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Discussion Starter #1
starting with the base settings recommended by the jet kit... i found it had good midrange and top end, slightly rough cruise and it was nice and snappy down low when cold but would get soft pretty quickly...

that was with 155/158 main jets, needles set to 3.5 clips from the top, 16mm float height and 2.5 turns out on the pilot screws

using the factory pro tuning guide, ive taken the pilot screws out a turn and have been adding 1mm to the float height at a time (so lowering the fuel level ~1mm) and it just keeps getting better and better down low! so far im on 20mm float height and about to try 21mm, as performance still suffers slightly at low revs as the bike warms up (thus it must be rich?) but its fine in the midrange and top end...

ive been going up a size on the mains every 2mm or so ive raised the float height to compensate

ive experimented with smaller jets and a higher fuel level but nothing has worked as well as this...

question is, with stock standard float height at 13mm (+/- 2mm) and factory recommending 16mm .... am i going the wrong way here? its a pretty big difference and the tang on the floats almost cant bend any more! [B)] anybody ever heard of such a low fuel level being ideal?

edit: bike is a 1998 C1 with full akra system, +4 degree advancer, factory pro jetkit and stock air filter with the mesh removed. B, E or F carb settings are completely different
 

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wouldnt a higher float height mean more fuel. the further the float gets up the more fuel it takes to get it there? i have no idea about the carb ur dealing with, but it seems to lower the float would be less fuel, not more. or maybe im not understanding where these measurements are being takin. im sure thats prob it, cuz carbs aint my thing.... but also fuel level in the float shouldnt have anything to do with how the bike runs. unless u are sucking the float dry.....[?][?] damn..now i just confused myself
 

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You measure float height upside down so it's backward from what you think.
I would try leaner pilot jets. My bike is stumbling off idle but I need to go richer. These jets and needles overlap what range they affect so you don't get a light switch response when coming off the idle or into the main jet.
 

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I also think you could drop the needle one more slot so it goes furhter into the main jet.A thicker taper near the bottom would work also. I have an excelent source for jets and info.
 

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Discussion Starter #5
thanks, i might look into that


it seems i was chasing my tail, lowering the fuel level to try to lean out the bottom end and then upping the mains to compensate for the leaner top end... and about 20.5mm is the absolute lowest fuel level a C model 9R can have [B)] im now back to about 17mm float height, 158/155 mains and needles still on 3.5 clips, but having some luck turning the pilot screws in .... i might look into a leaner pilot jet? tho ive only ever heard of people needing a richer pilot jet (40's up from 38) on these bikes...

it might explain why even tho ive got perfectly balanced carbs ive never had a good idle, and often get stumbling/missing on light cruise (tho its still strong in the first 1/8th of the throttle)


maybe easier to throw in a BMC or K&N and tune from there, they lean things out quite a bit so i hear (even if they dont flow any more in the real world?)
 

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You know you need to go richer if using the choke helps. Leaner would require a jet change because you don't want to change your overall mixture, just at or off idle.
I just got my pilot jets today. Going in with some 42s and will tune with the screw if it's too much.
 

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Discussion Starter #9
i have 38's already (stock for a C model) so i guess 36 would be the next size down


im not having any luck going any leaner than about 1.75-2.0 screws out on the pilots, so i dont think it would really help having a smaller pilot jet... but keep in mind im running a really low fuel level as it is...

i just cant be bothered with this any more, but ive been ripped by mechanics here who know less than me about tuning carbs :(
 
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