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Mikuni TM42-6 Flatslide Pumper Carby Kit

(2 customer reviews)


DR650 96′ to current

The Mikuni TM42-6 HSR flows 17CFM more than the 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 hard starting, hesitations and flat spots.

These Mikuni carburetors are correctly sized and easily fitted to your Suzuki DR650 stock air box when using the silver anodized air-box adapter. This adapter is fitted prior to delivery when purchasing complete kits.


More Information about the TM42 from Mikuni:

“For this Mikuni carburetor to operate correctly the motorcycles air box must be opened up to allow more air flow in. Using a hole saw, a 45mm diameter hole will be a sufficient starting point where alternating between WOT runs with and without the filter access door removed will confirm if you have removed enough material. The kit also comes with throttle cables and a 1/4 turn quick action throttle. The carb comes fully re-jetted for your application with spare main jets for fine tuning. 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 fitted what we have found to be a range of jets to allow you to tune to most variables. Though the TM42-6 will accept OEM choke cables, included in the kit is the optional knob choke assembly.

Fine tuning is generally related to exhaust system with the DR650 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 only usually relate to main jet size and or often pump nozzle. 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.

You will instantly experience way better throttle response, improved smooth acceleration, increased horsepower and torque.  Plus the bonus of better fuel economy. Dyno tests show improvements of up to and over 25% when fitted to OEM carburetored engines. To fully appreciate the potential this carburetor has you must fully read and follow the provided fitment and tuning sheets.”

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

“In the late 80’s Mikuni America 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 carburetors. 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.”

Additional information


Include Extra Choke Knob, OEM Choke Cable only

2 reviews for Mikuni TM42-6 Flatslide Pumper Carby Kit

  1. Dave Impey (verified owner)

    Took a bit to get the tuning all sorted out but Tom at Mikuni Oz was super helpful and I have it as good as it will get, I think. I believe the claims are somewhat optimistic and after talking to some people who know this bike really well won’t be expecting some sort of wheelie monster. Having said that, the acceleration down low is substantially improved. It starts better, idles better and even in top gear it will pull away smooth and strong from 60kph. I love this bike and with this carb I love it even more. It is value for money and I am happy I purchased it. As it comes with a new throttle tube you might want to make sure you have a new set of grips ready as well. Suspension next and then maybe the big bore kit.
    Adventure bike Australia is like Santas workshop for me. All the good stuff and they are always there to help with great advice and direction while you choose how to build your own personal ride. Thanks ABA

  2. Dave Impey (verified owner)

    Short update. Don’t trust your “assometer”. Get it tuned on a dyno. Do all your exhaust and whatever you are going to do then take it in. I thought I had mine pretty good and then something as simple as a new air cleaner and I had issues again. After the dyno where we went up 2 jet sizes and down 2 grooves on the needle it is much better than it has ever been. Great money spent to make sure that expensive carb is giving you the best return on your money. $1400 on a pipe and a carb and $200 extra to tune it? Why wouldn’t you? No way anybody is going to help you sort it without some science giving you the numbers.

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