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Discussion Starter #1
First of all this is my first v twin motorcycle. Picked it up for $400, it was complete but has been sitting a while. First thing i did once i got it home was clean out the carbs and fuel tank. The carbs didnt look bad, but did need a cleaning. After i put everything together, it starts fine, but only runs on 1 cylinder (the back cylinder). The front has spark, and gets gas (plugs are wet), but not sure what to look at next. I would really like to get this bike running good because me and a couple buddies want to make a small road trip before the end of summer. Any help is appreciated.
 

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Discussion Starter #2
Heres a video of it in as is condition, it was taken with my cell phone so it sounds a little weird, i think most of the noise is the carbs...

 

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Well like you said you have two of the three necessary components (spark, and fuel). The last one is air.

Is there anything restricting flow in the airbox, or exhaust pipe?

Have you checked the compression in that cylinder? It won't fire if the compression is too low.

Is there a good spark on both plugs?

Here's a good troubleshooting list.
4-Stroke Trouble Shooting
 

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Discussion Starter #4
Spark plugs are new, haven't tested compression as i don't have a tester, nothing seems to be restricting air flow either way, ill see if i can find a compression tester to borrow.
 

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Discussion Starter #5
Just for the hell of it, i went outside and started it up and put my hand in front of the carb for the front cylinder, and there is no suction.... what could cause this?
 

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Valves out of time or damaged.

Ultra-low compression.

Plugged exhaust pipe maybe.
 

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Discussion Starter #7
Okay learned some more ****, if i hold the throttle barely open, the front cylinder will have good suction and will fire. There is no throttle cables on it, so I'm guessing that's causing the butterflies to be to far shut, am i crazy or does that make sence?
 

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Just guessing here but sounds like the carbs are way out of sync. Have you downloaded the repair manual? If so check out section 2-10.
 

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^ x2 ^
 

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Discussion Starter #10
Can you supply me with a link to where i can download that repair manual?

If they were out of sync, would that make it fire on one cylinder at idle then run fine above idle?
 

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Discussion Starter #12
Okay so it says if i back off the 7mm nut, it decreases vacuum in the rear cylinder, does that increase vacuum on the front cylinder at the same time? Or is there another nut to adjust the front butterfly too?
 

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Discussion Starter #13
Turned that little 7mm screw like 8 turns out now and still no suction from the front cylinder at idle.....

Also tried to see if it would move under its own power and once i start letting out the clutch it just boggs, and if i give it gas once it starts bogging it just dies and wont move under its own power.....

I dont even know where to start to get this thing running good..
 

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Turned that little 7mm screw like 8 turns out now and still no suction from the front cylinder at idle.....

Also tried to see if it would move under its own power and once i start letting out the clutch it just boggs, and if i give it gas once it starts bogging it just dies and wont move under its own power.....

I dont even know where to start to get this thing running good..
If you have spark at the plugs, you have a fuel problem. If your plugs are wet, you have a possible float problem, main jet problem, or air/fuel mixture set too rich.. The float might be stuck open or there is a leak in the float and it is sinking and not closing the needle valve, or not adjusted right. The pilot jet sounds like it could be plugged, no idle speed but higher rpm speed. Not to be able to start or run under load is because you are not controlling the butterfly ( you stated the throttle is not connected .. A carb sync is a long way off, the bike has to be running and you need to be able to control your rpms to sync the carbs. A carb sync will help erractic running and low speed problems but it is more for tuning than for correcting a fuel problem. JMO
 

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Discussion Starter #15
Throttle cables are on, revs fast and good responce, front cylinder does not fire at idle nor has any suction at the carb. I cleaned the main jets and pilot jets...
 

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Throttle cables are on, revs fast and good responce, front cylinder does not fire at idle nor has any suction at the carb. I cleaned the main jets and pilot jets...
Sounds like part of your problem is solved. From apprx. 3000 rpms and up your engine is running on a combination of the main jet and pilot jet. From start to approx. 3000 rpm the fuel is supplied by the pilot jet only. The only way fuel can get to either the pilot or main jet is through the float and needle valve. I would check the float, check the pilot again, soak the inside of the carb with carb cleaner and then blow out every orifice with compressed air.
 
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