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Discussion Starter · #1 ·
Hello all, I'm new to the site. I am running out of options on a fix. My daughter bought a 2000 650 vstar classic. It sat for 2+ years. The previous owner said it only ran on back cylinder when he parked it (didn't have time to mess with it). I installed a new battery, rebuilt carbs, cleaned entire fuel system, replaced plugs, wires and ignition coils, pickup coil and stator. Will test rect/reg today. Starts right up and idles good with the choke pulled, bogs down when trying to rev it up, and only running on rear cylinder. Bike has 22,000 miles on it and I have spark and fuel on both cylinders. Compression checks equal on both cylinders. I don't know how to test the CDI unit. Possibly front cylinder weak spark? Any advice would be greatly appreciated.
Thanks
 

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It is WAY more likely that you have a fuel delivery problem on the "dead" cylinder.
Does it run better with the choke ON more ?
Are you testing with stock air intake and filter and stock pipes on it ??

It may not be getting ENOUGH fuel to the bad cylinder.
Will it rev up better if you introduce some starting fluid or propane into the air input to the bad cylinder ?

I suggest a healthy dose of Berrymans B12 Chemtool in the gas and then run it a couple of times over a few days.
 

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WHS^ plus check for tank vent and the idle circuits probably are blocked. You may have a slow fuel supply....even a slight kink in the line will cut down fuel flow....My bandit 1200 had to have a slight downward alignment of the fuel hose or it would starve the fuel delivery
 

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Discussion Starter · #4 ·
Thank you for the response. Aftermarket V&H exhaust. Stock air intake & filter. It does run better when it's fully choked, but still, only the rear cylinder. I will try introducing starting fluid and see how it reacts, also I'll add the B12 And verify fuel lines are not kinked.
Thank you both for the advice !
 

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Sounds like the idle circuit in the offending cylinder is partially blocked....leave the fuel treatment in overnight or longer if possible.
 

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Discussion Starter · #6 ·
Thank you both VERY MUCH for the advice. The Berryman B12 worked! I added it to the tank and started it, first 10 minute run didn’t have an effect. I let it sit overnight, started it and within a couple minutes it started backfiring and firing on the front cylinder. It is now running great! Truly appreciate the advice…….Thank you.
 
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