5-gas theory, jetting and air box question

max427 · October 11th, 2011, 09:49 AM

I know there its already 40 threads on these topics, I did search and read and read, checked out the wiki but still have a few questions.
First off, my girlfriends ninja has always had low rpm stalling issue which I just thought was user error until yesterday it took 10 minutes to warm up before it would stay running during take off. I never ride the bike much but it def does take a lot of rpm and slip to get it moving smoothly.
Started checking things yesterday, bike has 8500 miles witj original plugs and never had carbs cleaned. Pulled out airbox and found it full of dirty water, filter clogged and a good size hole on the right side bottom like someone pryed it out and broke it. Going to replace with k&n dual filter pod styleand replace plugs, shim needles for low rpm driveabilityand sync carbs. Now:
What plugs should I use?
After sync and shim will I have enough adjustment on carb to keep it from running to lean?
In other words is it absolutely necessary to rejet or can I get away without it? Bike is otherwise stock
Also I have an emissions dyno at work I can use to check af ratio but it wont be very accurate, anyone have experience adjusting carb using 5 gas analyzer? Im used to cars and trucks that indicate lean by high nox emissions and high co, same basic principles apply here?
Thank you guys so much- max

Live2ride · October 11th, 2011, 10:09 AM

I tuned mine with the Ol' butt dyno while shimming and removing the airbox. Considering the bike has 8,500 miles, have you had the 7,500 mile service performed on the bike yet? Adjusting the valves could help with warming up the bike; It did with my bike.

All shimming is different but I'd suggest starting with 2 washers on each needle and test ride it; if it's running too rich, as it did on mine, you can remove the airbox snorkel to even out the fuel to air ratio. After shimming, my 250 has warmed up faster and has a much smoother throttle control in low rpm's.

DaBlue1 · October 11th, 2011, 10:51 AM

Quote:

Originally Posted by max427

... I never ride the bike much but it def does take a lot of rpm and slip to get it moving smoothly.
Started checking things yesterday, bike has 8500 miles witj original plugs and never had carbs cleaned. Pulled out airbox and found it full of dirty water, filter clogged and a good size hole on the right side bottom like someone pryed it out and broke it. Going to replace with k&n dual filter pod style and replace plugs, shim needles for low rpm driveability and sync carbs. Now:
What plugs should I use?
After sync and shim will I have enough adjustment on carb to keep it from running to lean?
In other words is it absolutely necessary to rejet or can I get away without it? Bike is otherwise stock

I'm assuming the bike is used. The Ninja has little HP down low, so getting the rpms up to about 2.5-3k to launch is normal. How many rpms does it require to get moving? Being a cold blooded bike it does require a lil time to warm up, but if tuned properly, warm ups can be short.

If your airbox was full of water, then the airbox drain tube is clogged.
What has a good size hole? the filter or airbox? if the airbox then you are getting a little too much air. if it is an oblong hole next to the air filter cover then that is the hole where the snorkel was removed. Can you be more specific?

Putting on pod filters will definitely allow way more air into the intake, so you will have to add more fuel by rejetting if you want it to perform properly.
If using the airbox you can shim and remove the snorkel (if it has one) and be fine provided the air filter and carbs are clean. You can use stock plugs and be fine.(NGK CR8E or ND U24ESR-N) A valve inspect/adjustment is also due as well.

Jojah17 · October 11th, 2011, 11:22 AM

These bikes run lean right out of the box. You're going to be leaning it out a good bit more by stripping the airbox and putting on Pods. I ran with Pods and shimmed needles for a bit and was very disappointed with performance. When I rejetted (just the mains with no jet kit or anything) I was very happy with how the bike responded. Shimming helps a bit but not nearly as much as rejetting. After rejetting- the bike warms up much faster and has a lot more useable power across the board (granted its still not alot in the low end due to being a 250). I'd say after putting in the work to slap in pods and tune the carbs there is no reason to not rejet.

max427 · October 11th, 2011, 04:42 PM

The hole is about 1/4inch wide, inch long, like someone put a prybar through it. Also i forgot to mention i found two of the air box screws in the air box, before the filter (thankfully). Someone was in here before and didnt really give a sh*t.

Ok so i tried to absorb what you guys said and think this is the route i'll go, at least at first:
Repair the hole in the airbox, remove the snorkel and get new filter (you guys recommend stock replacement or aftermarket?)
Replace plugs
Shim needles (2 washers to start) then sync the carbs.
With that being said, think i will be able to tune the carbs to run right without rejetting? Im not so much concerned with max power or even high end power, i just want a setup that is going to make standing starts and warm up a little easier.

Jojah17 · October 11th, 2011, 05:07 PM

Yeah you should be fine in that case. Go aftermarket with the filter...washable is always nice and they arent expensive. Shim the needles up 2-3 if u remove the klee air system. Should be good to go after that.

max427 · October 11th, 2011, 06:50 PM

Going to go with Uni filter, is it likely that local parts houses will have this filter or am i going to have to order it offline? Thanks!

DaBlue1 · October 12th, 2011, 05:53 AM

Quote:

Originally Posted by max427

Going to go with Uni filter, is it likely that local parts houses will have this filter or am i going to have to order it offline? Thanks!

I have yet to find an aftermarket air filter on the shelf anywhere for the 250 Ninja. Even the dealers did not have an OEM one in stock. You may have to order the one you want.
With the UNI filter make sure you specifically get one for the 2008-2010 Ninja 250r and not just one that says EX250 or Ninja 250. They are two different models.

max427 · October 12th, 2011, 07:19 AM

factory pro jet kit is listed only up to 2007 on their website, same thing for 2008? Could i just buy 2 of each 108, 110, 112 jets and work with that for a rejet? thanks again guys!

Jojah17 · October 12th, 2011, 07:29 AM

I thought you weren't rejetting? But yes, thats what I did.

Jojah17 · October 12th, 2011, 08:04 AM

http://www.jetsrus.com/a_jet_kit_str...50R_Ninja.html

max427 · October 12th, 2011, 08:13 AM

Quote:

Originally Posted by Jojah17

I thought you weren't rejetting? But yes, thats what I did.

haha yesi am apparently very fickle. if i can increase the bikes driveability at low rpm then im all for that, installing the aftermarket pods will make carb work a lot easier, i figure might as well do it. after i put on the k&n pod filter is the bike even going to be rideable or so lean it wont run?
btw thanks for link!

Jojah17 · October 12th, 2011, 08:25 AM

It will be rideable but it won't be enjoyable. Also, running lean is bad for the motor's longevity. Honestly, my first post may have sounded convuluted and Im sorry for that....throwing PODs on,removing kleen air system, rejetting and shimming will net you mainly top end power. When i said power across the board I was meaning to compare Pods + shims to pods+shims+jetting. I'm happy with PODs...they sound cool, are cheap to replace, and get me a little more oomph on the top end. Rejetting just the mains is super easy (and cheap) and doesn't even require pulling the carbs from the bike. I've got 110's in mine now and I've got Pods and Area P exhaust.

bob138 · October 14th, 2011, 02:13 PM

I'd:

-Fix the hole in the box.
-Change the air filter
-Shim the needles
-Change the plugs
-Remove the snorkel from the airbox

Then ride it around for a bit. See what you think. I only shimmed, and pulled the snorkel and it was like night and day on the low end. After that, maybe re-gearing. I've heard it really adds that little extra to the gears that you are looking for. I thought it was even a fairly simple change, like front sprocket only and viola.

bob

rockNroll · October 14th, 2011, 06:54 PM

Quote:

Originally Posted by bob138

I'd:

-Fix the hole in the box.
-Change the air filter
-Shim the needles
-Change the plugs
-Remove the snorkel from the airbox

Then ride it around for a bit. See what you think. I only shimmed, and pulled the snorkel and it was like night and day on the low end. After that, maybe re-gearing. I've heard it really adds that little extra to the gears that you are looking for. I thought it was even a fairly simple change, like front sprocket only and viola.

bob

this

max427 · October 16th, 2011, 08:40 AM

I guess i am stubborn, i installed the k&n pod, shimmed carb needles (2 M3 washers a piece) and fired the bike up. took a while to finally fire up, i guess because carb was drained, however once it did start it seemed to run pretty well idling with choke on.
Went to take it for a test ride and it just dies. start letting out the clutch and giving it some gas and it just wont rev up then dies no matter what i do. I tried to attach a video but file too large.
also noticed when choke is on the bike revs to 6k, seemed high. Anyway, what should i try first to fix this?

max427 · October 16th, 2011, 08:42 AM

Also i forgot to mention i have the large hose from the kleen air system open right now, i know it used to run into airbox, i need to get another breather for that. i have crankcase vent on a breather. that wouldnt cause any problems though, correct?

video: http://www.youtube.com/watch?v=R7fWfR6X0N0

Cuongism · October 16th, 2011, 03:11 PM

If you switched to pods, you're gonna need larger jets or it won't rev past a certain point. A lot more air is introduced so you need to add fuel by using bigger main jets. If you're also re-using the stock intake runners, make sure they're not getting "squished."

http://www.ninjette.org/forums/showthread.php?t=11899

October 11th, 2011, 09:49 AM	#1
max427 ninjette.org member Name: Max Location: philadelphia Join Date: Jul 2011 Motorcycle(s): 09' Ninja 500r 08' Ninja 250r Posts: 17	5-gas theory, jetting and air box question I know there its already 40 threads on these topics, I did search and read and read, checked out the wiki but still have a few questions. First off, my girlfriends ninja has always had low rpm stalling issue which I just thought was user error until yesterday it took 10 minutes to warm up before it would stay running during take off. I never ride the bike much but it def does take a lot of rpm and slip to get it moving smoothly. Started checking things yesterday, bike has 8500 miles witj original plugs and never had carbs cleaned. Pulled out airbox and found it full of dirty water, filter clogged and a good size hole on the right side bottom like someone pryed it out and broke it. Going to replace with k&n dual filter pod styleand replace plugs, shim needles for low rpm driveabilityand sync carbs. Now: What plugs should I use? After sync and shim will I have enough adjustment on carb to keep it from running to lean? In other words is it absolutely necessary to rejet or can I get away without it? Bike is otherwise stock Also I have an emissions dyno at work I can use to check af ratio but it wont be very accurate, anyone have experience adjusting carb using 5 gas analyzer? Im used to cars and trucks that indicate lean by high nox emissions and high co, same basic principles apply here? Thank you guys so much- max

October 11th, 2011, 10:09 AM	#2
Live2ride ninjette.org certified postwhore Name: Cody Location: NoVa Join Date: Jan 2011 Motorcycle(s): 06 yzf r6r previously: 09 ninja 250r, black 07 zx6r Posts: A lot.	I tuned mine with the Ol' butt dyno while shimming and removing the airbox. Considering the bike has 8,500 miles, have you had the 7,500 mile service performed on the bike yet? Adjusting the valves could help with warming up the bike; It did with my bike. All shimming is different but I'd suggest starting with 2 washers on each needle and test ride it; if it's running too rich, as it did on mine, you can remove the airbox snorkel to even out the fuel to air ratio. After shimming, my 250 has warmed up faster and has a much smoother throttle control in low rpm's. __________________________________________________

October 14th, 2011, 02:13 PM	#14
bob138 ninjette.org member Name: Bob Location: Centreville va Join Date: Sep 2010 Motorcycle(s): 1991 EX500 , 2009 250r Posts: 130	I'd: -Fix the hole in the box. -Change the air filter -Shim the needles -Change the plugs -Remove the snorkel from the airbox Then ride it around for a bit. See what you think. I only shimmed, and pulled the snorkel and it was like night and day on the low end. After that, maybe re-gearing. I've heard it really adds that little extra to the gears that you are looking for. I thought it was even a fairly simple change, like front sprocket only and viola. bob __________________________________________________ My EX500 Build My 09 250R Build

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October 11th, 2011, 11:22 AM	#4
Jojah17 ninjette.org member Name: Ben Location: Atlanta Join Date: Feb 2011 Motorcycle(s): 2008 Honja Posts: 171	These bikes run lean right out of the box. You're going to be leaning it out a good bit more by stripping the airbox and putting on Pods. I ran with Pods and shimmed needles for a bit and was very disappointed with performance. When I rejetted (just the mains with no jet kit or anything) I was very happy with how the bike responded. Shimming helps a bit but not nearly as much as rejetting. After rejetting- the bike warms up much faster and has a lot more useable power across the board (granted its still not alot in the low end due to being a 250). I'd say after putting in the work to slap in pods and tune the carbs there is no reason to not rejet.

October 11th, 2011, 04:42 PM	#5
max427 ninjette.org member Name: Max Location: philadelphia Join Date: Jul 2011 Motorcycle(s): 09' Ninja 500r 08' Ninja 250r Posts: 17	The hole is about 1/4inch wide, inch long, like someone put a prybar through it. Also i forgot to mention i found two of the air box screws in the air box, before the filter (thankfully). Someone was in here before and didnt really give a sh*t. Ok so i tried to absorb what you guys said and think this is the route i'll go, at least at first: Repair the hole in the airbox, remove the snorkel and get new filter (you guys recommend stock replacement or aftermarket?) Replace plugs Shim needles (2 washers to start) then sync the carbs. With that being said, think i will be able to tune the carbs to run right without rejetting? Im not so much concerned with max power or even high end power, i just want a setup that is going to make standing starts and warm up a little easier.

October 11th, 2011, 05:07 PM	#6
Jojah17 ninjette.org member Name: Ben Location: Atlanta Join Date: Feb 2011 Motorcycle(s): 2008 Honja Posts: 171	Yeah you should be fine in that case. Go aftermarket with the filter...washable is always nice and they arent expensive. Shim the needles up 2-3 if u remove the klee air system. Should be good to go after that.

October 11th, 2011, 06:50 PM	#7
max427 ninjette.org member Name: Max Location: philadelphia Join Date: Jul 2011 Motorcycle(s): 09' Ninja 500r 08' Ninja 250r Posts: 17	Going to go with Uni filter, is it likely that local parts houses will have this filter or am i going to have to order it offline? Thanks!

October 12th, 2011, 07:19 AM	#9
max427 ninjette.org member Name: Max Location: philadelphia Join Date: Jul 2011 Motorcycle(s): 09' Ninja 500r 08' Ninja 250r Posts: 17	factory pro jet kit is listed only up to 2007 on their website, same thing for 2008? Could i just buy 2 of each 108, 110, 112 jets and work with that for a rejet? thanks again guys!

October 12th, 2011, 07:29 AM	#10
Jojah17 ninjette.org member Name: Ben Location: Atlanta Join Date: Feb 2011 Motorcycle(s): 2008 Honja Posts: 171	I thought you weren't rejetting? But yes, thats what I did.

October 12th, 2011, 08:04 AM	#11
Jojah17 ninjette.org member Name: Ben Location: Atlanta Join Date: Feb 2011 Motorcycle(s): 2008 Honja Posts: 171	http://www.jetsrus.com/a_jet_kit_str...50R_Ninja.html

October 12th, 2011, 08:25 AM	#13
Jojah17 ninjette.org member Name: Ben Location: Atlanta Join Date: Feb 2011 Motorcycle(s): 2008 Honja Posts: 171	It will be rideable but it won't be enjoyable. Also, running lean is bad for the motor's longevity. Honestly, my first post may have sounded convuluted and Im sorry for that....throwing PODs on,removing kleen air system, rejetting and shimming will net you mainly top end power. When i said power across the board I was meaning to compare Pods + shims to pods+shims+jetting. I'm happy with PODs...they sound cool, are cheap to replace, and get me a little more oomph on the top end. Rejetting just the mains is super easy (and cheap) and doesn't even require pulling the carbs from the bike. I've got 110's in mine now and I've got Pods and Area P exhaust.

October 16th, 2011, 08:40 AM	#16
max427 ninjette.org member Name: Max Location: philadelphia Join Date: Jul 2011 Motorcycle(s): 09' Ninja 500r 08' Ninja 250r Posts: 17	I guess i am stubborn, i installed the k&n pod, shimmed carb needles (2 M3 washers a piece) and fired the bike up. took a while to finally fire up, i guess because carb was drained, however once it did start it seemed to run pretty well idling with choke on. Went to take it for a test ride and it just dies. start letting out the clutch and giving it some gas and it just wont rev up then dies no matter what i do. I tried to attach a video but file too large. also noticed when choke is on the bike revs to 6k, seemed high. Anyway, what should i try first to fix this?

October 16th, 2011, 08:42 AM	#17
max427 ninjette.org member Name: Max Location: philadelphia Join Date: Jul 2011 Motorcycle(s): 09' Ninja 500r 08' Ninja 250r Posts: 17	Also i forgot to mention i have the large hose from the kleen air system open right now, i know it used to run into airbox, i need to get another breather for that. i have crankcase vent on a breather. that wouldnt cause any problems though, correct? video: http://www.youtube.com/watch?v=R7fWfR6X0N0

October 16th, 2011, 03:11 PM	#18
Cuongism ninjette.org certified postwhore Name: Cuong Location: San Diego Join Date: Jul 2010 Motorcycle(s): 2008 Ninja 250r, 2007 Daytona 675 Posts: A lot.	If you switched to pods, you're gonna need larger jets or it won't rev past a certain point. A lot more air is introduced so you need to add fuel by using bigger main jets. If you're also re-using the stock intake runners, make sure they're not getting "squished." http://www.ninjette.org/forums/showthread.php?t=11899