Fuel Pressure? - Kawasaki ATV Forum
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post #1 of 7 Old 04-06-2007, 04:00 PM Thread Starter
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Anyone actually stick a gauge on their V to see what the pump puts out? I have been having some top end issues that seem as if the bike is starving for fuel. I have went up one size on the pilots, and I am at 198/200 on the mains. All I have is a Muzzy, and the 36's. With my old bike (same engine) and my prototype intake, I was getting around 8400 RPM's through a modded slip on. Now, I am playing hell to get it to 8K, without the intake, and a better (assumed) exhaust. It revs to around 7000-7100 and upshifts at that RPM, upon shift out, it hits about 7500, and starts to break up. I have a constant 2.5 PSI of fuel pressure from idle to shift out. It's kinda hard to see exactly due to vibration, but it is over 2PSI under WOT. Now, somewhere near when it shifts out, and it overrevs, it begins to drop. I am guessing it is only seeing 1.25- 1.5PSI of pressure. Just curious if this is normal with the engine RPM increasing, or not.

I know I free revved the engine in the garage, and held it to 8K for awhile to see if it would drop the fuel pressure, and it didn't. No breaking up, nothing. I changed the battery, plugs twice, CDI, double checked the intake boots, and there is nothing there. Only thing I can think of at this point is either the fuel pump, or coil packs.

Any ideas?

I just bought a FAST dual Wideband, and it will be here next week, but I was gonna hit the dragstrip this weekend, and don't feel like wasting my time with it running the way it is.
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post #2 of 7 Old 04-06-2007, 04:21 PM
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I had simial fuel issues, I pulled the pump and did away with the check valve. Gave me a more volume, but no more pressure. Mine seemed to run out of fuel at wot for any amount of time.

pull the pump, pull the hoses and back flow valve, off at the bottom of the pump, and replace with a longer (6" or so hose). 10 minute job if you can get at your pump.

Let us know on the new FAST widband, I think that would be the ticket.

PS, I finally went with a 3--5 psi pump that goes to a VW, one that didn't need a reg.


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post #3 of 7 Old 04-06-2007, 05:14 PM Thread Starter
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I'll swap pumps in the morning, and see if it fixes it. If so, I will mod the original pump, and see if it is enough to keep up. I just find it hard to believe that it is sucking the bowls dry. I pulled the choke on one trip down the road, and it didn't help, telling me that there was no more fuel to be had....
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post #4 of 7 Old 04-06-2007, 06:33 PM
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Quote:
I'll swap pumps in the morning, and see if it fixes it. If so, I will mod the original pump, and see if it is enough to keep up. I just find it hard to believe that it is sucking the bowls dry. I pulled the choke on one trip down the road, and it didn't help, telling me that there was no more fuel to be had....
[/b]
hell if it works for mine!
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post #5 of 7 Old 04-08-2007, 09:04 AM
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you already mentioned it but just a ditto for you on the coils being a possibility...



cdi would have been my very first choice but you already switched that. good luck

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post #6 of 7 Old 04-08-2007, 01:09 PM
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I went to the track last weekend and same thing,Breaking up Big Time man,it was my intakes.I have 36s also and I took the plastic off the bike and started it up and sprayed fogging oil around the bottom of the carbs and there it was Smokeing!!!So my intake was the problem the hole time and I went threw everything at the track that day and was Stumped man,so just double check it,may be worth trying.Also my stock pump puts out almost 3 PSI and I tapped in to the gas line for the NOS pump and I was told it would not work like that but it does and fine,its not leaning out at all and made it easier but I am getting a tank bung this week and it has a screen made on it and you drill a hole in the tank and put the bung in and run the NOS fuel pump from there,but from the stock line it is at 7 1/2 PSI even at 90 MPH it doesnt drop and it keeps the motor zinging and this is with a 24 Shot..I would like to do the stock pump mode,what all has to be done?????


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post #7 of 7 Old 04-08-2007, 01:51 PM Thread Starter
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I was just too rich, I jetted back down almost to my initial start point, and it is now lean, but it doesn't lose pressure, and I had it to 8400 down the road Saturday with no breaking up.
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