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Discussion Starter · #1 ·
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.

While there is a great DIY on how to do this to your bike, 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 characterstics.


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 setting 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! J) 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.

Look on this page of the DIYs for a DIY on getting the bodywork off, if you desire to take everything off instead of pushing the fairings outward as in the DIY.

http://www.kawiforums.com/showthread.php?t=108573



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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when you have some time, would you mind sharing your experince with shimming? Your bike was one of the ... how shall I say it... unique ones? :Damn:

Yeah. I'll post something tomorrow. I'm gonna go ride a little right now.
 

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enjoy yourself, man... be careful... isn't it dark?
You know this came up last night when Mysta, you and myself were all online till the wee hours of the night. What IS the time difference there in Hawaii anywho? Like what time is it now?
 

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Discussion Starter · #9 ·
You know this came up last night when Mysta, you and myself were all online till the wee hours of the night. What IS the time difference there in Hawaii anywho? Like what time is it now?
3hrs behind west coast... it's 6:30 pm
 

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enjoy yourself, man... be careful... isn't it dark?
Yeah it is. Just having a poopy week and need to get out and clear my head a little, ya know? :)

I was gonna watch a DVD on my laptop but the drive stopped working and that was the last straw and I gotta get out of the house before I shoot someone.
 

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Discussion Starter · #11 ·
Yeah it is. Just having a poopy week and need to get out and clear my head a little, ya know? :)

I was gonna watch a DVD on my laptop but the drive stopped working and that was the last straw and I gotta get out of the house before I shoot someone.
lol... have fun... but again, be careful... must be my old eyes, but I don't see so good at night, so I ride really cautious when it's dark.
 

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Discussion Starter · #13 ·
ok guys - Kelly took the time to make this thread - WTG KELLY!!!!!
thanks, hokie... np, this thread is a general sounding board for anyone that has questions or experiences to share about shimming to post up... the more they PW on it, the better the chances of it staying out in the open for all to see and post their questions. :)

btw, is what I posted sound about right?
 

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I have been debating on shimming since I first read about it. I live in the SF bay area and never need any choke to start, once warm there is no studdeering off the line or hesitation. After reading this I don't think shimming is for me, unless I put on my HR1.
Agree? Or would there be any gain with a washer or two?

I think this thread needs a little clarification on rejettting vs shimming and why someone would do one and not the other, or both.

Kkm, good right up. I think it will help many people.

Also, what is the offset wrench that I have read about? Part number? Link? From what has been posted this tool has helped greatly!
 

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I have been debating on shimming since I first read about it. I live in the SF bay area and never need any choke to start, once warm there is no studdeering off the line or hesitation. After reading this I don't think shimming is for me, unless I put on my HR1.
Agree? Or would there be any gain with a washer or two?

I think this thread needs a little clarification on rejettting vs shimming and why someone would do one and not the other, or both.

Kkm, good right up. I think it will help many people.

Also, what is the offset wrench that I have read about? Part number? Link? From what has been posted this tool has helped greatly!
 

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when you have some time, would you mind sharing your experince with shimming? Your bike was one of the ... how shall I say it... unique ones? :Damn:


OK, well my story was a strange one compared to others.

I originally shimmed the bike with 2 washers when it was stock except removed snorkel. That was way too rich. Could barely get the thing to rev past 3-4k. Stalled a bunch of times on its own. Took out 1 washer and it was 'better' but still much worse compared to stock. I was able to get it into higher RPM but it felt weak and down on power.

I changed to an Area P quiet core and thought it would be necessary for some shimming to get it to run right. So I shimmed with 2 washers again at the same time as the exhaust install. To my surprise, the bike was acting the same as it did stock when I added 2 washers. :dunno: Tried 1 washer again and same results. A little better but still rich and running very poorly. Terrible response, studdering, etc.

I ended up putting the needles back to stock and as of now this is where I left it. AreaP, snorkel out, no shimming and the bike runs great.


I never experienced the issues when the bike was stock that many did. Mine will start up with no choke, needs no choke to hold idle when cold, and will warm up rather fast. It's rideable after only a minute or two. Basically by the time I finish putting my gear on, I can hop on the bike and ride away.
 

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Discussion Starter · #18 ·
Sounds OK. Should have touched on the "idle mixture screws" a bit :)
I would, except shimming the needles actually takes care of having to redo the mixture screws in a crude way. End result is that raising the needles "fixes" the lean mixture problem by allowing more fuel at idle with the raised taper in the needles. For someone that doesn't want to pull the carbs to undo the plugs to get to the mixture screws, this is a quick easy way (in comparison to pulling the carbs) to the lean idle circuit many bikes are plagued with.
 

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Discussion Starter · #19 · (Edited)
I have been debating on shimming since I first read about it. I live in the SF bay area and never need any choke to start, once warm there is no studdeering off the line or hesitation. After reading this I don't think shimming is for me, unless I put on my HR1.
Agree? Or would there be any gain with a washer or two?

I think this thread needs a little clarification on rejettting vs shimming and why someone would do one and not the other, or both.

Kkm, good right up. I think it will help many people.

Also, what is the offset wrench that I have read about? Part number? Link? From what has been posted this tool has helped greatly!
Sounds like your bike might be one of the "good" ones (read kurosaki's post below). Put the HR1 on and see if the bike feels like it loses power or surges at light throttle openings when cruising at highway speeds.If so, you might want to shim the needles.

Shimming is like a crude rejet which , in my opinion, will get you 75% of what you might gain with a jet kit. The jet kit allows you finer tuning of the carbs for people that are more fussy about their bikes. My suggestion is to shim first and see if the results are good enough for you. If you are happy with the results, leave it alone and ride it.

The offset Milwaukee screwdriver is only needed when you want to get to the mixture screws, which has nothing to do with just shimming the needles.

http://www.kawiforums.com/showthread.php?t=114859
 

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Discussion Starter · #20 ·
OK, well my story was a strange one compared to others.

I originally shimmed the bike with 2 washers when it was stock except removed snorkel. That was way too rich. Could barely get the thing to rev past 3-4k. Stalled a bunch of times on its own. Took out 1 washer and it was 'better' but still much worse compared to stock. I was able to get it into higher RPM but it felt weak and down on power.

I changed to an Area P quiet core and thought it would be necessary for some shimming to get it to run right. So I shimmed with 2 washers again at the same time as the exhaust install. To my surprise, the bike was acting the same as it did stock when I added 2 washers. :dunno: Tried 1 washer again and same results. A little better but still rich and running very poorly. Terrible response, studdering, etc.

I ended up putting the needles back to stock and as of now this is where I left it. AreaP, snorkel out, no shimming and the bike runs great.


I never experienced the issues when the bike was stock that many did. Mine will start up with no choke, needs no choke to hold idle when cold, and will warm up rather fast. It's rideable after only a minute or two. Basically by the time I finish putting my gear on, I can hop on the bike and ride away.
Thanks for sharing... I'm sure people will read your post in the future and get a lot out of it.

mahalo
:)
 
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