Description
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 flatspots. These Mikuni carburetors are correctly sized and easily fitted to your KTM 640 stock Mikuni CV air box when using the silver anodized air-box adapter. This adapter is fitted prior to delivery when purchasing complete kits. For this Mikuni carburetor to operate correctly the motorcycles air box should be opened up to allow more air flow in. The kit also comes with throttle cables and a 1/4 turn quick action throttle. There are jets provided for fine tuning and a new pump nozzle which must be changed. 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 included what we have found to be a range of jets to allow you to tune to most variables.
The TM42-6 will accept your standard Mikuni BST choke cable where if running a different carb at present or if also requiring a new enrichener cable, there is also an optional knob choke or short cable and bracket that can be purchased separately and found in the “TM42” drop list option under “TM Flatside Pumper Carbs” in the main menu.
Some international models where fitted with different carbs having dimensions not matching the Mikuni BST and if at all in doubt when referencing the dimensions picture, we supply the TM42 at A=46 B=102 and D=58mm. We do have a range of different size sleeves for other applications such as 62mm, being as close as we can get to the Dellorto 64mm dimension, that can be supplied in place of the 58mm where also if running a big POD you can request we ship the inlet sleeve loose and you then buy a POD to suit the carbs 65mm inlet diameter. If replacing a Dellorto you will also need to purchase separately either a knob or cable choke assembly.
You will instantly experience better throttle response, improved acceleration, increased horsepower and torque. In a number of instances Dyno tests have shown improvements of up to and over 25% when fitted to OEM carburetored engines.
IF NOT WANTING TO PURCHASE THE KIT IN ITS ADVERTISED FORM PLEASE FOLLOW THE DIRECTIONS BELOW.
If wishing to modify your existing KTM cables to suit the Mikuni TM42-6 or use a POD filter rather than the original air-box you can purchase the carburetor, tuner jet kit and or what ever other components you want individually by following the directions below.
On the main menu to the left of the page, hover over the carb listing for TM Carbs with Accel Pump and then select TM42-6 from the drop down list. When clicking on any individual size Mikuni carb from the drop down list it will put you into a page showing not only the Mikuni carb itself but also any items relevant to that carb, being Mikuni jets, Mikuni flanges, Mikuni carb tuner kits, Mikuni cables , Mikuni throttles, Mikuni air-cleaners and a range of Mikuni carb to OEM air box adaptors etc to also suit. This also makes alternate jet selection easy for you if you have your own spec as only the type jets for that particular carb are shown.
Click on the carb itself if wanting to view the full details and or to make your purchase. Then back arrow back in the carbs main page and go into the tuner kits, which show in the sales drop down list the jetting kits we have for confirmed suitable engines for that particular carb. Again thoroughly read the tuner kit description.
If you’re comfortable with making a purchase of the carb, tuner kit any or other associated components, order it on line or otherwise please call us to further discuss your needs on 0747712677.
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.
Garry De Vries –
This Carby Kit is an essential for the KTM640adv and any 625 engine I feal, its the most important area that get’s over looked or neglected. The performance gain is massive improvement in torque from idle @1500rmp to 3000rpm & above, the power delivery is massive improvement, the ride’ability factor from slow pottering around to power stand jumping & power slides is a plus 10. The original BT40 Carby and its pollution vacuum configuration is hard to setup or fix if its been modified plus over time the wear or lack of Maintenance leads to incorrect Fuelling. I have my KTM640adv Geared up 10% more than stock gearing before the Carby upgrade to take the wild edge of the power delivery now the bike power stand’s in 2nd or third gear with a full fuel load & a 105kg plus rider, I have turned my steering damper down to zero because the power delivery just allows heaps of control when you need it, power slides are much easier to control, the engine will sit on any RPM across the range & it has smoothed out the Engine, it has significantly reduced the Engine vibrations through foot pegs, I have removed the rubber peg’s. Now the installation look’s tough but is actually not that hard. You remove the old cables & BT40, the new Cables run down the right side under the Tank OK, The original front Inlet Mount & Air box rubber coupling are used, you just need to ensure the New Carby is as upwrite as possible and ensure it does not lean forward toward the engine too much, Don’t be scared to start on the lower Jet’s as my Engine setup Ran best with 155 Main Jet a Leaner Main Needle 98, the leaner pumper jet. The idle mix setting I did by ear & sight, a simple trick is to slowly increase RPM from idle too 3000,rpm so as not to use the Pumper jet & check the engine runs smoothly in this range, the engine should not blow black smoke when twisting the throttle hard from idle & above. The air box is unmodified except the Stock snorkel or scoop has been removed from the top, I run a TwinAir lightly oiled foam filter with twinAir sock over the top, I have a stock header & an Akrapovic slip on. Now my Original Carby was over fuelling across the entire range, I am amazed the engine handled it, built Tough? now the give away to incorrect fuel carby setup was Valve clearance, it was always needing attention well below the normal 5,000km service.
This Carby Turn’s your 640 into a Dakar bike I recon but with more control over the power delivery, more fun so much so I need to update the suspension now, I ride it like my 450 and need more compression & rebound control due my weight. The Original owner had the suspension modified to 300mm travel front & rear. This has been my project bike for some years now & I have done many Maintenance or part replacement but this modification is by far the best improvement to the adventure bikes it has more reliable power delivery.
It is a big investment but it is well worth it, an important note is this modification may save you expensive engine rebuilds down the track. I have noticed some guy’s do top end early for some reason? My bike has done 47,000km engine is fine. Just a personal opinion I recon this Carby makes the KTM625cc/640adv a better bike to ride than the early KTM690’s because of the improvements in torque & power delivery.