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Only runs on left cylinder 0-1/4 throttle


J-Madd

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On the 2006 Banshee in my sig, carbs are sync'd, both sides getting fuel, both sides running in neutral but when the motor is under a load, the right side only fires intermittently up to 1/4 throttle, then it kicks in and and screams. I swapped plug wires, no change. I've tried 52 pilots and 48 pilots, no change. I half ass cleaned out the carb through the opening on the bottom of the bowl. (I couldn't get the bowl off at that time.) No change. I've now got the carb clean as can be.

 

I'm not sure what the float height should be. When I turn the carb upside down, the float rests all the way down in the carb, regardless of how it is bent. Is that normal? Is the float valve supposed to hold the float up? Gravity just pushes the float valve all the way in. Now I've messed with the bend and don't want to put it back together until I get some opinions.

 

Thanks

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Don't half ass clean 'em. Remove the pilots, and use a strand or two of speaker wire to clean out all the passages...and the pilot itself. Make sure the airscrew is removed and passage cleaned as well.

 

I set the floats level when turned upside down. Remove your needle. there is a spring-tip on it that hits the tab on the floats. make sure it is still "Springy"...

 

I don't know the exact height the floats should be, but...unless they're leaking, they're probably fine.

 

If they were stuck or not getting you fuel, it wouldn't be screaming after 1/4 throttle, quite the opposite would happen.

 

Dumb question, J-Madd...but are the plugs new and both gapped identical?

 

I'd almost bet it's a little dirt or sumthin in the carb on the pilot circuit.

To check easily, switch 'em....that wasy you'll know if it's carb or something else...

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Don't half ass clean 'em. Remove the pilots, and use a strand or two of speaker wire to clean out all the passages...and the pilot itself. Make sure the airscrew is removed and passage cleaned as well.

 

I set the floats level when turned upside down. Remove your needle. there is a spring-tip on it that hits the tab on the floats. make sure it is still "Springy"...

 

I don't know the exact height the floats should be, but...unless they're leaking, they're probably fine.

 

If they were stuck or not getting you fuel, it wouldn't be screaming after 1/4 throttle, quite the opposite would happen.

 

Dumb question, J-Madd...but are the plugs new and both gapped identical?

 

I'd almost bet it's a little dirt or sumthin in the carb on the pilot circuit.

To check easily, switch 'em....that wasy you'll know if it's carb or something else...

 

 

I only half ass cleaned them at first b/c a screw was stripped :baseball_bat: . I now have taken the carb off and removed all jets, air screw and choke and thoroughly cleaned. Both plugs are new and gapped at 0.18 (too narrow, I know now from reading other posts.)

 

 

So on the floats...........I can just set them so they only shut the gas off before it overflows? That's kinda what I thought. The float valve is still springy, but not enough to hold the float up w/the carb upside down. Switching the carbs is my next step if this doesn't work.

 

Thanks :beer:

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this is what i did 2 mine and i found out i had a rat nest in my pipe LOLOLOl

 

 

 

switch the carbs from left 2 right and see if the side that isint fireing switches???

 

 

worked for me

 

 

hope this helps :ninja:

 

 

glenn

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  • 5 weeks later...

OK here's what I've tried and the problem always STAYS ON THE RIGHT CYL.

 

- swapped carbs and plug wires left to right

- gapped plugs at 0.020

- checked reeds on right cyl.

 

Other than this problem, it runs great, Smoked a DS650 w/alleged 70 dynoed hp. I'm guessing I'd have at least 10 more hp on that dyno.

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I had a head gasket let go once which caused similar symptoms. Just a thought...

 

 

I was thinking head o-rings or base gasket myself. Last time I checked the radiator it was a little low, but I don't have a reservoir so it could have spewed out a little. However, no steam or water vapor appears to exit the silencer, no water beaded on the spark plug..........I've seen that before.

 

I forgot to mention that I checked compression. About 160 psi in each cylinder.

Edited by J-Madd
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I'm at a total loss on this. I checked the radiator and it's completely full. I've ran a tank of gas through it since I filled the rad up. It can't be the gaskets. What should I even look for next? A crank seal leak on the right side would burn crankcase oil, so that's not it. Is it possible that the porting is not identical b/t the 2 cylinders, thus one requiring more or less fuel at 0-1/4 throttle? I may put some bigger pilots in there and see what happens, even though I know the carbs and jetting is not the exact problem, but may hide it with larger pilots. Again..this thing rips from 1/4 throttle on.

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This is going to sound dumb...and maybe it's up in this thread elsewhere...

swap pilots, carb to carb. See if that helps.

 

Also, I get a strand or two of speaker wire to really clean out the small passages as found in the pilots....I'd try that as well.

 

Just off the TOTAL cuff.... What is your spark plug type, heat range and gap set to?

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This is going to sound dumb...and maybe it's up in this thread elsewhere...

swap pilots, carb to carb. See if that helps.

 

Also, I get a strand or two of speaker wire to really clean out the small passages as found in the pilots....I'd try that as well.

 

Just off the TOTAL cuff.... What is your spark plug type, heat range and gap set to?

 

 

I have actually swapped entire CARBS left to right, but at this point I'll try anything. Plugs are NGK br8eix (iridium) gapped at approximately 0.020. They were at 0.018 and I gapped them the next size feeler gauge..I could only find my metric gauges and didn't calculate the inch to mm conversion. I think it might have been 0.5 mm, not sure.

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  • 3 weeks later...

UPDATE:

 

I changed the 48 pilots to 52s (couldn't find my 50s). It idles now, but that didn't fix the problem. However, by the end of the day Sunday both cylinders seemed to be acting normal, but my hydraulic clutch lost all pressure...............don't know what's up with that yet. At first I could pump it up and get it to work, then it finally quit all together.

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Don't overlook an Intake Air Leak on the Right Side.

 

With excess air getting in, you could get those symptoms.

Once you are pouring the extra fuel to it 1/4 and up, it runs (albeit probably lean).

 

But, you would have too much air to run at idle? possibly.

 

I'd check for Air Leaks on right Side, it can't hurt, include the head gasket on that side too.

 

I swore that I didn't have an Air Leak, and the leakdown test proved me wrong.

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Don't overlook an Intake Air Leak on the Right Side.

 

With excess air getting in, you could get those symptoms.

Once you are pouring the extra fuel to it 1/4 and up, it runs (albeit probably lean).

 

But, you would have too much air to run at idle? possibly.

 

I'd check for Air Leaks on right Side, it can't hurt, include the head gasket on that side too.

 

I swore that I didn't have an Air Leak, and the leakdown test proved me wrong.

 

 

I forgot to mention that it smokes more out of the RIGHT when I give it gas in neutral. When it warms up, I can't tell b/c it barely smokes at all. If I had an air leak, I'd think it would smoke less, but I'm not ruling that out. Could it be an air leak on the LEFT SIDE and my pilots are too rich for the right side, but the LEFT is compensating with the air leak?? Just a crazy thought.

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