DIY Shimming the carb needles.

[jenndiggity]

Thanks Richie! What I ultimately figured out is that although some threads say there is an overflow for the gas tank, there isn't. You have the vaccuum and fuel lines in the petcock but even though there is a nipple on the fuel sending unit, nothing needs to be attached. I ended up connecting a hose to that middle nipple between the tops of the carbs and left the other end to point down out of the bike as an overflow.
I also found that the #3 washer was too big- I'm assuming after using one #3 and seeing black smoke spew from my can. So I made a shim (the copper one on the needle depicted) that would allow the needle to seat cleanly inside that plastic thingy inside the spring. Problem solved!

[jgo564]

Just shimmed adding 2. Must say, 3mm washers aren't the easiest to find at your local hardware store. First test drive seemed like it has made a difference, but we'll see tomorrow morning when the bike has been sitting still and cold overnight.

Couldn't have done it without this guide!

[3sgte]

is it bad if you shim just one of the needles and ride it? I accidently stripped one of the screws on the second carb (the last one too ) I have to use my bike to get to uni and it'll be a few days before I will be able to take the carbs off to replace the screw. Would there be any damage if I ride it like this?

[geeker]

Originally Posted by 3sgte

is it bad if you shim just one of the needles and ride it? I accidently stripped one of the screws on the second carb (the last one too ) I have to use my bike to get to uni and it'll be a few days before I will be able to take the carbs off to replace the screw. Would there be any damage if I ride it like this?

I wouldn't ride that way. One cylinder will get more fuel than the other. At the very least, it won't run right. At the worst, I assume you could cause some ignition or make the throttle behave incorrectly.

[3sgte]

Originally Posted by geeker

I wouldn't ride that way. One cylinder will get more fuel than the other. At the very least, it won't run right. At the worst, I assume you could cause some ignition or make the throttle behave incorrectly.

Oh ok. Guess i'll have to take the washers out till I have time to fix it. Thanks a lot for that Richie.

[Jiggles]

I have stripped a couple screws and I can usually get them out using some needle nose pliers. Squeeze hard and turn!

[3sgte]

Originally Posted by Jiggles

I have stripped a couple screws and I can usually get them out using some needle nose pliers. Squeeze hard and turn!

I have never stripped a screw so I wouldn't have a clue of how to get it out I'll definitely try your method out

[Jiggles]

If its not obvious, you'll want to have the pliers perpendicular to the screw

[3sgte]

yeah I tried the pliers but I couldn't get the right angle so I ended up using a dremel and making a line in the middle of the screw so I could use a flat head to get it out.

[r6boater]

Although we weren't able to find the correct size of washer, my 12 year old made some shims out of an old license plate. He drilled a hole and then using shears, cut a "donut" the same size as the needle head. Used two per carb and it made a huge difference! Runs much better now.

[1ER6F]

Originally Posted by choneofakind

The jetting database is a good idea of where to expect your jetting setup to end up, but it's just a starting place. Test-riding is still mandatory for jetting.

Thaaaaank you! Been looking for a thread just like this!
Just did the snorkel removal with needles shimmed with two washers for now.
What can I say... : )
Next stop full exhaust, k&n air filter, and jet kit!

[choneofakind]

[ricomtzjr]

I will be doing this mod soon...

I bought my '12 250 in October with 1 mile on it. I currently have 1800 miles on it now, still stock setup.

What I have noticed as the temps have slowly been getting lower is a slightly longer warm-up, some sputtering while trying to take off, and great top end while the engine isn't fully warmed up. Once at normal operating temp, these issues kind of reverse. Take off isnt like a turbo spooling up and the top end seems to degrade ever so slightly. Since I'm still learning the bike, I will start with the shimming to get a taste and eventually a re-jet.

Here in El Paso, the elevation is about 3800 feet. Temps are 60-70s for the highs and 30-40s for the lows. It is very dry and dusty here. I'll keep posting here and give my results. I noticed there aren't any El Paso 250 riders on this forum, or any other 250 forum. I have seen a handful around, but no contact. Three of them are actually on post here at FT Bliss too.

So since I haven't seen any info on tuning in my location, I will jump in on it this weekend...

Stay tuned...

[LNasty]

So is there clips on the needles? If so, I put the washers above or below the clips? Our do I take the clips completely off? I have a 2012 250. Put a Leo Vince slip on on. Going to remove snorkel. will shimming hurt the bike in any way?

[geeker]

There are no clips on stock needles. Jet kits, like Factory Pro or Dyno Jet, come with new needles that are adjustable with clips. Stock needles don't have this feature, so we emulate it by using washers.

[ricomtzjr]

Currently 600 miles on my bike since shimming (x2) the carbs and pulling the snorkel. At first, it didn't seem to run well, but has run better from day to on until now. This setup works well at 3800 feet up to 5000 feet, as well as down here at lower levels in San Antonio and near Dallas. More power accross the power band and still 50+ mpg on the highway. Not much city driving.

[LNasty]

Just got done shimming carb and what a difference. Only took an hour to do and best mod I could have done yet. By the way #6S brass washers from Depot work perfect. Thank you to all that gave me advise on doing this mod.

[rocka81]

got through shimming the needles on my bike today, i had some 4mm washers already that i was going to use (Until i read through here) but headed down to jaycar and scored a pack of 3mm washers for a whopping $3. I used 2 washers under each needle and perfect results for my bikes setup. My bike only has the snorkel removed with a mussari slip on.
Started to strip the front left screw on the left carb, then stopped and put the needle nose vice grips on as well as the screwdriver to crack it, and presto.

Absolutely loving all the info on this site

[NinjaPunk]

Just shimmed my needles (2 of the radio shack washers each) to go along with the snorkle delete and Leo Vince slip on....huge difference in performance.

In order of what I did in the last 4 days:

1. Installed Leo Vince slip on : Noticable performance gain...weight savings alone was nice. Got a bit more top end out of it.

2. Removed snorkle : That's when the lean-ness was noticleable...took much longer to warm up...had some flat spots...top end was suffering.

3. Shimmed 2 washers each needle : This maximized the two airflow mods...this morning it started up with no choke at all...pulls *much* stronger on the low end...pulls solid all the way to redline. I've not tested he top end yet but will probably tonight, but will no doubt run all the way to redline in 6th with no problem.

Next mod will be adding a tooth to the front sproket...the added power will make that a great mod for performance and highway mileage.

These instructions were great!...make sure to pick up either an offset screwdriver or in my case I had a long enough screw driver to easily get to the carb cap screws. Also have a long enough set of needle nose pliers to get the needles out.

[menikmati]

Originally Posted by NinjaPunk

Also have a long enough set of needle nose pliers to get the needles out.

If you take the carb tops off, you can remove both the vacuum slides and needles by using your pinky. Not as professional as using needle nose pliers, but I wouldn't want anything sharp near the vacuum slides to prevent damage as they're fairly expensive.

[conrya5]

Originally Posted by NinjaPunk

Just shimmed my needles (2 of the radio shack washers each) to go along with the snorkle delete and Leo Vince slip on....huge difference in performance.

In order of what I did in the last 4 days:

1. Installed Leo Vince slip on : Noticable performance gain...weight savings alone was nice. Got a bit more top end out of it.

2. Removed snorkle : That's when the lean-ness was noticleable...took much longer to warm up...had some flat spots...top end was suffering.

3. Shimmed 2 washers each needle : This maximized the two airflow mods...this morning it started up with no choke at all...pulls *much* stronger on the low end...pulls solid all the way to redline. I've not tested he top end yet but will probably tonight, but will no doubt run all the way to redline in 6th with no problem.

Next mod will be adding a tooth to the front sproket...the added power will make that a great mod for performance and highway mileage.

These instructions were great!...make sure to pick up either an offset screwdriver or in my case I had a long enough screw driver to easily get to the carb cap screws. Also have a long enough set of needle nose pliers to get the needles out.

I am on this same path! Just shimmed my needles last night. I'm glad to hear another good report on these mods because my bike is having the same symptoms as yours did.

[conrya5]

Originally Posted by rocka81

got through shimming the needles on my bike today, i had some 4mm washers already that i was going to use (Until i read through here) but headed down to jaycar and scored a pack of 3mm washers for a whopping $3. I used 2 washers under each needle and perfect results for my bikes setup. My bike only has the snorkel removed with a mussari slip on.
Started to strip the front left screw on the left carb, then stopped and put the needle nose vice grips on as well as the screwdriver to crack it, and presto.

Absolutely loving all the info on this site

I was able to find #4 washers at a local hobby store for $ 0.89.

+1 on the information this site has to offer

[broken neck]

Well,

Finally, I've took the time to shim the needles (one washer par needle) and drilled the carburetors slides. I could only start the engine next to my friend's garage (still some snow over here and lots of little gravel on the streets and corners.

My bike is engine is completely stock with the stock exhaust. Will I be alright with those things done? Or messing with the needles and adding holes lead to other things to do?

And by the way, a huge thanks for all of you who took time to put up those DIY. Very handy and it helps a lot!

Thanks,

[choneofakind]

You'll be fine

[broken neck]

Well,

The bike is not running as I expected it to do. Under 5 000 rpm it's hesitating as hell and I have to give it a lot more gas to be able to star from stand still. Over 5 000 rpm it looks alright. After a while, if I have to stop at a red light or at a stop sign, the engine would stall. To keep it running, I'll have to turn the gas at "WOT" for more than 2 minutes before I can get going again. And there is this black or dark smoke coming out the exhaust.

I think the engine might be running too rich.

For an "easy fix", I removed the snorkel, and went for another try. Same problem but under 4 000 rpm this time, same bogging down, same stalling after riding it and coming to a complete stop. Same smoke.

So, is the engine still too rich?

I've put #3 washers, should I go with 3mm washers? I haven't mess with anything else, except drilling the slides and removing the snorkel today.

Thanks for your input or your help.

I thought I was making my throttle "smoother" for stop and go traffic, but it's just the opposite that happened.

And last question, should I change my spark plugs? I rode about 60 miles today with that problem. I thought at first I was dealing with gas that stayed in the tank for a little less than four months and it was my first ride of the season.

Thanks again,

[choneofakind]

Have you changed anything else or just shimming and snorkel removal?

What size are your washers? The should be about 3mm ID, 6mm OD, and 0.5mm thick.

[broken neck]

I've just raised the needle, drilled the carburetor slide and removed the snorkel (in an lasy way to fix the problem, since I was at my mother in law house with no tools but my leatherman).

I've just measured the washer I used in the carburetors, they're 1.54 mm thick, so that must be my huge problem. I've read that using #3 washer was ok, but I guess those I got are way to thick, I've found some in the bin that are 0.8 mm thick.

I'll order the 3mm washer, then I'll have the correct one.

Thanks for your input.

I'll report when I'll have swap them.

Since I'll have to order them, is there a better material to use?

[choneofakind]

No, I would stick with metal washers. Vinyl ones might be affected by gas or ethanol, idk. Metal is a good option.

Yes, the thickness is your problem. With just a snorkel pulled, you'll likely need either 0.5mm or 1mm worth of shimming. The carbs are sensitive to some very small adjustments.

[broken neck]

Just an update...

Finally found some 0.5mm thick, but the outside diameter was 8.0mm, bought them, I was to impatient to wait Monday for the 6.0mm.

Pulled everything apart once again. Tried the new washer, they don't get stuck in the "white plastic" aka seat spring valve. Reassembled everything.

Geared up myself, started the Ninjette, went for a ride... Problem solved...

And as claimed by other, I found the bike was easier to control in traffic or in slow speed...

So, you could use the 8.0mm outside diameter, but If you can have those 6.0mm, I would put those in...

Thanks everyone and choneofakind...

A guy who is too happy to be able to ride after this too long winter...

[DaBlue1]

Originally Posted by choneofakind

No, I would stick with metal washers. Vinyl ones might be affected by gas or ethanol, idk. Metal is a good option.

Yes, the thickness is your problem. With just a snorkel pulled, you'll likely need either 0.5mm or 1mm worth of shimming. The carbs are sensitive to some very small adjustments.

Oh choneofakind,

I is disappointed, you know there is no gas in the top of the diaphragm. The correct size vinyl or plastic washers will work fine. (ask me how I know) Also you can shim up to 1.62 mm and be ok. Depending on the size (thickness of your shims) will determine how many you use. (For example 1 Factory Pro washer is about 0.54mm thick. I have two 3 mm washers that mic @ 1.53 mm.) Some have used as many as 3 (0.54 mm) washers successfully.

[choneofakind]

Originally Posted by DaBlue1

I is disappointed, you know there is no gas in the top of the diaphragm. The correct size vinyl or plastic washers will work fine.

There's still going to be some amount of gas. There's a hole in the bottom of the slide that's open to the inside of the carbs. There's still a chance for gas there. Maybe a very tiny amount, but it's still a possibility. Notice how the slides smell like gas when you pull them out?

Idk, I'm still not comfortable using vinyl washers in something related to gasoline. Maybe I'm just paranoid.

[JosueDG]

Just read through and looking forward to adding this DIY to my weekend list of things to do!

[broken neck]

Originally Posted by choneofakind

There's still going to be some amount of gas. There's a hole in the bottom of the slide that's open to the inside of the carbs. There's still a chance for gas there. Maybe a very tiny amount, but it's still a possibility. Notice how the slides smell like gas when you pull them out?

Idk, I'm still not comfortable using vinyl washers in something related to gasoline. Maybe I'm just paranoid.

Not just a chance, you can find gas up there. I had some in my left diaphragm when I changed my washer. I was a bit puzzled, because the right one was dry.

[garix]

I just did this mod and guess how many times I had to open up my carbs?

5 times due to my ignorance and impatience. Read ahead to learn from my downfalls and it should save you some time/troubleshoot if you run into same problems I did.

First of all, GET THIS TOOL!!!
http://www.harborfreight.com/8-piece...ver-92630.html

First time I did it, none of my screwdrivers or wrenches would fit into the back screws so I ghetto rigged a phillips to a socket to another one to a metal spoon handle (Yes you read that right). It worked fine but was a pain in the ass to find what out what fit and what didn't fit due to the frame being in the way. I then added two #4 washers because I have a two bros exhaust, fired her up and the engine would die instantly.

Second time I took off the carb caps was to revert back to stock. Nope, same problem.

Now I know I definitely hooked up something wrong so I looked at the carb diagram pics and found out I hooked up one of the hoses into the carb vent hose, silly me...

Third time's the charm right? So I rehooked the hoses correctly and added two washers again, fired her up and she was great! I took her for a ride down the street and BAM, nothing above 6k rpm. I was WOT and the rpm would stay at 6k so something was definitely wrong.

I thought my bike was running too rich so I reverted back to stock ONCE AGAIN. Did that fix it? NOPE...

I googled around and found out that this occurs when there is no vacuum (air leak) in one of the carbs. I started to worry thinking that I had ripped one of the rubber diaphragms then I realized I screwed on the choke cable holder in between the carb plate and the carb. So finally I put everything back together and now she runs PERFECTLY with two washers with a two bros exhaust and the snorkel delete!!

I was very impatient and rushed so I wasn't paying attention on where everything went and didn't have the right tools.

tl:dr: Get that right angle screwdriver before attempting this, have the diagrams/pictures out of what hose goes where and what screws go where as many people have connected them wrong. It'll save you hours of troubleshooting!

[greenswoave]

Did this job over the weekend. Ratchet angle screwdriver is a must. I used a drywall bit to get the JIS screws out with no problem and replaced the screws with stainless steel phillips. Had to take the heads off twice because the first time I pinched the rubber (no tears thank god). I used two 3mm washers from Home Depot on each needle. I noticed a 5 mpg drop in fuel economy (53 to 48), but the throttle response, lack of bogging down at low RPMs, and majorly reduced time to warm from cold made it totally worth it. Highly recommend.

[Olie]

OK, I'm new to the carb set-up (been spoiled with EFI), I have a stock bike and I want to add the K&N filter and pull the snorkel. With what I've read, a .5mm to 1mm shim set up should do what I'm looking for? Here in Hawaii the morning temps are around 60 but choke is still needed for start up but warms up fairly quickly, like 5-7 minutes. With the added air flow from the K&N and snorkel removal, is the thickness of .5mm going to be enough or should I just go with 1mm?

If this has been answered elsewhere I apologize, I've been searching like crazy and the thickness issue seems to be one that is harder to find.

Thanks for your help, these forums have been AWESOME for info!

[DaBlue1]

Originally Posted by Olie

.... With the added air flow from the K&N and snorkel removal, is the thickness of .5mm going to be enough or should I just go with 1mm?

You will have to experiment with this. Every bike is different. IMHO i would go with 1mm+, .5 mm just is not going to do much if anything.

[Olie]

Originally Posted by DaBlue1

You will have to experiment with this. Every bike is different. IMHO i would go with 1mm+, .5 mm just is not going to do much if anything.

Thanks for the input. I took her out today to try and open it up. To me, she has good power throughout the RPMs but seems to pull hard from 7,000 and up. Unfortunately it was raining and a bit windy so I couldn't hear much and didn't go over 70-75 but there was definitely some room still with the throttle. So, I'm hoping with the extra air flow and then 1mm shims will give some of that pull in the low/mid range too. I will update after I try it out. Hoping for tomorrow!!

On another note, the bike only had 1100 miles on it when I bought it but it is obvious the first owner did some work on her, there's a battery tender connection I found under the left side panels. So, I don't know what else has been done to include any carb work.

[chillbr0412]

Would these work?

http://www.lowes.com/pd_136250-37672...3012237&rpp=32