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Left cylinder doesn't fire below 3/8 throttle


TWILES

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I bought an 01 thats stock with Pro Circuit pipes, K&N filter, and 40 pilot jets. When you get on up close to half throttle it hooks up and screams on both cylinders and when sitting, if I'll push the throttle far enough that it fires and keep revving it out that far, it continues to fire. At idle, its dead but it idles. I pulled the plug and its sparking really good which is weird. My conclusion is that the pilots jets are too big and that cylinder is not in the best shape and its flooding that cylinder out. Once the slide is opened and its getting enough air, it fires the gas like its should. I've ordered 27.5 pilots but they won't be here till next week and this is bugging me. Anyone have any other ideas. The wiring was stripped down to bare minimum and looks like shit but if it was a sensor issue I didn't think it would get above idle on either cylinder.

 

Travis

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I have never seen a Banshee with stock carbs and near stock displacement that needed a pilot jet bigger than 30. Since it won't fire until it comes on the main jet, I think the pilot is too big. The other thing to look at is the plug wire and boot on the left side. If there were problems with the stator, CDI or coil, it should affect both cylinders, not just one. I suppose if the pickup coil gap was drastically different between the 2 nubs on the flywheel, it could affect 1 cylinder and not the other, so you may want to check the pickup coil gap on both nubs of the flywheel.

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Clean carbs comepletely, don't just give them a quick douche and call them clean. Have to take everything apart. Set float level. Syncronize carbs. Adjust air screw. Clean carbs one at a time as parts are different. Don't forget to replace choke crossover tube. Also check pick-up gap at both nubs. :cheers:

 

The carbs are spotless and synced and everything is there, inside and out. Again, it idles great but only on the right cylinder. The plug on the left fires when I kick it but something is keeping it from igniting the fuel when its running up till the slide is opened close to half. I really didn't catch it until I grabbed the left pipe and it was cold. Run it up to half and rev it past half a few times without letting it drop back to idle and the pipe gets just as hot as the right. Let it drop back to idle and the pipe cools off.

 

The pick up gap hasn't been checked. I'll check those when I get the 27.5 pilots in this week along with the reeds. What is the clearance supposed to be?

 

Travis Wiles

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Carbs and idle are not Sync'd correctly. Did you Sync with a vacuum tool or eye? Use a tool after you get the correct pilots and you will be fine I think

 

I had a minute today to mess with it and I swapped the plug wires and it started running on both cylinders.

 

How much Syncing can you do to these carbs? The slides open exactly the same, the jets are the same, the needles are the same and the idles are turned out the same.

 

I'll dig deeper Friday. I'll have the jets tomorrow.

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I had a minute today to mess with it and I swapped the plug wires and it started running on both cylinders.

 

How much Syncing can you do to these carbs? The slides open exactly the same, the jets are the same, the needles are the same and the idles are turned out the same.

 

I'll dig deeper Friday. I'll have the jets tomorrow.

 

These guys suggested that sync tool becase, your eye might say the slides look good but the vacuum measured by the tool could show show differnt readings through each carb. The sync tool is where its at to be sure and answer your question, "How much Syncing can you do to these carbs?"

Edited by cline
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