I want a Banshee!!!!

[mennis1971]

I can honestly say my shee never overheated in the woods, and it saw a lot of them. Now sometimes at the dunes in the heat of the summer it would puke a little coolant, but it NEVER overheated. I rode the crap out of it. BTW for water skipping, a shee works great!

[Bowtie316]

well guys add me to the list. today picked up my first ever atv and its a banshee no less hahahah. been on single cylinder dirtbikes since '83 and i just wanted something different. 4 wheels and 2 pistons seemed to fit the bill perfect. anyways its a '03. from what i can tell its all original. guy i got it from said he never did nothing to it and was pretty sure the original owner he got it from never did nothing to it. looks like the jugs and head never even been off. only bolts on the whole bike that appear to even have a wrench on em were the lug nuts and the plastic cover over the front sprocket maybe to replace the chain since the masterlink is on backwards or perhaps they just flipped the chain to try and get double the life, hell im not sure. got some douglas wheels with goofy looking v shaped paddles and a factory yamaha service manual with it also. manual will be handy since i dont know a damn thing about these machines

now before you go busting my balls for buying a stocker let me explain. a built up bike has quit a bit higher initial cost. 5K-8K range for the ones i seen recently. ya it probly cost 2x that much to build them originally so you'd be getting a hell of a deal but i just didnt want to fork out that much cash. besides i like to build my own stuff. in the end i may end up with a 8k bike but if its a few parts here and there over a period of time it wont kill my wallet so bad. a prebuilt bike by someone else gives me no satisfaction. plus i want to mess around with these yamaha cylinders alittle bit and see how fast they can go. ported aftermarket cylinders leaves me nothing to tinker with. anyways im pretty stoked to have something new to mess with. darn shame its not a honda or ktm but it'll do  . one question, is the stock pistons prone to cracking ?  dude said he didnt think there was even 50hrs on it but i thought of having a look through the intakes and exh to be sure nothing looks like its gonna explode

Looks like a nice find, I thought I was going to come out ahead finding one that already had some of the mods I wanted, but it turned out costly.

I was surprised to read that this is your first ATV, you mean you don't even have a trx250r?

[Bowtie316]

did you get it running yet ?  how much vibration is normal on these things ?

Yeah, It was only down for a week.  It is weird, it vibes just above idle to about 4000 rpm (guessing) then is silky smooth the rest of the way up. My buddies bashees are similar.

Oh and it feels like a couch compared to my 250r as well, like the whole couch, especially riding a wheelie.

[udontknowme]

this one is smooth idling. then if you push the throttle to about 3-4k it buzzes then above that it smoothes right out. i figured it was normal. otherwise im sure it would vibrate all the time if the rods or something was on its way out. single cylinders usually have a spot in the rpm where it buzzes like that also. i thought there was some strange engine noise but it appears to be just the chain going over that white slider thing at the front of the swingarm because it sounds fine when your not moving.  im happy with it and its fun to ride. even stock these things are pretty fast. but ya its like a couch compared to my '13 ktm :biggrin-new:

[udontknowme]

installed the first piece of bling today :excitement:. matoon nuetral switch cover. the stock plastic one was cracked. not even sure what the hek the cover is for but i didnt see any point in using another plastic one. im really liking this machine even though i havent rode it much yet. mostly just been cleaning everything up and inspecting stuff. went through all the linkage to be sure it in good shape and greased. pulled out the reed blocks and checked pistons for cracks etc. cooling system must of had the original stuff so i got that all cleaned out. probly get a timing plate, clutch and flywheel covers next. straight cuts, 8 plate basket and lockup probly be after that. leaning toward a lonestar chassis also but that might be more around spring time

[Bowtie316]

. probly get a timing plate, clutch and flywheel covers next. straight cuts, 8 plate basket and lockup probly be after that. leaning toward a lonestar chassis also but that might be more around spring time

Wow, you're not even going to mess around huh?

My first mod will be a roundhouse swinger I reckon.

[udontknowme]

anyone happen to have a banshee owners manual ?  got 2 different service manuals and ill be damned if there aint a jetting chart in either one. wondering if the owners manual has a chart that lists approximate jet sizes for altitude and temp.  this engines alittle boggy at low speed. im thinking its lean but im not sure because its acting different than my other bikes. was gonna get a size bigger pilot and see what happens but a chart would be helpful. ya and i dont know the first thing about mikuni so that aint helping matters

[Jerry Hall]

anyone happen to have a banshee owners manual ?  got 2 different service manuals and ill be damned if there aint a jetting chart in either one. wondering if the owners manual has a chart that lists approximate jet sizes for altitude and temp.  this engines alittle boggy at low speed. im thinking its lean but im not sure because its acting different than my other bikes. was gonna get a size bigger pilot and see what happens but a chart would be helpful. ya and i dont know the first thing about mikuni so that aint helping matters

Tune a Mikuni just like would any other brand of carburetor.  A lean or rich symptom with a Mikuni is the same as a Keihin.  Mikuni jets are sized in flow rates and are not a diameter like Keihin carbs.  Keihin jets are coded hole diameters.  A 170 Keihin jet is 1.70mm. A 175 is 1.75mm and so on.  You do not have to calculate the flow area with Mikuni jets if you want to make a certain percent change in fuel flow.

Example;

If you are running a 400 Mikuni main jet and want to richen it 10 %, just install a 440 main jet.  If you are running a 170 Keihin main jet and want to richen it 10 %, calculate the area of a 1.70mm hole, multiply it by 1.10 and then calculate what diameter hole would have this area.  This is not something that most guys can do in  their head.  Increasing the 170 Keihin main jet size 10 %would require a 1.783mm diameter jet.

If you are tuning without any instrumentation, you can estimate the jetting changes needed by using the following approximations.  A 1000 ft change in elevation will require about a 3 % change in fuel flow at wide open throttle or a 3 % change in main jet size.  A 15 F. degree change in the intake temperature will require about a 3 % change in main jet fuel flow.  Most manufactures make each increment in their carburetor tuning parts approximately a 2 % to 3 % change.

Example:

Going from a 400 to a 410 Mikuni jet is a 2.4 % change.  Going from a 170 to a 172 is a 2.3 % change.  

Moving the needle one clip position, changes the fuel flow in the 3/8 to 3/4 throttle position about 3 %.

Moving the pilot jet one increment in size, changes the fuel flow at closed throttle about 6% to 10 % and then can be fine tuned with the air screw to get a smaller incremental change in idle fuel flow.  



Remember a 3% change in air density will require approximately a 3% change in main jet size but the fuel flow at an idle or partial throttle will not change very much.

[udontknowme]

no place in town had the jets for this carb. had to order some but theyll be here thursday. hopefully this will fix the problem and i wont have to mess with changing the needle. it bogs pretty bad when you crack the throttle from a idle so maybe it could be the low speed section of the needle also. seemed to decrease quit a bit with the air screw turned in almost all the way so maybe the richer pilots will fix it

hey jerry i got a clymers and oem service manual and one says to use a resistor plug and the other says nonresistor. isnt it common practice that you dont want two resistors in the same line ?  so if the cap has a resistor then you would use a nonresistor plug ? normally the caps ive seen will either say nothing meening they are nonresistor or theyle say what the resistance is but theres nothing on these caps but they almost look like a resistor cap to me because theres a donut shaped thing right near the end of the wire, pretty sure theyre original oem caps and wires. in the last few days ive tried both types of plugs and not sure i can tell much difference but i was wondering if i should be using one or the other or if it would hurt the ign system with wrong plug ?

[udontknowme]

well i got this thing figured out. tried the next bigger pilot which was still just a tad small but with the air screw 1/2 turn out it sounds 100 times better than it did. had a massive bog but its all but gone now. try one more size bigger tomorow which should be perfect and allow the air screw to be 2 turns out

[JohnTabata1]

Dunes only fo me. I like both TRX250R n Banshee. Nothing faster fo sand drags than a Banshee tho.

[DnB_Racing]

no place in town had the jets for this carb. had to order some but theyll be here thursday. hopefully this will fix the problem and i wont have to mess with changing the needle. it bogs pretty bad when you crack the throttle from a idle so maybe it could be the low speed section of the needle also. seemed to decrease quit a bit with the air screw turned in almost all the way so maybe the richer pilots will fix it

hey jerry i got a clymers and oem service manual and one says to use a resistor plug and the other says nonresistor. isnt it common practice that you dont want two resistors in the same line ?  so if the cap has a resistor then you would use a nonresistor plug ? normally the caps ive seen will either say nothing meening they are nonresistor or theyle say what the resistance is but theres nothing on these caps but they almost look like a resistor cap to me because theres a donut shaped thing right near the end of the wire, pretty sure theyre original oem caps and wires. in the last few days ive tried both types of plugs and not sure i can tell much difference but i was wondering if i should be using one or the other or if it would hurt the ign system with wrong plug ?

on the banshee you don't need resistor plugs, as there are no sensitive solid state devices for the RF or RFI to interfere with ...but with that said you wont hurt anything running resistive plugs, they do use a small bit more voltage then non, meaning a slight small gap

[udontknowme]

good to know. electrical stuff aint my area of expertise. theres a donut thing at the end of the wire near the plug boot which i thought might of been a resistor but maybe its something else. ill just stay with non resistor plugs

[Jerry Hall]

no place in town had the jets for this carb. had to order some but theyll be here thursday. hopefully this will fix the problem and i wont have to mess with changing the needle. it bogs pretty bad when you crack the throttle from a idle so maybe it could be the low speed section of the needle also. seemed to decrease quit a bit with the air screw turned in almost all the way so maybe the richer pilots will fix it

hey jerry i got a clymers and oem service manual and one says to use a resistor plug and the other says nonresistor. isnt it common practice that you dont want two resistors in the same line ?  so if the cap has a resistor then you would use a nonresistor plug ? normally the caps ive seen will either say nothing meening they are nonresistor or theyle say what the resistance is but theres nothing on these caps but they almost look like a resistor cap to me because theres a donut shaped thing right near the end of the wire, pretty sure theyre original oem caps and wires. in the last few days ive tried both types of plugs and not sure i can tell much difference but i was wondering if i should be using one or the other or if it would hurt the ign system with wrong plug ?

I use the following jets as a baseline in our modified stock carbs using the following engine build.  Yamaha Banshee cylinders with our porting, our modified stock head, V3 or V4 reeds, stock cross-over tube, Toomey T-5 pipes and silencers, Stock air box, lid removed, Pro-flow flange with K&n filter, timing advanced 4 to 5 degrees,  330 to 350 main jets, 25 to 30 pilot jets, stock needles in the middle clip, stock slides, air screw 1 1/2 turns, B8ES or BR8ES spark plugs gaped at .018" to .020".  The above set up will make over 70 -75 Sae RWH on our dyno.  This combination is used for serious duners and is very reliable.  

The stock spark plug caps are 5K ohm resistor caps.  About half of the ones I check are open and need replacing.  I replace them with a NGK cap part number TB05EMA.  These caps are also a 5K ohm cap.

Like DnB racing said, you do not need resistor plugs or caps but it eliminates a lot of electrical noise given off by the ignition.  Resistors caps and or plugs make it nice if you ever take it to the dyno or run a data  acquisition system.  The Dynojet dynos will not tolerate very much electrical noise.  The electrical noise makes the dyno tach intermittant and sometimes it freezes up the dyno electronics.

[Bowtie316]

I use the following jets as a baseline in our modified stock carbs using the following engine build.  Yamaha Banshee cylinders with our porting, our modified stock head, V3 or V4 reeds, stock cross-over tube, Toomey T-5 pipes and silencers, Stock air box, lid removed, Pro-flow flange with K&n filter, timing advanced 4 to 5 degrees,  330 to 350 main jets, 25 to 30 pilot jets, stock needles in the middle clip, stock slides, air screw 1 1/2 turns, B8ES or BR8ES spark plugs gaped at .018" to .020".  The above set up will make over 70 -75 Sae RWH on our dyno.  This combination is used for serious duners and is very reliable.  

The stock spark plug caps are 5K ohm resistor caps.  About half of the ones I check are open and need replacing.  I replace them with a NGK cap part number TB05EMA.  These caps are also a 5K ohm cap.

Like DnB racing said, you do not need resistor plugs or caps but it eliminates a lot of electrical noise given off by the ignition.  Resistors caps and or plugs make it nice if you ever take it to the dyno or run a data  acquisition system.  The Dynojet dynos will not tolerate very much electrical noise.  The electrical noise makes the dyno tach intermittant and sometimes it freezes up the dyno electronics.

Wow Jerry, great info, Thanks!