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Old 06-22-2008, 01:12 PM   #1
jmclau74
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Default 93 virago 750 carb issues

Hello all,

I've been having issues with my 93 virago 750. First the gas was getting into the crankcase, so I rebuilt and cleaned out the carbs. Found some nice junk behing both jets but everything else seems clean. Replaced all parts that came in the kits.No tears in diaphrams in carb,no external fuel leaking. Adjusted valves with feeler guage to spec, adjusted carb syncro screw by ear to best of my ability, idles and starts great, loss of power and breaks up with load on it,(while riding). I can rev it up standing still and no indication of loss of power. Compression is even on both cylanders, about 150. Any ideas where I should go next? Note...I'm still testing and watching closley to see if fuel is still going into crank...I've had this issue for a while and continue to try different things and change the oil as I find it has fuel in it....please help!!!
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Old 06-22-2008, 06:31 PM   #2
The_AirHawk
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Sounds like spooge in a line, elbow, tee, filter - something like that. Does this model have those tiny "filters" in the carb inlet? What about the petschlong - is it vacuum-operated on this model, and are you certain it's opening all the way?

Just a few things you may or may not have thought of.
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Old 06-22-2008, 06:42 PM   #3
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If gas is getting into the crankcase, you have a bad over-rich condition that will dilute the oil film off the pistons/cylinder wall and eventually ruin the top end. Check your needle in the float bowl, sounds like it way too rich (float level too high).
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Old 06-22-2008, 06:54 PM   #4
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I was assuming the gas in the oil was caused by a stuck float (as he'd said something about spooge in the jets) when it was parked, but that's also something to check - having had them apart, sometimes you can bend a float out of adjustment.

Either way, hope it's something simple.



Oh hey! Does this bike have a fuel pump? Is it pumping, and pumping enough fuel if so?
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Old 06-23-2008, 05:07 AM   #5
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Floats aren't sticking?

Power loss could also be an ignition timing/advance issue.
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Old 06-23-2008, 01:30 PM   #6
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PS bike is fed from vacuum or gravity in prime...no fuel pump. Thanks.
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Old 06-23-2008, 01:34 PM   #7
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I also did the float test with the clear hose connected to the port on the bowl, opened the screw and the level appears to be in range on both....I think it was OK it was about half or a little over half way up the bowl on both carbs... does that sound right?
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Old 06-23-2008, 02:32 PM   #8
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Thanks to all for replying....As for the filters there are none, and I rebuilt the pet-****, it is working properly. It has three positions, prime, reserve and fuel. It is vacuum controlled and in prime it dumps fuel as intended and in reserve and fuel (Normal) it does not drop fuel unless its pulling vacuum from the engine. All lines were cleaned out and the screen cleaned on the pickup. At this point I start up better and easier than ever before(owned the bike for 7 years), it when I put a load (Riding) that it loses power at 2500 RPM's. If there is no load I can rev it up to 6,000 with no breakup. All RPM ranges are solid sounding on the kickstand. It may be ignition or something but I'm not sure how to test that...any ideas or info on troubleshooting based on symptoms I've given. Thanks for all the help...I'm stuck right now.
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Old 06-23-2008, 02:36 PM   #9
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PS bike is fed from vacuum or gravity in prime...no fuel pump. Thanks.
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