- Thread starter irunktm
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anderkart
Moderator
Karts like yours use pulse fuel pumps:-->http://www.amazon.com/Fox-Distributing-DF52-21-D-Mikuni-Double/dp/B00336EBHQ/ref=pd_sbs_auto19
No 12-volt needed, they work by connecting a 1/4" hose to a fitting in your intake manifold.
No 12-volt needed, they work by connecting a 1/4" hose to a fitting in your intake manifold.
ok, i was thinking a pulse pump but i wasnt sure how that would work on 4 stroke, 2 stroke you put the fiting in the crank case. on that motor where would i put the pump fitting to pust enough air to spin the pump? my other idea was put a electric pump just like if it were gunna be a strait run to the carb, but put a small, 5-10 floz gas tank above the carb with a float switch in it, the pump fills up the small tank, then the float shuts off the pump till it needs more fuel. that would kinda be a pain, pulse pump would be easier. so i guess my question is where would i put the fitting in the motor?
ok, i was thinking a pulse pump but i wasnt sure how that would work on 4 stroke, 2 stroke you put the fiting in the crank case. on that motor where would i put the pump fitting to pust enough air to spin the pump? my other idea was put a electric pump just like if it were gunna be a strait run to the carb, but put a small, 5-10 floz gas tank above the carb with a float switch in it, the pump fills up the small tank, then the float shuts off the pump till it needs more fuel. that would kinda be a pain, pulse pump would be easier. so i guess my question is where would i put the fitting in the motor?
anderkart
Moderator
Some 4-cycle motorcycle engines already have a small barbed-fitting installed between the carb and head, or could easily have one installed to operate a pulse pump.
You can run a pulse pump off the crankcase of a 4-cycle same as a 2-cycle. That's how I've got it set up on my 4-cycle kart engine.
Here's a pic of my setup:
(that's my round Mikuni pulse pump bolted to the front of the engine, the short 4" line coming off the right side of my pump connects to a fitting drilled/installed in the crankcase)
You can run a pulse pump off the crankcase of a 4-cycle same as a 2-cycle. That's how I've got it set up on my 4-cycle kart engine.
Here's a pic of my setup:
(that's my round Mikuni pulse pump bolted to the front of the engine, the short 4" line coming off the right side of my pump connects to a fitting drilled/installed in the crankcase)
Anderkart, what's the advantage of installing a fuel pump over the stock gravity system? I don't race, but my engine is very similar to a clone superbox engine minus the carb. I just have a bored out stock carb. Is it worth it to install a fuel pump?
anderkart
Moderator
Tony, most racekarts have they're fuel tanks mounted up front for safety/fire reasons and to transfer a few lbs. of weight to the center of the chassis/front tires. This also keeps the fuel cooler than an fuel tank bolted to a hot engine, so it could also offer a bit of a performance advantage.
anderkart
Moderator
I just cap off the secondary outlet. I could use a square pulse pump but I've had better luck with the large round Mikuni pumps lasting a long time without any problems.
anderkart
Moderator
Yeah you can buy a 1/4" Barbed Fitting like this pic at a hardware store:
(I used red locktite on the threads)
(I used red locktite on the threads)
ok, i picked one up today, i got a lotta work ahead, Idk if you have any experence with 4 stroke race dirt bike motors but idk where to put this fitting in, the carb boot is rubber and would probably tear, there isnt much room in the crank case, and where there is room its blocked by the timing changing. is it possible to put it in the valve cover, is there any pressure differences up there
mckutzy
Well-known member
on this site they describe just that and how to for a fuel pump.
http://www.affordablegokarts.com/fuel-pump-setup.php
http://www.affordablegokarts.com/fuel-pump-setup.php
anderkart
Moderator
You'll get the strongest pulse signal from the the intake. you can buy a nut and washers to fit those 1/4" barbed fittings. That along with some locktite on the threads and maybe some silicone gasket sealer to help it all make a perfect seal would be the method I'd use.
If you bought thin-brass washers you could bend them to better conform to the round shape of your round-rubber intake. Then the silicone would further help make a seal.
Pulse fittings in the crankcase or valve cover can work fine too, but they'll always give a weaker signal. Also, depending on how much oil is splashing around where you instal the fitting, you can also run into issues with drawing oil into the pulse line and pump, and this can greatly lower the performance of pulse pumps.
I'd go with the intake manifold method, just make dam sure that nut inside cant ever loosen up and get sucked into your engine. You might double-nut it, plus use locktite...
If you bought thin-brass washers you could bend them to better conform to the round shape of your round-rubber intake. Then the silicone would further help make a seal.
Pulse fittings in the crankcase or valve cover can work fine too, but they'll always give a weaker signal. Also, depending on how much oil is splashing around where you instal the fitting, you can also run into issues with drawing oil into the pulse line and pump, and this can greatly lower the performance of pulse pumps.
I'd go with the intake manifold method, just make dam sure that nut inside cant ever loosen up and get sucked into your engine. You might double-nut it, plus use locktite...
anderkart
Moderator
Yeah, something else to keep in mind is the needle and seat valve in your carb is probably designed for a gravity flow fuel supply. Some of these work fine with the additional fuel pressure of using a fuel pump, but some develop flooding issues because they cant stop the flow. For some carb models, Mikuni sells a special needle and seat valve made for use with fuel pumps.
What kinda kart are you installing this engine on? Just simply mounting your fuel tank above the carb and gravity flowing the fuel might be an option to consider...
What kinda kart are you installing this engine on? Just simply mounting your fuel tank above the carb and gravity flowing the fuel might be an option to consider...
Yea, my biggest concern with a fuel pump is flooding, i can get a restrictor that limmits the pressure to about .5 psi, but i dont want to put a tank over the motor because it looks stupid, my only idea was put a small few ounce tank about the carb with a float level switch in it that ran the fuel pump on and off, so it would fill up the tank then gravity feed into the carb, it would be a real pain to have to do all that but o well
anderkart
Moderator
Another way to control fuel pressure reaching your carb is to to instal a return system to send the excess/unneeded fuel pressure back to the tank. I had problems with my carb flooding after i installed a pulse pump on one of my karts. Here's a pic of the fuel system I ended up running on my Beisse kart:
See that red knob near the back of the tank? That's my fuel return line. My pulse pump has dual outlets, one goes directly to the carb and the other is plumbed right back into the tank. I just installed an in-line fuel shutoff valve:--> http://www.amazon.com/Briggs-Stratton-698183-Shut-Off-Selected/dp/B0038U3JKM in my return line so I could adjust how much returns and ultimately how much volume/pressure actually reaches my carb.
That outer pulse pump line is the input. It's got an in-line filter, plus I installed a marine squeeze-bulb in-line to be able to prime the fuel system.
Here's a pic of my carb showing where I installed my pulse fitting.
I only had a 1/2" thick, hard plastic carb insulator to work with. So I pulled a 1/4" vacuum fitting out of an old car carburetor, (like the pic below) drilled a small hole in my carb insulator and epoxied it in place. Its worked fine for several years now.
You might try using a fitting from an old carb like this epoxied into a small hole in your rubber intake... This link shows the type of fitting I used: http://image.mustang50magazine.com/f/24280810+w750+st0/mump_0907_18_z+holley_4180+vacuum_port.jpg
See that red knob near the back of the tank? That's my fuel return line. My pulse pump has dual outlets, one goes directly to the carb and the other is plumbed right back into the tank. I just installed an in-line fuel shutoff valve:--> http://www.amazon.com/Briggs-Stratton-698183-Shut-Off-Selected/dp/B0038U3JKM in my return line so I could adjust how much returns and ultimately how much volume/pressure actually reaches my carb.
That outer pulse pump line is the input. It's got an in-line filter, plus I installed a marine squeeze-bulb in-line to be able to prime the fuel system.
Here's a pic of my carb showing where I installed my pulse fitting.
I only had a 1/2" thick, hard plastic carb insulator to work with. So I pulled a 1/4" vacuum fitting out of an old car carburetor, (like the pic below) drilled a small hole in my carb insulator and epoxied it in place. Its worked fine for several years now.
You might try using a fitting from an old carb like this epoxied into a small hole in your rubber intake... This link shows the type of fitting I used: http://image.mustang50magazine.com/f/24280810+w750+st0/mump_0907_18_z+holley_4180+vacuum_port.jpg
i see what you did, thats a good idea, i could get a y for after the fuel pump with a return like that, mabey that would work. and as for a pulse pump in the intake boot, there isnt enough room to put a pump fitting, theres mabey 1/8 in at best between the clamps, and theres no place to put the impulse pump.
anderkart
Moderator
Yes, you could use a Y-fitting in a single outlet pump, same thing.
If there's no room in your intake manifold, you could always instal a pulse fitting in the carb. Anywhere on the intake manifold side of the carbs slide/butterfly would work just the same as having a pulse fitting in the intake manifold...
You could always instal a pulse pump fitting in your valve cover, just try to find a location that doesn't have a lot of oil slinging around. Does your valve cover have a crankcase breather hose?
If there's no room in your intake manifold, you could always instal a pulse fitting in the carb. Anywhere on the intake manifold side of the carbs slide/butterfly would work just the same as having a pulse fitting in the intake manifold...
You could always instal a pulse pump fitting in your valve cover, just try to find a location that doesn't have a lot of oil slinging around. Does your valve cover have a crankcase breather hose?
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