Shimmed the needles, running slower

atl-ninja250 · July 14th, 2010, 04:33 PM

Okay here's my situation. Brand new bikes, fully broken in...

Installed a roaring toyz (area p) exhaust and shimmed the needles.

Shimming washer used is 3mm and 1mm thick.

Now when I accelerate, its like I gotta give it full throttle for it to go anywhere! I'm all the way up to 5,000 rpms before i get moving fast enough...

what could be the problem guys??

kkim · July 14th, 2010, 04:48 PM

how many washers did you use on each needle?

atl-ninja250 · July 14th, 2010, 05:05 PM

just one washer on each... you think i need another?

kkim · July 14th, 2010, 05:09 PM

http://www.ninjette.org/forums/showthread.php?t=9465

at least 2 or 3 with your present setup. I recommend pulling the snorkel out, too.

atl-ninja250 · July 14th, 2010, 05:29 PM

okay, gonna add another to it. im not so sure about the snorkle mod... i think ill leave it in there.

but im definitely going to add another washer. if same problem after that, ill try another.

thanks for the info

kkim · July 14th, 2010, 05:32 PM

let us know how it turns out... and be careful with those carb screws... they strip easily if you're not using a JIS screwdriver.

atl-ninja250 · July 14th, 2010, 05:51 PM

haha i know! stripped em already and replaced em

sons of beaches!

miks · July 15th, 2010, 12:05 AM

Yank that damn snorkle out mate, its craaaaazy without it! Good luck buddy.

atl-ninja250 · July 17th, 2010, 08:00 AM

SOOOOOO.... guess what?!! LOL

I put 2 more washers (3 total) on both of my bikes and both are now running too rich!!!

AHHHHHH lol.... gotta do it all over again! guess only 2 will work!

headshrink · July 17th, 2010, 01:43 PM

Quote:

Originally Posted by atl-ninja250

Shimming washer used is 3mm and 1mm thick.

what could be the problem guys??

The washers most are using are actually 0.5mm thick. So unless that was a typo, you're raising your needles twice as much as you may think.

kkim · July 17th, 2010, 01:49 PM

okay, but if the washers he is using are twice as thick, shouldn't the bike have run fine when he had one washer in there? ie... the same as 2x.5mm washers?

we need to see the washers you're using. pics, please?

headshrink · July 17th, 2010, 03:17 PM

Quote:

Originally Posted by kkim

okay, but if the washers he is using are twice as thick, shouldn't the bike have run fine when he had one washer in there? ie... the same as 2x.5mm washers?

we need to see the washers you're using. pics, please?

Absolutely.... I didn't read that closely, but I did want to make sure he was comparing "like kind," or was at least aware of the difference.

HKr1 · July 17th, 2010, 04:17 PM

Buy a nice exhaust..... then skimp out for washers, instead of a nice set of needles

atl-ninja250 · July 18th, 2010, 09:34 AM

yeah you're right! they are a bit larger. but for some reason 1 washer was just too lean! and 3 was way too rich. so now ive got 2 on there and its running a tiny bit too rich but not enough to really notice. no backfiring, just a tiny tiny bit of slowed acceleration. im pretty tired after doing this 3 times on both bikes!

so .... ill search around for a .25 washer and replace one of the two 1mm washers on there now and it should be perfect. until then... relaxing time

thanks for the help guys!!!

Ken08Ninja · July 18th, 2010, 10:38 AM

I used some 5x8x0.5MM Teflon washers from my RC monster truck. Your local hobby shop should have them in stock. They are TRAXXAS #1985.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJJ88

kkim · July 18th, 2010, 10:58 AM

Quote:

Originally Posted by atl-ninja250

they are a bit larger.

larger or thicker? any larger (overall diameter) and it can cause problems.

headshrink · July 18th, 2010, 11:12 AM

Quote:

Originally Posted by atl-ninja250

so .... ill search around for a .25 washer and replace one of the two 1mm washers on there now and it should be perfect. until then... relaxing time

thanks for the help guys!!!

0.5mm thickness is probably more common than 0.25mm. But as long as you know what you have, and are intentional about how much you are raising/lowering, you should be good. It takes several tries, as you are finding out. I'm on my twentieth, attempt to re-jet (probably more times than the average bear, but I'm chasing down some gremlins)!

atl-ninja250 · July 18th, 2010, 07:03 PM

well the size is perfect, they are just 1mm thick. :S

i need to get some .25mm or .50mm washers. these are 1mm thick

bdavison · July 18th, 2010, 08:08 PM

I really wish the exhaust manufacturers would stop telling people to shim the needles.

A carb doesnt just work off the main jet....a carb works in stages.
1. Idle to mid-range runs off the pilot jet.
2. Mid-range to WOT runs off the main jet.
There is overlap between each...for example once you hit mid-range, its going to being drawing fuel from both the pilot jet and the main jet.

Thats why shimming the needles is not the best way to do it, and the only correct way is by re-jetting the carb.

The needle you are shimming only richens the mixture once the bike enters the mid range. From idle to mid-range, the mixture is controlled by the pilot jet. Because of this...at your first 1/4 of throttle while the bike is pulling off the too small pilot jet...its starving for fuel and running lean until it gets to the point of pulling fuel from the main jet.

The correct way to fix this is to re-jet the pilot first, and THEN re-jet or shim the main.

kkim · July 18th, 2010, 08:47 PM

lol... AFAIK, I've not heard of one manufacturer that recommends shimming... the idea to do so came from us.

what you state is almost all true, but when you compare the gain you get from just shimming for pennies vs $100 for a jet kit, can you see the attraction?

to get the jetting perfect, yes, nothing but a jet kit and time will do, but to gain 75% of what a jet kit does and for pennies, I think you'll have a hard sell to everyone that wants to overcome that lean spot on the bottom from the too lean pilot circuit from the manufacturer.

g21-30 · July 19th, 2010, 04:44 AM

Just thought I would post a refresher on carb tuning. kkim and I love posting the following pic:

The picture was found in the following article, which should be mandatory reading for anyone new to carb tuning:

http://www.gadgetjq.com/keihin_carb.htm

bdavison · July 19th, 2010, 04:54 AM

Actually, that diagram is misleading...in reality, the pilot jet is working all the way to the 3/4 throttle mark, in somewhat of a sine wave. And the fact that it and the pilot screw get ignored by 90% of the garage tuners, is the reason for the myriad of poor results and lousy running engines.

g21-30 · July 19th, 2010, 05:03 AM

From the referenced article: "The primary purpose of the pilot system is to supply the mixture at idle. It continues to supply fuel throughout the entire throttle range, but after about 1/8 throttle is reached the MAIN SYSTEM starts to put out an increasing percentage of the total mixture up to full throttle."

atl-ninja250 · July 19th, 2010, 07:51 AM

Quote:

Originally Posted by g21-30

The picture was found in the following article, which should be mandatory reading for anyone new to carb tuning:

http://www.gadgetjq.com/keihin_carb.htm

Not working 4 me ...

dubojr1 · July 19th, 2010, 08:38 AM

Quote:

Originally Posted by atl-ninja250

Not working 4 me ...

Working fine for me with Internet Explorer 8.

July 15th, 2010, 12:05 AM	#8
miks I'm lovin' it. Name: Mike Location: Melb, Australia Join Date: Feb 2009 Motorcycle(s): '09 Black 250R Posts: A lot.	Yank that damn snorkle out mate, its craaaaazy without it! Good luck buddy. __________________________________________________ Son: When I grow up I want to ride a motorbike. Father: You can't do both son.

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July 14th, 2010, 04:33 PM	#1
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	Shimmed the needles, running slower Okay here's my situation. Brand new bikes, fully broken in... Installed a roaring toyz (area p) exhaust and shimmed the needles. Shimming washer used is 3mm and 1mm thick. Now when I accelerate, its like I gotta give it full throttle for it to go anywhere! I'm all the way up to 5,000 rpms before i get moving fast enough... what could be the problem guys??

July 14th, 2010, 04:48 PM	#2
kkim Join Date: Nov 2008 Posts: Too much.	how many washers did you use on each needle?

July 14th, 2010, 05:05 PM	#3
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	just one washer on each... you think i need another?

July 14th, 2010, 05:09 PM	#4
kkim Join Date: Nov 2008 Posts: Too much.	http://www.ninjette.org/forums/showthread.php?t=9465 at least 2 or 3 with your present setup. I recommend pulling the snorkel out, too.

July 14th, 2010, 05:29 PM	#5
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	okay, gonna add another to it. im not so sure about the snorkle mod... i think ill leave it in there. but im definitely going to add another washer. if same problem after that, ill try another. thanks for the info

July 14th, 2010, 05:32 PM	#6
kkim Join Date: Nov 2008 Posts: Too much.	let us know how it turns out... and be careful with those carb screws... they strip easily if you're not using a JIS screwdriver.

July 14th, 2010, 05:51 PM	#7
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	haha i know! stripped em already and replaced em sons of beaches!

July 17th, 2010, 08:00 AM	#9
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	SOOOOOO.... guess what?!! LOL I put 2 more washers (3 total) on both of my bikes and both are now running too rich!!! AHHHHHH lol.... gotta do it all over again! guess only 2 will work!

July 17th, 2010, 01:49 PM	#11
kkim Join Date: Nov 2008 Posts: Too much.	okay, but if the washers he is using are twice as thick, shouldn't the bike have run fine when he had one washer in there? ie... the same as 2x.5mm washers? we need to see the washers you're using. pics, please?

July 17th, 2010, 04:17 PM	#13
HKr1 IC2(SW) Name: Kerry Location: Pensacola Join Date: Nov 2008 Motorcycle(s): . Posts: A lot.	Buy a nice exhaust..... then skimp out for washers, instead of a nice set of needles

July 18th, 2010, 09:34 AM	#14
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	yeah you're right! they are a bit larger. but for some reason 1 washer was just too lean! and 3 was way too rich. so now ive got 2 on there and its running a tiny bit too rich but not enough to really notice. no backfiring, just a tiny tiny bit of slowed acceleration. im pretty tired after doing this 3 times on both bikes! so .... ill search around for a .25 washer and replace one of the two 1mm washers on there now and it should be perfect. until then... relaxing time thanks for the help guys!!!

July 18th, 2010, 10:38 AM	#15
Ken08Ninja ninjette.org member Name: Ken Location: NY Join Date: Dec 2008 Motorcycle(s): 08 Ninja 250R Candy Plasma Blue Posts: 129	I used some 5x8x0.5MM Teflon washers from my RC monster truck. Your local hobby shop should have them in stock. They are TRAXXAS #1985. http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJJ88

July 18th, 2010, 07:03 PM	#18
atl-ninja250 The Website Guy Name: Justin Location: Atlanta Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R & 650R Posts: 27	well the size is perfect, they are just 1mm thick. :S i need to get some .25mm or .50mm washers. these are 1mm thick

July 18th, 2010, 08:08 PM	#19
bdavison Wartown, USA Name: Bryan Location: Warner Robins, GA Join Date: Nov 2009 Motorcycle(s): 2009 Ninja 250R SE, 2007 Ninja 650R, and assorted other bikes Posts: A lot.	I really wish the exhaust manufacturers would stop telling people to shim the needles. A carb doesnt just work off the main jet....a carb works in stages. 1. Idle to mid-range runs off the pilot jet. 2. Mid-range to WOT runs off the main jet. There is overlap between each...for example once you hit mid-range, its going to being drawing fuel from both the pilot jet and the main jet. Thats why shimming the needles is not the best way to do it, and the only correct way is by re-jetting the carb. The needle you are shimming only richens the mixture once the bike enters the mid range. From idle to mid-range, the mixture is controlled by the pilot jet. Because of this...at your first 1/4 of throttle while the bike is pulling off the too small pilot jet...its starving for fuel and running lean until it gets to the point of pulling fuel from the main jet. The correct way to fix this is to re-jet the pilot first, and THEN re-jet or shim the main.

July 18th, 2010, 08:47 PM	#20
kkim Join Date: Nov 2008 Posts: Too much.	lol... AFAIK, I've not heard of one manufacturer that recommends shimming... the idea to do so came from us. what you state is almost all true, but when you compare the gain you get from just shimming for pennies vs $100 for a jet kit, can you see the attraction? to get the jetting perfect, yes, nothing but a jet kit and time will do, but to gain 75% of what a jet kit does and for pennies, I think you'll have a hard sell to everyone that wants to overcome that lean spot on the bottom from the too lean pilot circuit from the manufacturer.

July 19th, 2010, 04:44 AM	#21
g21-30 ninjette.org certified postwhore Name: Sam Location: Northern Virginia Join Date: Nov 2008 Motorcycle(s): Ninja 250R 2009 Posts: A lot.	Just thought I would post a refresher on carb tuning. kkim and I love posting the following pic: The picture was found in the following article, which should be mandatory reading for anyone new to carb tuning: http://www.gadgetjq.com/keihin_carb.htm

July 19th, 2010, 04:54 AM	#22
bdavison Wartown, USA Name: Bryan Location: Warner Robins, GA Join Date: Nov 2009 Motorcycle(s): 2009 Ninja 250R SE, 2007 Ninja 650R, and assorted other bikes Posts: A lot.	Actually, that diagram is misleading...in reality, the pilot jet is working all the way to the 3/4 throttle mark, in somewhat of a sine wave. And the fact that it and the pilot screw get ignored by 90% of the garage tuners, is the reason for the myriad of poor results and lousy running engines.

July 19th, 2010, 05:03 AM	#23
g21-30 ninjette.org certified postwhore Name: Sam Location: Northern Virginia Join Date: Nov 2008 Motorcycle(s): Ninja 250R 2009 Posts: A lot.	From the referenced article: "The primary purpose of the pilot system is to supply the mixture at idle. It continues to supply fuel throughout the entire throttle range, but after about 1/8 throttle is reached the MAIN SYSTEM starts to put out an increasing percentage of the total mixture up to full throttle."