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Banshee bogs bad but idles great!


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Hey Everyone!

 

First off, GREAT forum with TONS of info on everything and great people. Im new to the banshee world and am having a problem with my 99' shee.

 

I bought the bike in a box basically b/c the previous owner locked up one cylinder and let it sit for a year. I put new cylinders, pistons, gaskets and rings on the bike and have 130~ psi of pressure on each cylinder. Sparks seems good but not too experienced in electrical so not sure if its 100%. I did take the stator cover off and set the pickup coil gap with a feeler gauge and cleaned the terminals. The bike will idle perfect with a bit of fuel leaking out each pipe but when i go to take off, i have to really clean out the pipes to get it to rev nice and even then it seems a bit off. 

 

I have synced the carbs with the windows and i DO have the tors tops but the tors system is disabled (unplugged the "brain"). I've got new fuel line and cleaned the carbs out. All the jets are stock for my year (200 main and 25 pilot) and my needle clips are at the stock position (middle posistion). Now the only thing he has done to the bike is added a k&N high flow air filter, boost bottle and v-force 3 reids. Im also unsure if i am missing any parts to the bike ( seems like there should be o-rings for the headers? and also maybe a spring missing between the headers?)

 

I've tried pretty much everything i could think of now [both carbs are set up to STOCK specs as per my manual (air screws are 1 1/2 turns out, needle position, jets)] and it STILL has to much fuel going into the engine. Like i said before though if i get it cleaned out a bit it will run semi ok. Not a ton of smoke comming out of the pipes but just enough (unless im just taking off then its a smokeshow). I can upload a video or send it if needed.

 

Any Help would be much appreciated! 

 

Thanks!!

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Welcome!!

 

What is your elevation?

What oil are you mixing and at what ratio?

 

I'll tell you right now, the K&N and VF3's are going to require more fuel because they are much higher flowing than the stock components.

Get that boost bottle out of there, it's a gimmick.

I have a stock cross-over tube I'll sell you for $10 paypal gift and I'll cover shipping.

I have the stock intake too incase yours is cracked around the boost bottle interface, a well known area for intake leaks.

Let me know!

 

Turn your air screws in all the way lightly seated and see how it runs then.

Many people, think when an engine boggs, it's because there's too much fuel.

 

By turning in your air screws you are effectively adding more fuel to the intake.

Try it, you'll see the difference, if not, then build yourself one of these and hunt down a possible air leak.

http://bansheehq.com/forums/index.php?/topic/110585-leakdown-tester/

 

Your throttle should snap quick off idle.

It should Brrraaappp.

Not Brrrooooaaaagggg.

Think about it, your intake tract is waaayyy freer flowing than stock.

Why in the world would stock jets be supplying too much fuel??

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Is this a single K&N in your airbox?

Oh, and make sure that K&N filter is not over oiled or it will choke the air intake.

Test this by running your motor without the filter.

But make damn sure the airbox, if you have one, is spotless.

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Thanks for the quick reply Strm Trpr!

 

My elevation is 630 ft above sea level and i mix at 20:1 (thats what the book says to mix at). and ill try the air screw trick tonight and the air filter off. Just cleaned the filter so not sure if thats it but i dont have anything to plug off the boost bottle holes on my intake. Im also up in canada so i dont know if you want to cover shipping! also where does the crossover tube go (im guessing where the bottle is now)? haha i checked for intake leaks with carb cleaner (i know not the best way) and it didnt rev up at all so i dont think i have any leaks. Also i checked everything over good before installing it beause i had it ripped down to almost nothing and cleaned it all.

 

Ill post results tonight!

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Thanks for the quick reply Strm Trpr!

 

My elevation is 630 ft above sea level and i mix at 20:1 (thats what the book says to mix at). and ill try the air screw trick tonight and the air filter off. Just cleaned the filter so not sure if thats it but i dont have anything to plug off the boost bottle holes on my intake. Im also up in canada so i dont know if you want to cover shipping! also where does the crossover tube go (im guessing where the bottle is now)? haha i checked for intake leaks with carb cleaner (i know not the best way) and it didnt rev up at all so i dont think i have any leaks. Also i checked everything over good before installing it beause i had it ripped down to almost nothing and cleaned it all.

 

Ill post results tonight!

 

20:1 is part of your probelm.

You have a seriously rich oil/fuel mix.

Way too much oil in there and not enough fuel parts per million.

Think about it.

 

What oil are you running?

I run Yamalube 2R.

I have forever and I run it at 40:1 with no problems at all, ever.

That's one 16oz bottle or pint to 5 gallons of 91 octane.

I had a stock 87 motor that I had bored to .020" over and ran the balls out of that motor since 95 on 40:1 2R for probably a good 60 hours and it still ran when I pulled it and sold it.

 

Drain your fuel tank, and your carbs.

Make sure and blow out the pilot jet and main jet real good with carb cleaner and an air compressor

Mix a fresh batch of fuel at 32:1 if you're so paranoid.

 

Amsoil Dominator, I believe is what it's called, is engineered to run at 50:1.

 

The service manuals for the Yamaha 2 stroke 350cc motor was written in the early 70's when it started life as an air-cooled RD350 street bike w/oil injection.

 

Oil has come a long way since then, my man....

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I run Lucas semi synthetic oil.

 

So I came home tonight and remixed my oil 32:1 and it ran a bit better. Than I noticed that the right carb was spilling fuel out of the overflow so I fixed that (float was out of adjustment). I threw some new plugs on and checked spark and both are crisp and bright blue. It ran great for a min but still seemed to be not quite as quick of a response as some videos I watch. But when I took the air filter off to see if that changed anything I noticed the left side seems to be misfiring fairly often so I felt the pipes and the left side is defiantly running cooler than the right and smoking a whole lot more when revved... no air leaks with the carb clean test and running the air screws in doesn't seem to help.

 

I let it run 10 mins with the new plugs in it and the left side had a little bit of fuel on the plug but the right side had more... the left pipe was also throwing black fluid out of the silencer onto the ground so I'm stumped.....

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With the air filter off and the engine off, can you see the carb slides move up and down?

If so, they must lift off their seat exactly the same time.

I'm not sure how to adjust that with TORS.

Maybe it's the knob on the TORS boxes on top of the carbs?

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Ya I synced the carbs and me and three others agree they're moving at the same time... I don't have a vacuum gauge or carb sync or nothing but I had to tights and loosen the throttle cable to sync em.. the knobs on top of the tors are for idle adjustment they just move the slides and needle up and down... everything seems good there but I can recheck em tmo... got too frustrated tonight haha

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Cool, try switching spark plug wires and see if the right side misfires and runs cooler.

If it misfires on the right side now, then check the resistance of the spark plug wires.

You might have a bad wire, some rust or some crud on the connection where the wires connect to the coil.

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