Miks15
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| posted on 18/4/11 at 09:17 PM |
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bike fuel pump questions
Hey guys,
I was just out working on the car. Im still having the same problems as before with my engine and bike carbs. Basically i have had the car running
with gravity feed so i know everything else works and that the carbs work. It is running on just edis at the minute, no megajolt or anything yet so a
fixed ignition point (10 degree BTDC IIRC).
But when running with the fuel pump (came off the same bike as the carbs, a gsxr600) and it wont fire up. If i disconnect the pump for and turn it
over it will fire up but not rev very well. So it seems the fuelling needs to be somewhere inbetween the bike pump and no pump. It seems very strange.
Today i disconnected the inlet in to the carbs and routed into a tub so i could check the flow. and here are my results:
It didnt flow smooth, more like a hand pump would, sort of in pulses.
It shifted about 30-40 liters and hour of fuel (filled just over half a liter in a minute).
Does this sound about right? When you connect it on the carbs you can hear the bowls filling up then stopping and its not then leaking anywhere so the
floats seem to be doing their jobs. Ive had the carbs off and cleaned it out, and checked the floats and bowls and all seemed fine.
Im a bit lost as to what to try next, any help would be much appreciated!
Cheers
Mikkel
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matt_gsxr
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| posted on 18/4/11 at 10:24 PM |
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That flow rate sounds a bit on the low side. According to the Suzuki manual the gsxr1000 k1 puts out 2.4litres per minute.
Is it one of those mitsubishi pumps? They are a bit wierd in that if you power them up backwards, then they work, but pump out less (although not
much less) than if you wire them correctly.
None of this really explains why it doesn't start though, as your flow is plenty for that.
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ReMan
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| posted on 18/4/11 at 10:30 PM |
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It all sound right.
Amount of fuel its pumping, stops when floats full, no leaks.
TBH I'd expect it to run correctly for a short while with full floats and no pump connected.
So it works and runs starts spot on with a gravity feed?
I cant imagine there is any feedback from the pump as your not using the bike ECU, so that rules that out.
Are you using an air box/filter at all, as that may have a bearing on the running, but otherwise I'd agree , very odd
www.plusnine.co.uk
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Miks15
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| posted on 19/4/11 at 07:54 AM |
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the k1 is fuel injection isnt it? which would probably explain why its over 4 times as much flow.
I dont have any air box or filter on it at the moment, the carbs are just open.
The pump has a grounded base so it can only be wired in one way.
yeh it just came to me that it would run without the pump because of the bowls being full which makes sense now. But i cant for the life of me work
out why it wont do it the bowls full and the pump running. Its frustating the crap out of me!
The only other thing is there is a another outlet on the bottom of the pump where, i believe, a vacuum hose goes. The outlet on the pump has a little
diaphragm and plunger inside which, i think anyway, restricts the flow, but opens up when the engine is running. But then this would surely restrict
the flow and it still seems like the carbs are over fuelling so it doesnt quite make sense.
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Miks15
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| posted on 19/4/11 at 05:24 PM |
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Ive just opened the carbs and there are no needles in them. No wonder they were over fuelling!
Does anyone know where i can get a set of needles and fittings for gsxr600 carbs?
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ReMan
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| posted on 19/4/11 at 08:19 PM |
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quote:
Originally posted by Miks15
Ive just opened the carbs and there are no needles in them. No wonder they were over fuelling!
Does anyone know where i can get a set of needles and fittings for gsxr600 carbs?
Well fancy no-one saying "are you sure your carbs are complete"
www.plusnine.co.uk
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Miks15
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| posted on 19/4/11 at 08:46 PM |
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well they looked to be complete! Its only when someone suggested adjusting the needles that i realised i couldnt when there arent any! ha
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matt_gsxr
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| posted on 20/4/11 at 08:47 PM |
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Sounds like you have found the problem
Flow rate from the pump still sounds a bit low to me. 1pint (uk pint, not a poxy US pint) per minute per 100bhp is a guide (though not necessarily a
reliable one).
EFI or carb the amount of fuel needed is about the same.
This will only show up at WOT and high RPM, so just look out for lean running on the AFR.
That should be enough TLA's for now.
Matt
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Miks15
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| posted on 20/4/11 at 11:12 PM |
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as for flow rate:
The pump has a diaphragm and plunger type thing inside the petcock which is controlled by a vacuum hose from the carbs. So when running at higher
revs, this plunger will pull out of the way opening up the outlet, and therefore more fuel i assume. So im not too worried about this.
Now just trying to hunt down a second hand set to get sent out tomorrow so it has some chance of getting here in the 3 day window next week!
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