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Discussion Starter #1
allrighty on my bone stock 98 F3
D and D sho in Go alum. slip on
K and N factory replace filter

would i need to re jet or would i be fine?
thanks
 

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you dont need to. but you might anyways just to get alittle more
out of your ride.

im running a full D&D pipe, factory ignition advancer and a K&N
filter. i had to have mine jetted. stage 2.
it makes 87.7 hp at the wheel at 11,800 rpm
 

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Discussion Starter #3
thats pretty nice specs....i'll prob stay stock jets if i sont have to go bigger....my air filter is so dirty right now its almost all black...i bet when i throw the slip on and air filter i will noticed a differnce
 

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honestly your stocks are like 138 and 140
im running like 122s jets

so your actually running richer then i am.
when i did my motor swap i used 94 motor. which has smaller
carbs then a f3 motor. only 2mm difference. im running f3 carbs on the f2
motor.
 

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you dont really need to jet it. but it will be flat in response. if my scanner was
working i would post my dyno sheet.

my power curve is idle to 2400rpms then flat to 2800rpms then a straight all the way up to 11,800 no dips

the flat spot is because of the low speed and high speed valve being permanlety adjusted slightly opened for the low speed adn fully opened for the high speed one.

these valves is the thing that is on the back of yoru airbox with all hose on it.
 

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Discussion Starter #7
that would be the three hoses with a filter looking object connected between then or youre talking about the power valves in the venturi of the carbs?
 

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you got it. the hoses run up to the front of the bike. they look
like deer whistles. one is for the low speed and the other is
high speed they run off your speedo. but since i dont have the
electric speedo anymore since a f2 motor doesnt have the
sensor for the speedo. the shop that tuned my bike had to
bypass my valves so the would stay where they are.
 

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Discussion Starter #9
ohhh now the mystery is laid to rest....i know what they are for now....so if i put the full exhaust the flat spot would be really noticeable? or would i have one at all?
 

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youll have power but not like it would with it being tuned for the system. you can ride with the pipe on depending on how much the pipe is for performance. and might be happy with it but for optomize performance youll need to have it properly jetted.
 

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Discussion Starter #11
i completely understand....i think i will just slip on for now and wait for a full exhaust later...i appreciate the help...you wouldnt know your estimated 1/4 time or a 1/4 time you allrady ran eh?
 

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i havent ran it yet. knowing i just had it tuned back in Nov. and since then the bike has been being painted and polished along with the motor. with that power at the wheel it should be making around 100 at the crank. which is about 7 hp more then stock which dosent seem like much but it is.

it should run somewhere in the 11s at around 120s. but i havent raced a bike at that track so i might not get the time it should. but the speed i might be able. i just dont want to loop it off the line. come this spring when the bike is back together ill take it to the track to see what it does.
 

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Just have it jetted and dyno tuned, there are no questions then. Carbs are not hard to work with, they just take time.

Someone said the jets in the bike were 140s and they were running 122s so it makes stock richer. Not necessarily. It depends on who makes the jets and how they number them, also on the needle being used. A 160 jet with a big fat needle in it might flow less than a 110 with a needle that tapers down to a pin at the end. Thats why jetting is part art, not all science.
 
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