trickedcarbine Posted January 18, 2011 Report Share Posted January 18, 2011 Ok, I run an oval bike currently with a 4mm stock cylinder motor that produces about 80hp. The issue is after about 2/3 laps the bike begins to show signs of leaning out. (gets hot, popping, etc.) I rode the bike down open dirt roads to get the tune up on jetting right, but once I put it under full load on the ovals it just seems to run out of fuel. I had slight issues last year with my stock stroke motor and remedied the problem with a dual pinguel. I even tried to up jetting on the main and needle but it ran like pig, and just fouled plugs. So it is pretty apparrent that the bowls are going dry. Now comes the new dilema of how to get this motor fed the fuel it needs. I thought about just sticking bigger bowls on it, but I think it would be a waste to spend the money on carbs I will problably not be running in a few months when a twister top end finally goes on. So I remembered I have an old 440 snomobile that my buddy bought a pump for and it is still in the box. I think that since I will definitely be needing a fuel pump on the new motor in a few months I might as well get it on the bike now. I know that I need to tap the cylinder right in front of the reed cage to get the pulse signal, but does any one have an idea on how I go about the return system? Do I just plumb the overflows together from both carbs and run it to a bung on my tank? Also, should I get a regulator to run with the pump? Quote Link to comment Share on other sites More sharing options...
shanYE west Posted January 18, 2011 Report Share Posted January 18, 2011 Ok, I run an oval bike currently with a 4mm stock cylinder motor that produces about 80hp. The issue is after about 2/3 laps the bike begins to show signs of leaning out. (gets hot, popping, etc.) I rode the bike down open dirt roads to get the tune up on jetting right, but once I put it under full load on the ovals it just seems to run out of fuel. I had slight issues last year with my stock stroke motor and remedied the problem with a dual pinguel. I even tried to up jetting on the main and needle but it ran like pig, and just fouled plugs. So it is pretty apparrent that the bowls are going dry. Now comes the new dilema of how to get this motor fed the fuel it needs. I thought about just sticking bigger bowls on it, but I think it would be a waste to spend the money on carbs I will problably not be running in a few months when a twister top end finally goes on. So I remembered I have an old 440 snomobile that my buddy bought a pump for and it is still in the box. I think that since I will definitely be needing a fuel pump on the new motor in a few months I might as well get it on the bike now. I know that I need to tap the cylinder right in front of the reed cage to get the pulse signal, but does any one have an idea on how I go about the return system? Do I just plumb the overflows together from both carbs and run it to a bung on my tank? Also, should I get a regulator to run with the pump? All you do is run fuel into the pump.. then depending on what model pump you get.. you either run one line to your carbs with a T.. or 2 lines (one to each) then the pulse line. Quote Link to comment Share on other sites More sharing options...
Starwriter Posted January 18, 2011 Report Share Posted January 18, 2011 Make sure your gas tank vent is allowing enough air in for the amount of gas that's flowing out. Run the fuel lines into a container and open the valve. See if the fuel flow slows down after a bit. If so, then crack open the gas cap and see if it flows again. Quote Link to comment Share on other sites More sharing options...
badassbanshee479 Posted January 18, 2011 Report Share Posted January 18, 2011 pumper carbs have a smaller needle and seat.... your gravity carbs have a larger needle and seat... setting the float height and keeping the carbs from over flowing with a pump on non pumper carbs can be a real pita! I would skip the pump and just cut one float off in ea carb... that will give ya more fuel. I also pull the check valve out of the gas cap and drill the hole as big as ya can get it and still be able to get the vent line on it...... I do these two mods to the alky carbs and or bikes I set up and we never have any issues with running out of fuel. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted January 18, 2011 Report Share Posted January 18, 2011 Maybe check with carb parts warehouse, they should be able to steer you in the right dirrection. Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted January 18, 2011 Report Share Posted January 18, 2011 like mentioned above.....try gutting your gas cap. Jeff at FAST just had me do that just to be safe after i got my cylinders back from him. There's 3 screws on the inside and you can just take the screws out and lose EVERYTHING that comes out....and you dont have to put any of the crap back on.....Jeff said he wanted me to gut it so that you could see from one side to the other side. This might clear up your problem......if it doesn't totally hellp then it might be time for a pengel also.... Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted January 18, 2011 Author Report Share Posted January 18, 2011 Hey, thanks fellas. I appreciate the help. Gutted the gas cap right before posting the topic, so I hope it helps. Some people just don't believe how much fuel a flat track bike will use. We are pretty much hot lap drag racing for 40 runs straight, plus there is the almost wide open throttle turns inbetween. I guess it is time to pony up and just get this pump situation sorted. Any one know who to contact about proper needle and seat for use with a pump? Quote Link to comment Share on other sites More sharing options...
Duke 2 Stroke Posted February 1, 2020 Report Share Posted February 1, 2020 Hey did you ever figure out the fuel pump issue? Quote Link to comment Share on other sites More sharing options...
Deets Posted February 2, 2020 Report Share Posted February 2, 2020 14 hours ago, Duke 2 Stroke said: Hey did you ever figure out the fuel pump issue? You know this thread is 9 years old?? 1 Quote Link to comment Share on other sites More sharing options...
Duke 2 Stroke Posted February 11, 2020 Report Share Posted February 11, 2020 Yes but I was trying to find out is there a certain fuel pump with certain amount of psi I need to look for Quote Link to comment Share on other sites More sharing options...
OneBADBanshee05 Posted February 12, 2020 Report Share Posted February 12, 2020 There’s a whole lot of stuff that comes into play when trying to achieve this ideal and some is good and some is not so good. Yes, the psi is very important roll. You would also have to install some kind of fuel pressure regulator because If there’s to much psi then your taking a chance of either blowing up your carbs and turning your banshee into a rolling fireball or the pump would dump unused fuel into the engine at lower rpm’s which would cause the unused fuel to either hydro lock the engine or it would wash the crankshaft bearings out. You would have to almost design something like a EFI system which would have to work off of an ECM which would have to control the timing of spark and fuel pulse. If I was trying to achieve something like this I would experiment with a windshield washer fluid pump at first to see if the pump would work with gasoline and how long it would continue to work. You would have to design or hook up a secondary fuel on /off switch. If the windshield washer fluid pump would work I would see if it would work off of the lighting system on the banshee where if you are just riding around you don’t used it and while under on the track using high rpm’s you could just flip the headlight switch on and it would pump extra fuel to the carbs. It’s just a real touchy situation trying to achieve this goal. It’s a trial and error type of thing. Just my $0.02 1 Quote Link to comment Share on other sites More sharing options...
OneBADBanshee05 Posted February 12, 2020 Report Share Posted February 12, 2020 I forgot to mention that you could also contact Duncan Racing and talk with them because they are known for building race winning banshee’s that have raced TT/ Flat Track, Pikes Peak and Both Baja Race’s. Quote Link to comment Share on other sites More sharing options...
specialblend07 Posted February 12, 2020 Report Share Posted February 12, 2020 There’s a whole lot of stuff that comes into play when trying to achieve this ideal and some is good and some is not so good. Yes, the psi is very important roll. You would also have to install some kind of fuel pressure regulator because If there’s to much psi then your taking a chance of either blowing up your carbs and turning your banshee into a rolling fireball or the pump would dump unused fuel into the engine at lower rpm’s which would cause the unused fuel to either hydro lock the engine or it would wash the crankshaft bearings out. You would have to almost design something like a EFI system which would have to work off of an ECM which would have to control the timing of spark and fuel pulse. If I was trying to achieve something like this I would experiment with a windshield washer fluid pump at first to see if the pump would work with gasoline and how long it would continue to work. You would have to design or hook up a secondary fuel on /off switch. If the windshield washer fluid pump would work I would see if it would work off of the lighting system on the banshee where if you are just riding around you don’t used it and while under on the track using high rpm’s you could just flip the headlight switch on and it would pump extra fuel to the carbs. It’s just a real touchy situation trying to achieve this goal. It’s a trial and error type of thing. Just my $0.02 What in the tarnation? Putting a fuel pump on a banshee is about as easy as tying your shoes. Also, your advice on calling Duncan isn’t good. Stay away from them. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
specialblend07 Posted February 12, 2020 Report Share Posted February 12, 2020 Hey did you ever figure out the fuel pump issue?Buy a Mikuni fuel pump. Don’t listen to the other guy rambling. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Duke 2 Stroke Posted February 15, 2020 Report Share Posted February 15, 2020 On 2/12/2020 at 4:58 AM, OneBADBanshee05 said: There’s a whole lot of stuff that comes into play when trying to achieve this ideal and some is good and some is not so good. Yes, the psi is very important roll. You would also have to install some kind of fuel pressure regulator because If there’s to much psi then your taking a chance of either blowing up your carbs and turning your banshee into a rolling fireball or the pump would dump unused fuel into the engine at lower rpm’s which would cause the unused fuel to either hydro lock the engine or it would wash the crankshaft bearings out. You would have to almost design something like a EFI system which would have to work off of an ECM which would have to control the timing of spark and fuel pulse. If I was trying to achieve something like this I would experiment with a windshield washer fluid pump at first to see if the pump would work with gasoline and how long it would continue to work. You would have to design or hook up a secondary fuel on /off switch. If the windshield washer fluid pump would work I would see if it would work off of the lighting system on the banshee where if you are just riding around you don’t used it and while under on the track using high rpm’s you could just flip the headlight switch on and it would pump extra fuel to the carbs. It’s just a real touchy situation trying to achieve this goal. It’s a trial and error type of thing. Just my $0.02 That was some very good advice and knowledge you shared there brother. Thanks for the advice and I will definitely look more into this before I think about attempting this. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.