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tom loomes - n/a
14-Feb-08, 09:39 AM
Im currently working on a racing hovercraft using a honda cb500 twin cylinder motorbike engine, but we need a fuel pump which a cb500 doesnt have as the fuel is gravity fed.

I was wondering if anyone knows of a suitable fuel pump that could be used and also how it would fit on the standard wiring loom which i have.

Also how much would a pump cost?



Any suggestions and furthur information would be much appreciated

Thanks



Loomesy

jon_curtis - n/a
14-Feb-08, 11:45 AM
there are all sorts of electric fuel pumps out there! some are adjustable flow/pressure, generally as i understand you just need power to it, pos neg. but steady voltage/current so you will need a small bike battery, if there is not already one on your craft!



I fitted a fuel pump for the lift engine on my sev, it was off ebay, cost five quid, was off a 600cc bike, zx or zr or something like that! i was worried it would pump too much fuel, and blow out the needle valve in the carb bowl, but it just pumps as much fuel as the engine needs and was cheap!



I have a two way lanyard switch, which has break to make and make to break contacts on the back, when i put the lanyard on, its starts the pump and takes the ignition off ground, pulling off, cuts the pump and makes the shorting cable to ground.





hope this helps



jon

hovmart - n/a
14-Feb-08, 11:45 AM
why not use the Briggs & Stratton 35hp pump, it runs of the pulses from the crank case pressure, no wireing, they are cheap 20 ish. from any B&S agent

jon_curtis - n/a
14-Feb-08, 11:48 AM
dont think that will work with a cb500 four stroke?

hovmart - n/a
14-Feb-08, 12:12 PM
why not?

hovmart - n/a
14-Feb-08, 12:17 PM
the B&S is a 1000cc 4 twin four stroke works all right on it, using an electric pump is a bit like cracking a wallnut with a sledge hammer, sorry if you spent all that time wiring up and needing batterys when a maintaince fee pulse pump would have done the job better http://hovercraft.org.uk/images/icons/smiley_icons/icon_razz.gif

tonybroad - n/a
14-Feb-08, 04:02 PM
the small mikuni vacuum pumps are superb and deliver enough for a thirsty, big jetted TZR250 on full chat for 10 minutes (which is about 5-6 litres of fuel) plenty for a CBR500 - fit two if you're unsure



you can pick them up for 20 ish and service kits are about 6 - i change the membrane once a season to be sure



http://www.zipnorth.com/index.php?main_page=index&cPath= (http://www.zipnorth.com/index.php?main_page=index&cPath=34_77) 34_77



the gearbox one is a greater capacity

bryan - n/a
14-Feb-08, 04:50 PM
I have built and raced craft with 4 strokes and have had great success using bike fuel pumps.From Yamaha FZR 250 600,Honda vrf 400 pumps have all worked well.

jon_curtis - n/a
14-Feb-08, 06:25 PM
using an electric pump is a bit like cracking a wallnut with a sledge hammer, sorry if you spent all that time wiring up and needing batterys when a maintaince fee pulse pump would have done the job better http://hovercraft.org.uk/images/icons/smiley_icons/icon_razz.gif




why is it like cracking a nut with a sledge hammer? please explain?



My lift engine has no crank pulse outlet! in the lawn tractor it was gravity fed! so why would i consider drilling a hole in the crank? over a fuel pump i had in my shed! as for needing a battery, how else am i going power the lights, gps,radio etc



i might be totally wrong but the cb engine is wet bottom end, wet cutch etc! where would you put the pulse outlet that wouldnt p1ss pressurised oil out? same goes for a briggs engine, haveing a designed in pulse outlet, outside of the oil flow area, i wouldnt be happy drilling a hole in the crank!



2 strokes are a slightly different matter however and i can see why a converted tzr user would put such a pump on, after microlight engines use them, and they are light simple and reliable!



cant help feeling the later part of your message is ment to be a little provocative? thought the forum was on the up, but it appears not http://hovercraft.org.uk/images/icons/smiley_icons/icon_sad.gif there's no need to put a dig in martin, after all you no nothing of the build and requirements of my craft!



for the record im not having a dig back at you, just tryin to explain and expand so others understand why i siad what i posted early! http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif

sixpackpert - n/a
14-Feb-08, 06:58 PM
Im currently working on a racing hovercraft using a honda cb500 twin cylinder motorbike engine, but we need a fuel pump which a cb500 doesnt have as the fuel is gravity fed.

I was wondering if anyone knows of a suitable fuel pump that could be used and also how it would fit on the standard wiring loom which i have.

Also how much would a pump cost?



Any suggestions and furthur information would be much appreciated

Thanks



Loomesy






The Goldneys ran a cb500 in F3 a while back I am sure they had an electric fuel pump on it. I will have a chat with them at the AGM and let you know what their setup was if you like.

team black - n/a
14-Feb-08, 09:27 PM
The crank rebreather tube, or tapped off of the head are the obvious places to fit a pulse pump, if that's what you want to do.



Personally I'd go to somewhere like Demon Tweaks and buy the cheapest Facet fuel pump and get the adjustable diaphragm regulator. Plumb it all in and get the engine running. Wind the regulator open till fuel runs out of the carbs at revs, then wind it back till it stops. This system worked for me for many years on a number of craft.

hoverchaps - n/a
14-Feb-08, 09:30 PM
There are many ways of using different fuel pumps as all engines 2 or 4 stroke can use inlet or crankcase pressure. Elec pumps are fine, and there are available mechanical fuel pressure regs, i had one on the 400 4 honda, no probs at all but dont use a fuel pump from a fuel injected motor as they run at 3 or 4 bar.



I hope that sorts out the problem and is a good thing to know there is someone else using a 4 stroke lump.

tom loomes - n/a
14-Feb-08, 10:45 PM
Thanks for the swift responses

To be honest i thought id be p**sing in the wind so to speak with this little conundrum but theres enough here to ponder (keep 'em coming though because its all good)



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The Goldneys ran a cb500 in F3 a while back I am sure they had an electric fuel pump on it. I will have a chat with them at the AGM and let you know what their setup was if you like.
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That would be great, thanks very much, in fact do they have an email address so i could contact them directly (if they dont mind)



Thanks again for the help and advice



Loomesy

tom loomes - n/a
15-Feb-08, 11:19 AM
My lecturer suggested this, would it be appropriate?



http://www.minispares.com/Product.aspx?pid=34645



Thanks

Nick Long - n/a
15-Feb-08, 11:46 AM
Not the SU electric fuel pump. Its the work of the devil, the most fiendish device ever invented for stopping motor cars. It also weighs half a ton.



If you want an electric pump, then for less money and a fraction of the size and weight, you can get a solid state Facet cube pump.



Nick

HAVERCRAFT - n/a
15-Feb-08, 04:09 PM
Ok, for what it’s worth my advice would be not to use a facet or a second hand bike pump, but to buy a new electronic pump like e-bay item no 360024153560



I have based this advice on racing a 4 stroke in F3 since 2003, but if you want to go with the facet I have one that has hardly been used and would sell it to you very cheap!!!



Fred Wilson