November 11th, 2008, 08:56 PM | #1 |
Join Date: Nov 2008 Posts: Too much.
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Shimming the Carb Needles... Is it for You?
Shimming the needles, raising the needle jet, the washer trick… whatever you want to call it, it works for our bikes. I would rate this mod as the top DIY one should consider doing to their bike, especially if you’re a newer rider and trying to get comfortable riding it. It really does make the bike easier to ride and boosts confidence, two things any new rider can use.
While this trick has been used on the previous generation 250s, this is written specifically for the new gen (08-09) 250R. Most of the info, though, is general enough to apply to the pregens. Many seem confused as to what it does and why one would even consider this mod. Still others worry if their bike really needs it and if they are capable of doing it. I hope this post will help clear up a lot of questions and doubts on what the symptoms are of a bike that needs it, why it’s the way it is and how to remedy it. So, if after you read this post and want to give it a try, post your questions here and we’ll see what we can do to help. Also, if you have done this mod and like or hate the results, please post your comments here so all that are considering doing this will have adequate feedback to decide for themselves to do this or not. I just thought it was time to simplify the whole “shimming” decision making process. Hope this proves useful to those wanting answers. 1- Who needs it and what will it do for my bike? Shimming the needles will get rid of a nasty lean spot coming right off idle. If your bike stalls, hesitates, hacks or coughs when you are trying to pull off from a stop, you could use shimming. Also, if your bike needs to have the choke on to start it, when the engine is stone cold, and needs the choke on for long periods of time, you should shim. A great DIY on how to shim is located here… http://www.kawiforums.com/showthread.php?t=105901 2- What does this all do? Well, if your bike is lean, shimming will make the bike seem like it has more power at the very bottom end of the rev range. (2-5K rpm) The power band seems “fatter” which leads to an easier to ride bike. If you are a beginning rider and feel the bike is hard to ride because of difficulty of getting the bike off cleanly from a stop, shimming will do wonders for your riding confidence. Start offs will seem like the bike just gets up and rides away on its own. No kidding… after shimming (if your bike is one that needs it), it will literally transform your engine power characteristics. 3- Why is my bike like this from the factory… is something wrong with it? Kawasaki designed the 250R with fuel economy and emissions controls in mind when they selected the jetting specs. That they went with the most conservative settings to obtain good advertising results flies directly against the very market these bikes were designed for… namely, the beginning rider. The lean settings make the bike very anemic down low in the rev range which results in a very hard to control power band for the neophyte rider. Instead of having a lot of power right when you let out the clutch from a stop, the lean settings make the bike hard to negotiate cleanly from a stop. New riders have a hard enough time coordinating throttle and clutch engagement. The weak low end power just makes it that much harder for the beginning rider to pull off clean take offs, not to mention worrying about stalling the bike in the middle of an intersection. My take on this is that the bikes are lean due to incorrect settings of the idle mixture screws at the factory. Whoever is doing them is not setting them correctly... and to make it worse, they are not setting them incorrectly consistently. This means some bikes are waaaayy too lean, some sorta lean, others just right and still others (very few) rich. How many washers you will need will depend on a couple of things. The thickness of the washers you use, the setting of your particular bike's mixture screws from the factory as well as other factors that normally affect jetting. (temp, altitude and humidity) Take all this into account and it is easy to see why there are no golden rules as to how many washers will work best for all bikes. As is the case with all jetting work, experimentation is key to obtaining jetting perfection. I will say, while you have improved your jetting from stock by using the washers, it is far from perfect, but certainly worlds better than it was from off the showroom floor. For many, this will be all they will ever need to do to improve the jetting to make theirs an enjoyable, friendly bike. 4- Come on… at least give me a place to start!! Okay, okay… These are some very general rule of thumb washer numbers. Expect to have to do this a couple of times if you are not satisfied with the recommendations… 1 washer for a completely stock bike. 1-2 washers for an aftermarket can or system 2-3 washers for an aftermarket system or can with the snorkel removed 5- Some caveats before deciding you should do this… Not all people who have shimmed their bikes have met with success. There have been a few that actually installed the washers and the bike ran like crap. They ended up taking the washers back out and their bikes run fine without any washers to this day. Remember step #1? Their bikes never stalled from stops and in fact needed little or no choke at start up. These bikes are the few that were set right or a bit rich from the factory. You need to determine if the situations in #1 describe your bike. If it does, it’s a safe bet shimming will improve your bike. If you have never worked on a bike before and would like to do this mod, read the DIY link I posted. Read it (the entire thread!) and understand it before you start tearing your bike apart. Have all the suggested tools available, especially the long #2 Phillips screwdriver. It does take some degree of mechanical skill to accomplish this task and some of the parts you will be dealing with are quite delicate. Just be clean and orderly when you work and you should do fine. Do one carb at a time as you don’t want to mix parts up between the left and right carb as some parts are different between the two. Set aside some time to do this. If it’s your first time tearing the bike apart, plan on 4 hours. Personally, I usually allow double the time on any new project I work on, so for this I would put aside 8 hours just in case something should go wrong. If there are any questions, please post them in this thread and the members of the board who have done this before will be more than happy to answer your questions and/or sooth your fears. |
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November 16th, 2008, 09:40 AM | #2 |
ninjette.org certified postwhore
Name: Kim
Location: mundo de ensueño
Join Date: Nov 2008 Motorcycle(s): '08 250 Posts: A lot.
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Worked for me!
I followed kkim's advice, and I now have a bike that is much nicer to ride! She was very 'surgey' especially around 4.5-5 k, which is where I would often find myself on back roads.... she was also unpredictable at starts- bogging and then kicking in, which made me rather nervous... I threw a washer in, and not much trouble after that!
Now that it's gotten cooler, it was starting to have issues again, so we threw on a second washer, and all of my troubles went away. |
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November 19th, 2008, 07:38 PM | #3 |
Da Duckman
Name: Duckman
Location: Pensacola, FL
Join Date: Nov 2008 Motorcycle(s): '08 250R, '06 Chopper, '80 Puch Magnum II, '01 SV650, '99 CR250/CR500AF Sportbike. '02 CRF450/CR500AF Dirt Posts: 480
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I've got 3 washers under mine with pod filters and 120 Keihin jets and Area-P exhaust!
Runs great! Recommended! |
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November 23rd, 2008, 11:43 PM | #4 |
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Name: Nick
Location: Occoquan, VA
Join Date: Nov 2008 Motorcycle(s): '09 Ninja 250R Posts: 518
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I recommend this also.
After a week of having the bike, I put the first set of washers on. This helped so much in stopping the bogging and made a much more solid running bike. The temperatures were around 50-70 degrees at the time and it was great for about a month, but when it starting getting a little colder I found it going back to the original problem so I threw another set of washers on. I'm now riding in sub-30 degree weather without any trouble at all. By far, this is the best mod I've done! |
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March 13th, 2009, 05:03 PM | #5 |
Live 2 Ride Forced 2 Work
Name: Chris
Location: Guam
Join Date: Mar 2009 Motorcycle(s): 2008 RED 250r Posts: 386
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Im seriously considering this mod but I dont really have any stalling or bogging problems right nowand the coldest it ever gets here is in the low 70s. I'll probably wait until I get a new exhaust and then add a few washers. If I were to get an Area P full exhaust- would shimming the needles be enough r would I need a jet kit?
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March 13th, 2009, 05:09 PM | #6 |
Join Date: Nov 2008 Posts: Too much.
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shimming would be perfectly fine if you took the time to fine tune the carb with the correct number of shims. I was running around with my area P and washers for months before I decided to rejet. The bike ran well. in fact if you ever watched my uphill vid, that was done with the AP and washers in the carbs.
I only decided to install a jet kit because I removed my airbox and had to rejet completely at that point, anyway. |
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March 13th, 2009, 10:01 PM | #7 |
Live 2 Ride Forced 2 Work
Name: Chris
Location: Guam
Join Date: Mar 2009 Motorcycle(s): 2008 RED 250r Posts: 386
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cool. Thanks- I think I'll hold of for another month or so when I get my exhaust and then I'll shimmy the needles.
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March 22nd, 2009, 03:07 PM | #8 |
Join Date: Nov 2008 Posts: Too much.
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March 22nd, 2009, 03:16 PM | #9 |
Da Duckman
Name: Duckman
Location: Pensacola, FL
Join Date: Nov 2008 Motorcycle(s): '08 250R, '06 Chopper, '80 Puch Magnum II, '01 SV650, '99 CR250/CR500AF Sportbike. '02 CRF450/CR500AF Dirt Posts: 480
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March 25th, 2009, 11:31 PM | #10 | |
ninjette.org member
Name: Danny
Location: Houston, TX
Join Date: Feb 2009 Motorcycle(s): 2009 Kawasaki Ninja 250r Posts: 42
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Quote:
Would shimming make the choke not necessary at cold start ups? |
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March 26th, 2009, 12:08 AM | #11 |
Join Date: Nov 2008 Posts: Too much.
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shimming doesn't negate the use of the choke. It will aide the bike to warm up quicker and enhance the power at low and the midrange.
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March 27th, 2009, 01:33 PM | #12 |
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Name: Danny
Location: Houston, TX
Join Date: Feb 2009 Motorcycle(s): 2009 Kawasaki Ninja 250r Posts: 42
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Hi, I just got me a Yoshimura Slip on. How many washers do you think I should use? Also, do I need more washers if I remove the snorkel? Thanks!
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March 29th, 2009, 03:54 PM | #13 |
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Name: Tim
Location: Portland, OR
Join Date: Dec 2008 Motorcycle(s): 2009 SE Ninja 250R Posts: 796
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Well it seems most people have success with 2. I would start off with that, though you might need 3 to balance the slip on. That's the route I will be taking anyways once it's warm enough that my hands don't shake and ruin the carbs/needles
Has anyone noticed a huge drop in fuel economy? I wanna know how "rich" shimming actually makes it. |
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March 29th, 2009, 04:01 PM | #14 |
Join Date: Nov 2008 Posts: Too much.
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I agree, start with 2 and if you think the bike could benefit more, add another.
You take a hit in fuel economy, but you do end up with an easier to ride bike. I'd say roughly 50mpg after shimming depending on how liberal you are with the throttle. |
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March 29th, 2009, 04:17 PM | #15 |
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Name: Tim
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March 29th, 2009, 04:20 PM | #16 |
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Just ride the bike as you need to, to keep up with traffic. That should be plenty to seal the rings. No need to ring it's neck all the time, though it is fun.
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March 29th, 2009, 05:25 PM | #17 |
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Name: David
Location: Wellington, New Zealand
Join Date: Dec 2008 Motorcycle(s): 08 Ninja 250R in Green! (Sold) Now 2011 Triumph Daytona 675 SE Posts: 564
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I myself have not noiced the fuel economy difference at all... Before doing any engine mods and after the engine had a few 1000kms on it I would get 340km out and fill up with about 14L, I am still getting that with Dynojet jet kit 98 main needle, Areap Full QC and snorkell out. A few fills ago I got 350km and I only filled with 13.5L... I guess it depends on the right hand, though I have been going harder with the mods
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2008 GREEN Kawasaki Ninja 250R. AreaP Quiet Core Carbon Fibre : 8000k HIDs : Dynojet Jet kit : Double Bubble Windscreen |
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April 11th, 2009, 08:18 PM | #18 | |
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Name: patricK
Location: San Jose, CA--BAY AREA!
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Quote:
I too seem to get about 50mpg with mixed city and highway riding. |
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April 15th, 2009, 06:20 PM | #19 |
Normal people scare me!
Name: Brian
Location: West of Atlanta
Join Date: Jan 2009 Motorcycle(s): 08 Ninja 250r Posts: 17
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No washers on mine. I don't have any hesitation at start up. I use the choke for a few blocks and shut if off. After starting it the first time of the day, the choke really is not needed to start the rest of the day.
In my case, I have not even considered doing this mod.
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April 15th, 2009, 06:23 PM | #20 | |
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Quote:
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April 15th, 2009, 08:16 PM | #21 |
Live 2 Ride Forced 2 Work
Name: Chris
Location: Guam
Join Date: Mar 2009 Motorcycle(s): 2008 RED 250r Posts: 386
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Before I didn't have any hesitation at start up either but riding in 1st was sometimes a bit jerky. I shimmed the needles and pulled the snorkel and it almost doubles the performance of the bike. There is a huge difference in low end power and up past 9/10 RPM it is a whole new machine. I haven't even got my aftermarket exhaust yet but with the power increase and the deeper engine roar it almost feels like I got one already. I can't say enough good things about this simple mod and props to Kkim for helping me through it!
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May 19th, 2009, 04:20 PM | #22 |
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Name: Travis
Location: Warwick, RI
Join Date: Apr 2009 Motorcycle(s): 2009 Ninja 250R Posts: A lot.
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Kim:
The bike is currently stock and only time I have ever experienced any bogging is if the bike is extremely cold and I am carring a pasanger (then we weigh together about 300 pounds). When I am alone I have no problem. I open the choke to start but after about 10-20 seconds I can close it and it idles just about 1400rpm. I currently get about 53 MPG mostly highway. Should I do this mod or should I leave well enough alone? Also I was thinking of removing the snorkel. If I do then I think I will definitely need to shim it, but until I decide to remove it what should I do?
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May 19th, 2009, 04:27 PM | #23 |
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Travis,
If you are happy with how the bike is running, leave it alone. The shimming idea came about for people that were having real problems with stalling and a hard time moving off from a stop even after the bike was fully warmed up. Sounds like you may have been one of the lucky few that got a bike that wasn't lean from the factory. Once you do remove the snorkel, though, you will most likely need to shim. |
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May 22nd, 2009, 09:10 AM | #24 |
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Name: Shish
Location: SGV, CA
Join Date: Apr 2009 Motorcycle(s): Ninja 250 Posts: 35
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I was searching for threads about "throttle lag" and found this one which i think might describe my situation.
My bike only has about 230mi and this just started to happen recently for some reason. I noticed when i first took it out for a ride, pulling out from a stop and in first gear i would put the clutch into the usual friction zone while revving up to about 2000rpm. What was odd was that it didn't rev! I had to open the throttle a little bit more but by then it would just jump up out of nowhere. I now have the bike on stands and the fairings off and am trying to fix this problem. I thought maybe it was throttle adjustments, but it seems fine. Bike is a CA model, 08, 230mi, idles at 1300. When i start the bike it usually hesitates a bit, in cali warm weather. It will then idle after a bit of working but sounds like it's struggling. So i would put on the choke for a few seconds then turn it back off and get on my way. I try to start it up without the choke but it would be easier if it were on. Anywho, when i slowly rev the bike it it seems fine. But if i were to open the throttle a little quicker it would lag, count 2 seconds, then it would jump up high. Sometimes it would stall. Does shimming sound like what i need? Or could it be something else? Thanks! |
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May 22nd, 2009, 09:19 AM | #25 |
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Name: Rick
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KKim,
If you mod your bike with a full exaust and filter pods will shimming alone be sufucient or do you still have to get a jet kit? |
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May 22nd, 2009, 09:34 AM | #26 |
Giggity Giggity
Name: Ryam
Location: San Diego
Join Date: Feb 2009 Motorcycle(s): 08 ninja 250R aka Hiryu Posts: 481
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I am assuming that people having the hesitation are rolling on the throttle not just cracking it on?
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Facebook DY Fender chop, Danmoto CB slip-on w/baffle, Airbox removed, Kleen-air removed, shimmed needles, Mikuni #117.5 Main jets, K&N RU-1822 air filter pods |
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May 22nd, 2009, 09:41 AM | #27 | |
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Name: Nick
Location: Occoquan, VA
Join Date: Nov 2008 Motorcycle(s): '09 Ninja 250R Posts: 518
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Quote:
Good question. In addition, if shimming is sufficient, what is the advantage of a jet kit? |
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May 22nd, 2009, 09:46 AM | #28 |
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Name: Nick
Location: Occoquan, VA
Join Date: Nov 2008 Motorcycle(s): '09 Ninja 250R Posts: 518
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May 22nd, 2009, 09:49 AM | #29 |
Giggity Giggity
Name: Ryam
Location: San Diego
Join Date: Feb 2009 Motorcycle(s): 08 ninja 250R aka Hiryu Posts: 481
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K just making sure nobody is confused in the difference on rolling on the throttle smoothly and quickly than snapping it on. I am sure doing the latter no amount of mods will not cause hesitation.
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Facebook DY Fender chop, Danmoto CB slip-on w/baffle, Airbox removed, Kleen-air removed, shimmed needles, Mikuni #117.5 Main jets, K&N RU-1822 air filter pods |
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May 22nd, 2009, 11:47 PM | #30 |
ninjette.org member
Name: Brad
Location: Oahu, Hawaii
Join Date: May 2009 Motorcycle(s): none Posts: 30
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So, this will be my first "tech" post. Please be gentle.
Will shimming the carb needles be sufficient enough to allow me to run an aftermarket slip on exhaust. All of the research I have done almost everyone has said that if you are gonna run an aftermarket slip on, you have to rejet to avoid long term damage to the engine by running it to lean with the stock jets. How do you guys feel about this? Does it matter? |
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May 22nd, 2009, 11:50 PM | #31 |
Join Date: Nov 2008 Posts: Too much.
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This is an excellent, easy way to richen up the mixture in the low-midrange to bring the bike alive. I would think with a slip on and removing the snorkel, you would be very happy with the results.
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May 22nd, 2009, 11:59 PM | #32 | |
Join Date: Nov 2008 Posts: Too much.
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Quote:
Until the bike is fully warmed up (about 10-15minutes of riding w/ stock jetting), the throttle will have that noticeable lag if you gas it quickly. After the bike is warm, it should improve, but don't expect instant throttle response, even when warm, due to the CV carbs the bike comes with. It's just a characteristic of the carbs' design. Whether you need to shim is another question, but shimming will not fix what you have described here. |
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May 23rd, 2009, 12:03 AM | #33 | |
Join Date: Nov 2008 Posts: Too much.
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Quote:
You could get excellent results by experimenting with shimming the needles, changing the mains and readjusting the mixture screws if you went to a separate pod air filter setup/full exhaust. |
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May 23rd, 2009, 12:07 AM | #34 | |
Join Date: Nov 2008 Posts: Too much.
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Quote:
They also give you a selection of mains so you can dial in the full throttle power to your particular location. Some jet kits even provide you new pilot jets to richen up the idle mixture for a smoother, more powerful low end/off idle response. |
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May 23rd, 2009, 12:09 AM | #35 | |
ninjette.org member
Name: Brad
Location: Oahu, Hawaii
Join Date: May 2009 Motorcycle(s): none Posts: 30
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Quote:
I think my biggest concern is long term reliability. How will this effect the bike down the road after XXXX miles? |
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May 23rd, 2009, 12:12 AM | #36 |
Join Date: Nov 2008 Posts: Too much.
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Actually, if done correctly, the bike will run cooler than the stock jetting after shimming, so I would say longevity would go up.
The extra wear and tear you'll provide from wringing the bike out because it's so much more fun after you shim is an entirely different matter. How long do you plan to keep the bike? |
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May 26th, 2009, 01:31 PM | #37 |
ninjette.org member
Name: Francisco
Location: Bradenton
Join Date: May 2009 Motorcycle(s): 09 Ninja 250R Posts: 18
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I wish i would have read this thread before doing the mod. My bike is completely stock, and i put 2 washers on both needles. Put the gas tank back on tested it out and it kept dieing when i gave it too much throttle. So this thread would have saved me a lot of time.
At least going back and having to take the needle out to remove the washer went 5x faster (and thats no exaggeration) because i now knew what to do and had some technique to getting to those tough screws. |
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May 26th, 2009, 02:43 PM | #38 |
Join Date: Nov 2008 Posts: Too much.
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what size washers did you use?
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May 26th, 2009, 03:45 PM | #39 |
ninjette.org member
Name: Francisco
Location: Bradenton
Join Date: May 2009 Motorcycle(s): 09 Ninja 250R Posts: 18
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Sent you a PM
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June 5th, 2009, 10:03 AM | #40 |
ninjette.org member
Name: Tom
Location: Kentucky
Join Date: Jun 2009 Motorcycle(s): None yet Posts: 13
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First post here, and a question:
This mod looks like it only affects the mixture at close-to-idle. Do I assume that MPG will not appreciably be affected? |
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