Posted by Reggy Bodden on December 11, 2017
● NEW 2018 MODEL YUMINASHI / KEIHIN 31MM THROTTLE BODY SET
FOR MSX125/SF ● GROM125/SF ● MONKEY 125
Because the best is only good enough!
With the new 2018 model 31mm throttle body for GROM125/SF, MSX125/SF & MONKEY 125 the YUMINASHI R&D worked a TOTAL SOLUTION out for the GROM tuner that covers all issues with upgrading from the stock throttle body in to a larger version which is usually in combination with a big bore kit.
The first very noticeable difference compared to the formal 31mm throttle body is that the typical IACV valve from the 31mm throttle body is gone, and has been replaced by an air adjust screw in the same fashion as you can find them in a carburetor. Like this it's really easy to get your idle mixture right on your GROM / MSX or SF with a big bore.
The 2018 Yuminashi 31mm throttle body is now also plug & play ready to install the stock injector type, which is a B-type injector, in the new throttle body and to connect with your wire harness, so there is no need anymore for the use of a wire loom.
※The injector isn't included in the throttle body set.
The new 2018 injector joint which comes with the set is plug & play ready to install the B-Type injector and to accept the stock MSX/SF - GROM/SF - MONKEY 125 fuel hose.
The black button (Part No. 14566-K26-B00), which comes with the set, allows you to make the choice if you want to have the injector in the throttle body, as you can see on the pictures above, or the classic way in the manifold.
If you are looking to make the most horsepower, then a downdraft setup with the throttle body directly installed in a vertical line on top of the cylinder head with the injector installed in the throttle body will allow you to get the most horsepower. (Picture below in the middle)...
※ Manifold, injector & thumb idle adjuster screw on the above pictures are optional and for illustration only.
A stack is machined inside the throttle body to improve the venturi to get a ram air filling effect.
With the new 2 cable bracket on the 2018 Yuminashi 31mm throttle body you can now install both your throttle cables properly on your MSX / GROM / MONKEY125 in combination with a 31mm throttle body.
The 31mm throttle body comes with the SPECIAL YUMINASHI SENSOR BLOCK INSTALLED to allow easy AFR tuning/rpm pickup when cruising around and whacking the throttle open without any hiccups, the torque will be right there! Stunt riders love to have the torque right away starting from low RPM's and without this sensor block installed it will be very hard, not to say "impossible" to get this result, certainly with the stock ECU installed!...
A stock CBR150R throttle body can be used as an alternative, and many vendors are selling these all over the world, but it’s really hard to get your tune right, certainly as said above with the stock ECU installed.
The main reason for the Yuminashi R&D to start with an improvement on the 35mm, and also on this Yuminashi 31mm throttle body, was to solve the issue of tending to run very rich while running lower RPM's on a stock ECU and this with about any injector type.
It was very hard then to pick up the RPM's if you suddenly open full throttle. The formal generation 35mm throttle body was also tended then to run quiet lean in the higher RPM region where we want to see the opposite actually with a well balanced air fuel ratio engine, so the use of the newly developed sensor block is utmost recommended!...
The 3 connector wire loom which comes with the set makes it really easy to connect the throttle body to your stock wire harness.
The 5 pin connector connects on the large TP sensor on the throttle body, the 3 pin connector connects to your wire harness, and the 2 pin connector connects to your MSX/SF - GROM/SF - MONKEY 125 Intake Air Temperature sensor which is located at your air filter box.
■ THIS PRODUCT INCLUDES FREE SHIPPING WITH DHL TO ANY LOCATION IN THE US & CANADA, AND FREE POSTAL EXPRESS SHIPPING TO ANY OTHER LOCATION WORLDWIDE!
All prices are in USD