Kawasaki KLR 650 Mikuni TM42-6 Flatslide Pumper Carb Kit

(7 customer reviews)

$710.00 AUD$735.00 AUD

Select you Carb with either a short Knob Choke or 200mm Cable and Bracket

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The performance change you will experience with this carb fitted is nothing short of amazing. With a stock motor running road gearing and an exhaust system fitted, a quick blip of the throttle when riding along the road in second and the front wheel’s up, crack it hard and you’ll loose traction. No hesitations or flat spots just a Kawasaki KLX KLR 650 on steroids.

The 42 is by far your best performance option and worth every bit of messing around with fitment. To get the power improvement required for 2nd gear wheel stands you must have a performance muffler fitted and be prepared to drastically open the air box to allow it to breath. If wanting to use a POD filter please contact us for recommendations and supply with a different inlet sleeve option.

The Mikuni TM42-6 HSR flows 17CFM more than our TM40-6 and incorporates many upgraded features such as a roller-bearing slide. All this means going even faster has never been so easy, say goodbye to stock carb sluggish throttle response, hesitations and flat spots.  These Mikuni carburetors are correctly sized and easily fitted to your Kawasaki KLR 650 stock air box when using the  silver anodized air-box adapter. This adapter  is fitted prior to delivery when purchasing complete kits. There is also an anodized aluminium spacer with o-ring seal provided for spacing back the KLR650 OEM rubber carb mounting flange. For this Mikuni carburetor to operate correctly the motorcycles air box must be opened up as per the picture to allow way more air flow in. The kit also comes with throttle cables and a 1/4 turn quick action throttle. After extensive testing the jets fitted should nail your tune straight out of the box. Pre-delivery we perform some other carb mod’s including most importantly the fitting of a size 30 pump nozzle which is unique to Mikunioz. Climate, altitude and fuel density from different octane fuels all have varying effects on final fine tuning as does cam, exhaust and cylinder head porting etc. For this reason we have installed what we have found to be a range of jets to allow you to tune to most variables. Though the TM42-6 will accept some OEM CV carb choke cables, the KLR choke will not work on this carb. Therefore this kit is sold with two options found in the purchase drop list, being with either a knob choke assembly, which is accessible on KLR’s not using factory crash bars or otherwise with a 200mm choke cable and universal bracket for access if you have the crash bars fitted. You will though find that you never usually require the use of the choke.

On the Kawasaki KLR650’s with the  single frame bar above the carb, the supplied 10mm wide, port matched rubber mounting flange spacer needs fitting to move the carb back for starter motor clearance. You may then need to on some bikes remove some material from the top motor mount frame bracket and the rear weld attaching it to the tube. The rubber snorkel coming from the air-box needs shortening to compensated for the spacer and when attached will then pull the carb back down. To rectify this, use a zip tie looped over the frame above to lift the carb back upward. The rubber soon re-shapes and de-stresses itself after a while with engine heat. The jetting we supply fitted is generally perfect and unfortunately with this bike you have to remove the carb for any jet changes if doing a main jet tune check or any other changes but as we’ve stated earlier the inconvenience of this is minuscule compared the weapon it creates.

Fine tuning is generally related to exhaust system with the KLR650 where the supplied setup is in most cases perfect but if you don’t get that instant “WOW I’ve got myself a crazy wheel standing machine” feeling,  it will usually only usually relate to pilot jet size and or needle clip position setting. If at all confused or in need of guidance we offer our customers, business hours phone support for any carb we sell. The TM42 for big Jap singles are now our most popular selling kits worldwide and our knowledge base for tuning to different engine configurations of all brands is extensive.

Please advise at purchase or by email prior, your bikes model, year, exhaust and other engine setup details so we can supply the carb best pre-jetted to suit. A spare pilot and two spare mains are supplied in case they are required. International customers please provide your local fuel octane rating so we can also make compensations for this if necessary.

You will instantly experience way better throttle response, improved smooth acceleration, increased horsepower and torque.  Plus the bonus of better fuel economy. For this bike the custom reviews tell the story and will definitely impress you especially when watching Glens YouTube clip. To fully appreciate the potential this carburetor has you must fully read and follow the provided fitment and tuning sheets.

For Bikes fitted with big bore kits looking to squeeze out every available bit of power:

When fitting Big Bore kits there is normally no requirement to purchase extra jets, just again check the tune settings, where only the fitting of a cam would have any drastic change on jetting setup. When trying to squeeze every little bit out of your engine it will become time to bin the OEM filter system all together. This requires cutting out the front of the air box to accommodate a large POD filter being either a 150mm long highest flowing Uni-Filter with sock or similar size cloth paper type POD. When wanting to go this way, please advise and we can either fit a 63mm OD extended sleeve for pushing the filter back further into the air box or provide this loose as a future option for yourself, where you’ll connect a POD directly to the carbs 65mm inlet spigot. The OEM 58mm inlet diameter and air box boot does choke the air supply down a bit with the bigger capacity engines.

To clarify some commonly asked questions about this carb in regards to a comparision with the 40mm: 

In the late 80’s Mikuni American released the HS40 (TM40-6) as an amazing new carburetor for the Harley Davidson market, literally knocking all its competitors out of the park. We were at the San Jose Custom Chrome Show when it was released and become part of that buzz as Australian Mikuni distributor. This slide type fuel metering device basically made the competitors butterfly type carbs seem like lawn sprinklers.
With the huge increase in Harley Davidson sales this became a very lucrative market. Recognizing the potential of this market and being aware of the efforts of competitors to try and grab back their share of it made Mikuni realize the necessity of replacing the 40 with a carburetor to be the be all and end all of all carburettors. The target was to deliver unrivaled peak performance combined with smoother throttle operation and lighter throttle pull by replacing the metal on metal slide action with a slide running on roller bearings. Also a larger fuel bowl capacity was provided but most of all, superior venturi design and fuel atomization resulting in more precise mixture ratios to not only increased horsepower and torque but also to enable the fitment of a larger carb to smaller capacity engines without losing valuable bottom end power, where in fact instead gaining more. In 1994 the HSR42 was born and just like you will if you fit one to your bike, all we could say was WOW. Instant throttle response delivering 25% more horsepower and torque over the stock CV carb before even putting on a real high flow air-cleaner. As the badge says 20 years later” Still the best performance carburetor on the planet”.
Unfortunately, the TM42 only had limited sales in the Japanese single market due to it only appealing to the custom fitter as there had never been a cable set or air-box adapter available off the shelf. With the slowing of the Harley market due to fuel injection on new bikes, here in Australia, Mikunioz realized the opportunity to offer Mikuni’s best Carburetor to the big Jap single market and in late 2015 we released a range of ready to roar direct fit up kits with correct jetting and a few trick mods to make them work better than anything before on big Jap Thumpers.

The fuel consumption is way less but when comparing with the stock carbs, it all depends on how having a lot more power and torque effects your riding habits. If you can manage to back off and just have your bike perform at its present level you’ll be surprised by the fuel economy, but of course when the same amount of throttle twist becomes front wheel lifting, breaking traction action, well it’s hard to not want to go and play. If you have more horses in the paddock and you want them all to perform, you have to feed them more hay! 

You will enjoy this new carb but do be sure to hold on tight on your first test ride as she may try to spit you off if you nail it to hard.

All international buyers are responsible for the payment of their domestic customs duties and taxes charged on imported goods. The duty free threshold and duty/taxes payable rates differ from one country to another and we strongly advise you check your liability before ordering if unsure. Please check your tracking on all international shipments within 7 days to follow their progress and determine if it is being held by your local customs dept. or on their behalf by the Postal Service, who you will need to make contact with using the provided tracking number.

Please Note: Other than exact replacement OEM carburetors, all Mikuni Aftermarket Carburetors and Tuning Components are sold “As Is” for Off Road / Racing Use Only and are not intended or approved for use on vehicles operated on Public Roads or in locations where applicable engine tampering and anti-pollution laws apply.



Additional information

Select Choke Option

Kit with Knob Choke, Kit w. Cable Choke

7 reviews for Kawasaki KLR 650 Mikuni TM42-6 Flatslide Pumper Carb Kit

  1. tony bamford

    thank you tom for all your help i have installed my new hsr 42mm mikuni followed your instructions on install and set up was not too hard just have to take time and not rush main jetting was spot on idle jet i had to go down to 22.5 bit off grinding thank god for the dremel opened up the air box that was easy how far you go is up to you more air more power did a few short runs few minor adjustments and wow oh my god this is unbelievable i am still in shock the power gain is off the scale you have no idea this bike has been transformed thank you mikunioz

  2. Glenn Kington

    thanks Tom…awesome carby..instant wheelie machine.. power gain is huge with a huge WOW factor as well… a special thanks for all your help and advise..your the real deal…not just a company that sells a carby and says “see you later” or “i dont know,thats not my problem”…you back your products with help and advise which is very rare these days…i cannot believe a stock motor has this much power…dont just take my word for it watch
    https://youtu.be/b9uUxFTeGK8 and see for yourself

  3. Rod Clark

    As has been said by both Glenn Tony and Tom this carby is of the scale do yourself a favour and fit the Mikuni Carby it is great to know that I can come around a corner see a pothole or a log on the track and be able to give the 2017 KLR 650 STALLION thats right Stallion as she is no longer a Pig in 2 gear she lifts her front leg and I’m running Highway gearing 16t on the front sprocket ( will now be changing the Rear Sprocket size as it’s got so much power just to bring to cruising RPM’s down just a bit more ) a quick flick of the throttle and up pops the front wheel so no trying to stop the Stallion and coming to a flying stop going over the handlebars.
    Thank you to both Tom Glenn and Tony I was having a hard time getting the tuning spot on Glenn was such a great help with it we spoke many times on the phone and nothing was a problem for him.
    I took the 2017 KLR 650 Stallion over to Tassie for a Tour of Tassie with the Brother with his KLR 685 BIG BORE and with This Mikuni Carby I left him standing Still he was in awe of the amount of power that the Mikuni Carby has given to the Stock KLR 650 over the 685 big bore one can only dream what a Mikuni Carby on a 685 big bore would be like.
    Thank you Thank you Thank you

  4. Tom H (verified owner)

    Wow big thanks to Tom and the guys a Mikuni oz for all the help with setting up the carb I must have called them 50 times and nothing but helpful information (didn’t realize how important it is to actually aim the pump nozzle).Now to the carb holy sh*t I found what was missing in my diet raw power.This thing will not only change your bike but it will chang your life.No longer will you fear being dusted off at the lights by a ct110 postie with this carb on.this carb fixes what’s missing from the klr response and a big hit of power all the way though the rev range.Yes you will need to have a play with the jets and cut your airbox but it’s all worth it in the end.You will all so lose some fule Range as well so I would look in to a rotopax or a lager tank if you do the big rides to nowhere but so far has not bothered me. So say good bye to your rear tyre, license & wife because you will probably never see them again when you fit this carb.I can’t recommend or be more happy with Mikuni zo and the carb

  5. Dionisis K.

    Running a KLR 685 supermoto as a commuter and fun bike here in Greece, the addition of this carburetor made a tremendous difference on the way the bike behaves and responds. Full-range torque, the feel of the bike’s potential on your right grip, the throttle response, the acceleration, are just the first things you will notice. The acceleration comes hard but in a “controlled” manner, meaning that twisting the throttle hard at 2nd gear’s compression point (even with “highway”-longer gearing) will get your front wheel in the air but not sky-high in order to fall, and definitely not if you do not want it to. The fuel consumption is significantly improved. I believe it is slightly better than the cvk, with a full tank and the cvk i could go from home to work and back 5 times – which I did with the mikuni this week and even going to work from longer distances than my main one. If you are running a loud muffler, expect a small dB increase and a deeper smooth tone. For fitting, you may watch Glenn’s video on YouTube “KLR650 Mikuni pumper fitment” where he demonstrates the complete process and the minor fitting issues you will face. I believe that this carburetor kit is a “must-buy” for people who go on dirt or on “adventures” and for those commuting that want to take advantage of their 650 (or 685+) full capabilities and potential. But just because “a picture is worth a thousand words”, when I complete some final tweaks on it, I will also upload a video of my 685 on YT so you can get a glimpse of what you should expect on a 685 with Mikunioz’s little miracle!

  6. Lee Powell

    Unbelievable went from a slug (Lams) to a monster, I spoke to the guys at Mikunioz about my setup, and they made adjustments before they sent it out.
    To be honest I wanted to believe the hype but deep down I was not expecting the improvement I got straight away, I thought there was going to be a lot of stuffing around and still was expecting to be somewhat disappointed, nothing could be further from what actually happened, I fitted the carb ( had to make adjustments to the floats as it was overflowing the bowl), pushed the start button and that was it. I would say it was 90-95% straight out of the packet.
    I would like to also thanks Glenno, without his youtube videos I probably would not have known about this.

  7. Paul Harper

    I want to thank you all at Mikunioz for the work that you do putting together these carburetor kits for all the big cc Japanese thumpers and I want the world of KLR650 faithfuls out there that if your not running this carb kit on your bikes that you are leaving so much low end torque and top end RAW power still on the table that it truly is unbelievable and words can’t describe what an animal this carb has turned my bike into. I tell you though if you are still learning or don’t have experience on bikes to beware. It is so worth the air box and the little grinding to be done for the power you’re going to gain so far out weighs that mod work. I went one step farther. When I had the starter solenoid and relay off and back out of the way (for the grinding) I took the two bolts out that held the bracket that held them both and drilled a 1/4 to 5/16” hole at the almost very top just to be able to slide my screw driver through which made it so much easier to turn the air mixture screw I put a little piece of double sided tape in the mixture screw where my screw driver goes to turn it and the screw driver just stayed right there, no hunting with my flashlight to keep finding it the tuning went so much faster I just could not believe it. The way Mikunioz sets up these kits with the information the customers provide I bet there’s 8 or 9 carbs work great rite out of the box mine did I adjusted the accelerator pump nozzle in the throat and I checked the idle circuit it was just a hair rich but it was 50 degrees and here in Louisiana USA it gets to 100 degrees often so I left the pilot jet be adjusted the idol went and checked the main and never had to touch a thing. The front wheel goes air borne 1st and 2nd with just a twist of the throttle just like the good people at Mikunioz say it will and if I hit it right 3rd gear as well and I weigh 245lbs. Thank you all and if you own a KLR650 do yourself a favour spend that couple bucks to get this kit and you’ll have a beast just like I do now. One shout out to Glenno for it not for your videos on YouTube I would still be fighting that CV and no where near as happy of a man as I am now.

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