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  • Recommend Air Fuel Ratio's....
(Not possible to adjust without a wideband O2 sensor & gauge)
  • Recommend Air Fuel Ratio's....
(Not possible to adjust without a wideband O2 sensor & gauge)
RRP: $609.47
$574.87 (You save $34.60)
3,170.00 Grams
Usually ships in 1 week
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Minimum Purchase:
1 unit(s)

 Product Description

free-shipping-worldwide-yuminashi.png**Don't use this kit without the Yuminashi high performance coil installed!! If you don't have one yet, then you can order it over here. This kit is not plug&play, you will need to buy a wideband O2 sensor and spend time to properly tune the standalone ECU to fit your setup, exhaust systems and climate condition or you will have to have access to a professional dynamometer tuning service.


**All MSX/GROM125 and MSX125SF/GROM125SF big bore kits available on the market suffer from the restricted cooling capacity of the air cooled engine. 
We strongly recommend to install the largest oil cooler where you can get your hands on.

Keep in mind that if your engine temperature reach 130°C it's no longer possible to get a straight line in your tune. 


The 164cc Ultimate Plus kit is one of the most complete "all-in" starter kit on the market which comes also with a really great price tag, inclusive free shipping worldwide.
The new "PLUS" edition is even a better value for money kit compared to the standard 164 Ultimate Kit because this kit includes the 25/25 tooth 4th gear sports sprocket set (1:1 gear ratio) and this as a serious "plus" compared to the normal/standard 164cc Ultimate version.



● The reason why these included gears are a serious plus is because with the short 25T/25T 4th gear sprocket set you're transforming the stock gearbox with serious heavy overdrive characteristics in to a close ratio transmission with a 4th gear 1:1 sports ratio and with direct result a cooler running engine, the ability to run higher compression ratio's, a lot easier to tune engine and no drop at all if you are shifting from 3th to 4th gear which is a serious issue with the stock 4th gear installed, even with 164cc.

With the stock 4th gear installed you have a serious heavy load in 4th gear and bringing the load down with the shorter sports gear set will mean a serious reduction on engine knock (detonation) and temperature.
If you install this kit in combination with our 30510-K26-000S High Performance Ignition Coil & Wire kit, you will be able to get totally rid of engine knock, and make performance like you never thought it would have been possible with only a 164cc kit on the stock head and throttle body! Please keep in mind that we developed this kit under the assumption and common sense that you will install an aftermarket, better designed, freer flowing exhaust system. Using a completely stock exhaust system on a big bore kit will result in a hot running engine, more sensitivity to engine knock, difficulty in tuning and overall reduction of performance. 

If you install a big bore kit then this 1:1 gear ratio sprocket set is really the first thing recommended to install and this will allow you much easier to get more performance out of it.

● The Ultimate 164 Plus kit comes just like the standard Ultimate 164 kit with the Bluetooth enabled standalone ECU where you can tune on the go with your Android system, and have the choice to create and select 2 different maps.


With the optional Off Run / Map Select Switch you are able to switch back and forth between the both maps on your standalone ECU while you are driving!  

If you don't have the Off Run / Map Select Switch installed, then you can select map 1 with installing the jumper that comes with the kit, and with the jumper removed you are selecting map 2.

(If you use the stock air filter you need to remove the restriction inside the stock air filter like you can see on this video from Motorcycle Projects on YouTube).

● The 6-holes high-flow NLJ injector that comes with the kit guarantee a short and powerful injection and you don't need to install a larger throttle body or EFI controller to control the air fuel ratio because the Bluetooth standalone is programmable (need to order the optional USB Programmer Cable)...


Set comes complete with the SX290  8.2 high lift camshaft, and also with the special high lift valves to make a higher lift as stock possible. 
The reinforced clutch springs that comes with the kit make sure that you don't miss one single RPM.

The 164cc Light Bore piston set is made with a molybdenum coating to be installed in combination with the stock 125cc MSX125/GROM125 or BLADE 125 FI 125cc head and crankshaft.


● These piston rings are produced based on strict Japanes standards and since March 2015 are all rings treated with a hard chromium plating layer (Cr).
To read all details/information about the piston rings you can click on this link.


● The reinforced clutch springs in the kit are meant to replace the 6 stock Honda springs in order to prevent clutch slippage caused by increased HP and torque.

The reinforced clutch spring rates were carefully chosen with daily driving in mind to provide enough pressure to avoid clutch slippage, but not so stiff stiff as to cause hand fatigue.


● The high-lift Yuminashi SX290 8.2 camshaft really makes a difference because the Yuminashi R&D have not only increased the valve timing degrees, but also the intake and exhaust lift, and with a intake valve lift of 8.2mm is the Yuminashi SX290 8.2 camshaft the only camshafts on the market for MSX/GROM125 / BLADE 125 FI which exceeds the maximum possible intake valve lift of 7.1mm for a stock MSX/GROM125 / BLADE 125 FI cylinder head.

To be able to get such a high lift in the stock MSX/GROM125 / BLADE 125 FI head the Yuminashi R&D had to develop special valves to make this higher lift possible without ramming the valve retainers against the valve guides and valve seals.

Because of this, the special High-Lift valves come together with the high lift camshaft as one set.


● The tip from both valves are heat treated and cooled down in a controlled way to improve the strenght.

This set needs to be installed together with the special high lift valve retainers and valve cotters as you can see them in the picture above to avoid contact between your rocker and the retainer.

● The double progressive reinforced valve springs come with the set to avoid floating valves. With the standalone ECU installed the stock RPM limit will be removed and the double progressive valve springs allow you to run safe higher RPM's. 


● The 2017 38770-K26-003 Bluetooth V6.1 Yuminashi Stand-alone ECU / Datalogger is much more as just a replacement for the formal 2016 V8.9 generation.

First of all is the new 2017 V9.1 series compatible on both, the MSX125/GROM125 and the MSX125SF/GROM125SF.

The huge jump forward is in the fact that the new 2017 V6.1 has a Bluetooth connection, and this means that your wide band O2 gauge can read wide band AFR data while you are driving on your Android system!!
This means that you can see the AFR ratio in each and every field, and are able to adjust these fields on the fly with your Android system.

This eliminate basically the need for a dyno since you are able to make all correction while you are driving based on a real life situation/real life load like uphill driving, or driving against a headwind, etc... 

While the software can run with the stock narrow band O2 sensor, we strongly suggest not to do so because it's a total waste of time and money if you are doing so.
The stock 1 volt narrow band sensor isn't able to read accurate AFR reading, so the results you will see on your screen will be far away from accurate/reality with possibly serious engine damage as result!...

If you don't have a wide band O2 gauge yet, then we like to recommend the Innovate MTX-L gauge (please click the link in yellow, not supplied by our company) because this California based company has a basic no nonsense device which can take a lot of vibrations and is perfect to do the job compared to others we tried.

It's also very easy to connect this gauge to our standalone ECU where you only need to connect the yellow wire from the MTX-L gauge to the green wire from our standalone ECU, and after a right click on the AFR meter from the program where you need to select "wideband"  then you can see exactly next to each value in the map how much the AFR ratio is from any particular spot in the map and like this it becomes really easy to know if you have to increase or decrease the percentage from that particular value in the map to get your optimal AFR target.

If you have set your perfect map, then keep in mind that your AFR ratio will change based on the temperature.
With the 2016 IAT enabled version we had made it possible to increase or decrease your entire map based on the Intake Air Temperature (IAT) which works based on the build in IAT sensor from your bike, with the 2017 V6.1 version we have kept this to make your tune possible around the year.

If it's starting to get colder or warmer compared to the temperature when you had set up your map, then go to the program (you need to use the USB tuner Cable for that, software is free), go to "enrichment correction" and enter a value based on the actual temperature to get your entire map back like it was when you had set up the map.
Like this you are able to correct and set up your standalone ECU to run your tune day in, day out.

● Please open this PDF file and use it as a guide to gain both, maximum performance and maximum protection against engine knock (very important). 

You need to order the optional USB Programmer Cable if you don't have one yet (the one from the formal stand-alone ECU generations can still be used), because you will need this cable to make the ECU work based on your local environment conditions! 

If you haven't one yet, then please don't think that you won't need it, you can order it over here...

**Click this link to download the tuning program manual in PDF file...

             Driver install software (1.6M)



                  2017 ECM-BLUETOOTH V9.1 Tuner Setup software 2017 (1.97M)

**Click on this link to download the .msi file needed to install the tuning program.

             map-ecu-icon.png 2017 ECU MAP 8-HOLES LOW FLOW INJECTOR / STOCK THROTTLE BODY with 2 different ignition maps.

warning-sign-small.png The 2016 generation standalone ECU has been superseded by the new V9.1 2017 Bluetooth enabled standalone ECU for narrow band and wideband O2 sensor. 


● Please open this PDF file and use it as a guide to gain both, maximum performance and maximum protection against engine knock (very important).

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