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Selecting Main Jet and Needle Clip Setting
http://www.kawi2strokes.com/forum/viewtopic.php?f=14&t=8342		 Page 3 of 3
Author:  Zambia [ Thu Nov 07, 2019 8:36 am ]
Post subject:  Re: Selecting Main Jet and Needle Clip Setting
I couldn't quite get the gist of it either - I think your observation is correct Joe.. but knuckle draggers like me are always looking for RPM and throttle position info. Not used to flow bench numbers. Can a chart also be made that shows what happens in a scenario like that when you swap pilots? Or jet needles?
Author:  demus [ Thu Nov 07, 2019 1:06 pm ]
Post subject:  Re: Selecting Main Jet and Needle Clip Setting
I know I will get lambasted for this (even if no one says so :mrgreen: )
I have always tuned (close on the pilot and needle first of course) the main jet first "ISH' then went back and and adjusted the the other circuits slightly.
Every time I have tried to follow the carb tuning guide I get it all screwed up, if I do it my way it seems to go better for me......I never can follow directions :lol:

Just to be clear Im not saying tune main first, just that I try to get a good main jet as soon as possible then tune the rest.
Author:  ALTERED IMAGE [ Fri Nov 08, 2019 7:08 am ]
Post subject:  Re: Selecting Main Jet and Needle Clip Setting
To clarify the results on the flow bench.

At the far right is max. flow at WOT Far left is about 19% throttle position.

At WOT it is obvious, as most know, how much the main jet contributes to the flow to the venturi which I measure with a mass flow meter(air) .

What is interesting is the amount of effect of the main closer to idle.

To answer the question: Yes the bigger main comes on sooner at part throttle.

It is not a purely geometric relationship as the spreadsheets suggest. This is a system of 2 jets in series and each has an effect on the other.

Needle jet partially blocked by the needle(variable) and main jet(fixed).

cliff EDITED-230MAIN JET USED ON -3 CLIP POSITION DELETED SORRY

Attachment:
280mj.jpg
Author:  ALTERED IMAGE [ Thu Sep 09, 2021 7:50 am ]
Post subject:  Re: Selecting Main Jet and Needle Clip Setting
This one shows clip position DOES have influence on mains and 1/2 throttle
Author:  H2RTuner [ Thu Sep 09, 2021 1:57 pm ]
Post subject:  Re: Selecting Main Jet and Needle Clip Setting
Yes, needle clip position does have influence from 1/4 to full throttle operation

Dyno/Flow Bench is useless for final tuning, no-one has ever driven/ridden a dyno, or flow bench around the block, or race track

"Seat Of The Pants" Dyno is the ONLY one that gets it right, EVERY TIME
Author:  ALTERED IMAGE [ Sat Sep 11, 2021 4:56 am ]
Post subject:  Re: Selecting Main Jet and Needle Clip Setting
True Dave,

This was just an experiment to get an overall interaction of the circuits, not for tuning on the spec. bike.

cliff
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