1998 banshee tuning problem

[geoffroy]

Hello everyone

i'm new to the forum and i'm from quebec canada.

 

i bought a banshee that had a blown motor(it gripped on the generator side)the cylinders where fine they had already been peirced once before. 64.25 mm. I ordered 2 wsm pistons and top gasket kit and i started putting everything back together. i put a new rebuilt crank and crank seals. and torqued everything

it has a cool head made by pro design with #2 domes i beleive.

I took the compression once finished and it gave me 135 psi on both cylinders.

 

reed vavles look good ( it has vforces) and the rubber couppling is nice aswell.

 

I noticed that the carb on the side that it gripped the air screw was almost completely unscrewed. I put everthing back to stock specifications. 1.5 turns out on the air screws (its between -10 and -30 degrees celcius up here in quebec). I put the needles on the 4th notch. I have 260 main jets and 27.5 pilot jets.

 

i got the bike started. its starts great, i ajust the idle at about 1000 rpm. I go for a ride and the bike is running strong and seems not to pink or anything.

i bring it back in the garage and i take the exhaust temperature with my laser gun. the left side exhaust is alot hotter than the right side exhaust (about 3 inches away from the cylinder)...the left exhaust was at nearly 200 and the right one was at about 100 degrees celcius. I then completely took the carbs apart and cleaned everything. i put everything back up and even on idle, the left side carb is about 20-25 celcius hotter than the right side.

 

did this ever happen to you guys? what could be the problem?

 

as for engine mods i've got a k&n air filter, fmf pipes and silencers, vforce reeds and the cool head.

 

if you guys think that it is the vforces...it is possible to interchange the two reeds to see if the problem switches side? the plugs are new and i tried swithing the plug wiring...still no effect

 

jeff

Edited February 19, 2006 by geoffroy

[Banshee~]

What have you done to the airbox (ex. take lid off, take snorkel off)? Your jetting might be lean, but I dont know why they would be different temps. You could have an airleak somewhere, but thats just a guess.

Edited February 20, 2006 by Banshee~

[geoffroy]

i have done no mod with the airbox...exept for the snorkle that i have taken off.

also forgot to mention that the elevation here is 200 feet.

 

if it was an air leak, wouldn't it tend to rev higher?

 

i thought it might have been because of the choke, but i took the choke of a freinds banshee and it still does the same thing

 

i see you guys out there running with 300 + main jets with about the same equipment as i have. what i dont understand is that i went to yamaha and they told me 250-260 for the mains and stock pilot.

 

jeff

[thegroup]

i have done no mod with the airbox...exept for the snorkle that i have taken off.

also forgot to mention that the elevation here is 200 feet.

 

if it was an air leak, wouldn't it tend to rev higher?

 

i thought it might have been because of the choke, but i took the choke of a freinds banshee and it still does the same thing

 

i see you guys out there running with 300 + main jets with about the same equipment as i have. what i dont understand is that i went to yamaha and they told me 250-260 for the mains and stock pilot.

 

jeff

476084[/snapback]

and half the time yamaha doesnt know WTF they r talking about. ur running lean on the hotter side. just try dif. jet sizes and see what u get. i know a little bit about jetting, but not enough to say "this is what u need"

[geoffroy]

ok, i'll try other jets

 

but what i dont understand is that they exhausts are not at the same temp...

 

what size should i start off at?

 

i will try inverting the two carbs and the reeds to see if the problem is really in the carb.

 

jeff

[geoffroy]

with the equipment that i have would a 300 main jet be a good starting point?

[greg_banshee]

hey man

i live in Nova Scotia i know we don't get AS Cold as you guys do in Quebec but we do get cold (-24 here the other day & needless to say i wasn't riding the Banshee)and i run a 280 main & a 40 pilot and it seems to run Perfect around normal summer temps & when it gets colder i run a 300 main, i don't run er as much when its cold but around 0 degrees to -2 is nice, after that ... to cold for me haha and the 300 keeps it just right! There is only about a 3 degree celcius difference between each cyl & exhaust. your elevation will be different then me cause i'm at or near sea level. i'd try a 310-320 or even tad bit bigger ... just to be on the safe side, i'd rather be rich then lean

 

& Oh Ya lol i think we better give the Canadian Mens Hockey team over there ... A FUCKIN HEAD SHAKE because they need something to wake up all that POWER ! lol Go Canada Go !

[geoffroy]

thanks greg!

 

i'll go and buy those tomorrow and i'll check my exhausts temp more closely.

 

i think it might be because my engine is freshly rebuilt, maybe the piston on the left side is a tad bit tighter than the left one....

 

 

jeff

[thegroup]

thanks greg!

 

i'll go and buy those tomorrow and i'll check my exhausts temp more closely.

 

i think it might be because my engine is freshly rebuilt, maybe the piston on the left side is a tad bit tighter than the left one....jeff

476607[/snapback]

re-read what u typed

[geoffroy]

i'm sure everybody understands anyway!

 

jeff

[sheenut05mx]

How do the plugs look? Have you done a plug chop?

 

Most likily what is causing the temp, to differ from pipe to pipe is one cyclinder is a littler richer or leaner than the other, causing temps to vary on that pipe. Change Idle air screws independenly of one another the seting will varity. I would also raise you main jet a few sizes depending on how the plugs look.