10-03-2009, 02:22 PM #1
- Join Date
- Jun 2009
pop off pressure on Keihin carbs, what am I missing?
Well, because the kawasaki 1995 STS 750 with new SBT motor seems to be missing some acceleration, I have gone back into the stock keihin carbs and am trying to check pop off pressure. I have new kits installed from SBT, most notable in that they have metal instead of the rubber tips that came out of the carb in what I believe is the stock set up.
I am using a Harbor Freight cylinder leakdown tester which seems perfect for the leakdown test, since it has a pressure regulator that I can slowly twist up the pressure until the needle pops. I have double checked its reading against another pressure gauge, and both are close. I have also done a 1996 Polaris slt 700 with essentially the same kits and carbs.
Here is my issue: Both sets of carbs tested out to about 36 psi on the pop off pressure, and both call for 20 to 24 psi.
I am pretty sure the carbs are stock, it does not make sense that both had higher, but identical pop off pressures and springs-makes me suspicious of my means of testing, or something else.
I did change out the springs on the Polaris 700 to the weakest springs in the SBT carb kit to get into the 20 to 24 psi range, and it runs great but seems very rich on the low end, and acts sorta loaded up until I get over 2500 rpm or so, then it takes off like a rocket. adjusting the low speed adjusters down seemed to help, but still acts loaded, until it takes off and goes, so I am suspicious I may have the pop off pressure too low on it. Thanks for any comments.
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