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Discussion Starter #1
First off, hi there guys and gals.... hopefully you can help me... I recently started working in a very diverse motorcycle shop... basically we fix just about everything there is on wheels... please don't hold that against me. I'm usually not bad at figuring out "how it works" but this one has me stumped. And so does the one sitting right next to it. V-star 650 classic's both. So here's the issue. Florida has very horrible fuel sometimes... and people let their bikes sit... so we get em. "It wont run"... so we do the deal... clean the tank, clean the fuel pump, clean the lines, completely dissassemble the carbs, clean every millimeter of surface, then put it all back together... usually no problems from there. No float adjustment needed, good clean running bikes... So this particular duo of V-stars... Both run very well at idle while on the sidestand... but choke and puke when upright... slightly better with the choke pulled, but still not running right. Backfires, misses, and generally non riding... Pulled, cleaned, and adjusted the carbs so many times I can do it in my sleep, and I'm down about 4 cans of carb cleaner. Even ran them in our nifty little ultrasonic cleaning box... jets as well. I've seen a lot of posts about carb issues here, and on other forums... but none that mention this particular wierdness.... hope y'all can help me out. Thanks much in advance!
 

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Discussion Starter #2
B.t.w. They are both 650s, one is a 2000 one is a 2003. The 03 has stock pipes, the 00 has aftermarket straights, but they are both doing the same thing...
 

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Just tried putting a different set of spark plugs in... purely out of boredom... and it ran right for about 5 seconds, then started puking again... the other plugs are carbon fouled a bit... still at a loss... Gonna check compression, spark, etc. next I suppose.
 

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Just tried putting a different set of spark plugs in... purely out of boredom... and it ran right for about 5 seconds, then started puking again... the other plugs are carbon fouled a bit... still at a loss... Gonna check compression, spark, etc. next I suppose.
make sure the air box is down over the carbs, the box sometimes pops up if the clamps are over tightened all the rest of the ducts must be air tight, the restriction of all the air ducts and filter kinda choke the intake some what, the choke on the 650 isn't actually a butterfly that chokes off the air, it only opens an orifice to let extra fuel in, just removing the air filter on mine made the engine run very poorly, it was too free flowing to allow the available fuel to be sucked into the engine, try closing off the inlet behind the air filter housing with a rag and see what happens, the only thing that failed on my 2000 650 classic was the pick up coil which seems to eventually fail on most 650s from what i'v heard, the slides on my carbs got a little sticky so i polished the bores and slides with #0000 steel wool, now there nice and snappy not sluggish like they were
 

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Discussion Starter #5
80lbs front, 90lbs rear.... and severe carbon fouling... Back to the manual.... valve clearance tests next... then timing... wish me luck.
 

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Discussion Starter #6
Thanks Pauli. Most carb boots/intake covers are... tichy to say the least. I've had a ton of practice. Both these machines are over 16000 miles... so going through the maintenance list... after triple checking the boots, and covering the intake with a rag, no change. Draining the tank and cooling it off again. The low compression matches up on both bikes, oddly enough. Somethings outta whack here... I shall continue testing, and keep y'all informed. :)
 

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You are holding the throttle open when checking compression?
 

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Discussion Starter #8
Good morning Folks. My thanks to SLick Mick for mentioning what my tired, frazzled brain missed. Glad I checked this board this morning. With throttle wide open= 171 front, 171 rear. That's a relief. I wasn't prepared for tearing this down this morning... whew!
 

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Discussion Starter #9
So, after multiple checks of float level, grabbed a friend and started going through all the different basic test procedures... check for spark... good on front, almost none on the back... switched the plugs, both plugs work correctly... pulling the tank so as to test the coils... looking like this might be a pickup issue... what a nightmare... tracing back the issues.... wish me luck.
 

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From your description that the bikes run ok on the kickstand but sputter out when stood upright, these bikes have a fuel pump because the carbs are so high compared to the fuel tank.

if the fuel pumps are not working correctly (or are missing?) the carbs would have higher fuel pressure with the bike leaned to the left on the kickstand.

or maybe the fuel lines or gas shutoff valve is not right in the tank? leaning the bike left or right should not affect the spark unless there is a loose wire floating around somewhere.
 

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Discussion Starter #11
KCW, that was pretty much my thought process to begin with... I've been tracing the electrical all morning, found that the rectifier wasn't plugged in all the way.... however, correcting this did NOT solve the problem either. Followed the diagnostic diagram in the manual... and everything checks out other than the ignitor unit... Really not sure how to test the fuel pump for consistent pressure... It does turn on, and seems to be running at first... Is there a way to test that? I'd hate to just "throw parts at it". Gets expensive in a hurry. LOL. Thanks again for the help.
 

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I dont know the procedure for checking a 650's fuel pump, but Im sure there is one. Try googling it, might be on this forum or somewhere else.

Its an odd use for a fuel pump, not high pressure like a fuel injected engine, but it does pressurize the float bowl higher than what gravity from the tank would create.

If the pump is not working and fuel is just leaking through it, the bike will run like crap. Im sure there must be a pressure rating that could be measured with a pressure gauge, and flow rating that would flag a bad pump. Sorry I dont know the specifics.
 

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Discussion Starter #13
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So, it turns out that AFTER the ignitor burned out, the dude let this beasty sit for a long while, and then tried to figure it out on his own, but didn't know enough. After 3 days of cleaning fuel system, diagnostic testing, posting on this forum, and following wires... It runs perfectly with a new ignitor unit. My greatest and many thanks to those of you who helped me out, and hopefully this will help others who have similar issues. !!!!!!! :grin:
 

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You posted there were two VS650s acting the same way.

I take it you got one running right? Is the other the same issue?
 

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So, after multiple checks of float level, grabbed a friend and started going through all the different basic test procedures... check for spark... good on front, almost none on the back... switched the plugs, both plugs work correctly... pulling the tank so as to test the coils... looking like this might be a pickup issue... what a nightmare... tracing back the issues.... wish me luck.
how good is flow rate coming through the filter with the pump running, could be something as simple as a clogged pickup tube screen or a clogged fuel filter, i'd double check the bowl levels something is off there for the engine to run differently when leaned, when my pickup coil failed it started acting up only when hot in the end i could only ride a few miles before stopping to let it cool down then go a few more miles, that how i got it back home without towing it. luckily i was close to home so it wasn't to bad
 
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