Am I too lean?

choneofakind · May 25th, 2011, 02:55 PM

I have a quick question on jetting. I'm confused because my issue covers a high rpm hesitation when there's small throttle inputs.

here's the scenario. I start from a stop, go WOT in first, then second and decide I'm going fast enough, so I shift to third and give it just enough gas to keep a constant speed. I get a stumble/ some surging (and the engine is turning about 9k) so I upshift again to 4th, and the surging is gone and the engine is at a little under 8k (give or take.)

So my question is, since I'm at a small throttle opening should I go with another shim on my needles since it's acting lean at a low throttle opening, or should I move up to 108 mains since the engine is acting lean at a high rpm?

for the record, the bike pulls hard all the way to redline, I shimmed with one washer on each needle and got rid of the 3-4k stumble, and i adjusted the idle mix to get the right responce when I blip the throttle. Did I not shim enough or do I need to go up to a bigger main jet?

as always, help is appreciated

edit
I think the title should say "needles or jets" rather than "am I too lean"

CC Cowboy · May 25th, 2011, 03:02 PM

check your plugs

kkim · May 25th, 2011, 04:03 PM

didn't we go through this before? I recommended 2 shims, but you decided to go with only one, if I remember correctly.

bottom line, try adding another shim and see if it improves.

choneofakind · May 25th, 2011, 07:10 PM

Yeah we did but 1 felt better at the time. I'll tear it apart and try 2 again I guess

sorry I was mainly confused about whether I should be first trying the needles or the main jets based on my symptoms because I was getting my slight lean spot at high rpm and small throttle openings.

kkim · May 25th, 2011, 07:17 PM

when I shimmed a pregen, I used 2 washers and the bike was completely stock. The owner really liked the out come. With your setup, I'd say 2 or maybe even 3 would work. try it and see.

May 25th, 2011, 02:55 PM	#1
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Am I too lean? I have a quick question on jetting. I'm confused because my issue covers a high rpm hesitation when there's small throttle inputs. here's the scenario. I start from a stop, go WOT in first, then second and decide I'm going fast enough, so I shift to third and give it just enough gas to keep a constant speed. I get a stumble/ some surging (and the engine is turning about 9k) so I upshift again to 4th, and the surging is gone and the engine is at a little under 8k (give or take.) So my question is, since I'm at a small throttle opening should I go with another shim on my needles since it's acting lean at a low throttle opening, or should I move up to 108 mains since the engine is acting lean at a high rpm? for the record, the bike pulls hard all the way to redline, I shimmed with one washer on each needle and got rid of the 3-4k stumble, and i adjusted the idle mix to get the right responce when I blip the throttle. Did I not shim enough or do I need to go up to a bigger main jet? as always, help is appreciated edit I think the title should say "needles or jets" rather than "am I too lean" Last futzed with by choneofakind; May 25th, 2011 at 07:20 PM.

May 25th, 2011, 03:02 PM	#2
CC Cowboy ninjette.org certified postwhore Name: Whodat Location: Ware Is.,MA Join Date: Jan 2009 Motorcycle(s): I pass the wind! Posts: A lot. MOTM - Mar '13, Jun '14	check your plugs __________________________________________________ If everything seems under control; you're just not going fast enough!

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May 25th, 2011, 04:03 PM	#3
kkim Join Date: Nov 2008 Posts: Too much.	didn't we go through this before? I recommended 2 shims, but you decided to go with only one, if I remember correctly. bottom line, try adding another shim and see if it improves.

May 25th, 2011, 07:10 PM	#4
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Yeah we did but 1 felt better at the time. I'll tear it apart and try 2 again I guess sorry I was mainly confused about whether I should be first trying the needles or the main jets based on my symptoms because I was getting my slight lean spot at high rpm and small throttle openings.

May 25th, 2011, 07:17 PM	#5
kkim Join Date: Nov 2008 Posts: Too much.	when I shimmed a pregen, I used 2 washers and the bike was completely stock. The owner really liked the out come. With your setup, I'd say 2 or maybe even 3 would work. try it and see.