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YUMINASHI 125CC POWERSPORTS ECU PACKAGE (Z125 MONKEY (2018 - 2021))

YUMINASHI 125CC POWERSPORTS ECU PACKAGE (Z125 MONKEY (2018- )) (38770-K0F-T01CS)

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  • YUMINASHI 125CC POWERSPORTS ECU PACKAGE (Z125 MONKEY (2018- )) (38770-K0F-T01CS)
  • YUMINASHI 125CC POWERSPORTS ECU PACKAGE (Z125 MONKEY (2018- )) (38770-K0F-T01CS)
YUMINASHI
$202.36
SKU:
38770-K0F-T01CS
Weight:
241.00 Grams
Availability:
Fast moving item, ships the next day (Except on Sundays & Thai public holidays)...
Shipping:
Calculated at checkout
Minimum Purchase:
1 unit(s)
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 Product Description

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● YUMINASHI 125CC POWERSPORTS ECU PACKAGE (FOR Z125 MONKEY (2018- / 2019 / 2020))

● With this entire package we've got you sorted to get the tune right on your stock 125cc 4-speed Z125 monkey, which includes:

  • The YUMINASHI Powersports ECU for the stock 125cc engine with the .5 software
  • The KEIHIN 120cc/min 6-holes injector (F-Injector)
  • A genuine JOMTHAI 13T Self Cleaning High Carbon Sprocket.

With this package you are getting an entire package specifically developed for the stock 125cc engine which can actually deal with a high flowing air filter, and other exhaust installed.

When you are purchasing this package, you are making a pretty sweet deal, where "sweet" goes much further as a reference to the lower price for this entire package, which is actually lower as what you normally would pay for just a reflash. 

● "Sweet" is the least we can say about this package, because a totally new powerful base map has been created for the auto-tune version of the Z125 MONKEY Powersports ECU where we took all elements in consideration such as the engine temperature, the ratio between engine temperature and performance (or the drop of performance after a certain temperature), the very heavy overdrive which is installed stock on the Z125 MONKEY engine, and to get the best result possible with all of this in mind, even if you have the stock exhaust installed.


● ENGINE TEMPERATURE

● The engine temperature is really important for the bike, because it controls not only the air fuel ratio, but it's also directly related to how much power you can make, so controlling the engine temperature with the new Powersports ECU was really key for us to work this out properly.

If you have a wideband O2 gauge installed on your bike, then firstly we recommend you to look at the Lambda values and not the AFR values, since almost every fuel is a blend with a percentage of ethanol, mostly 10% these days.
This means that if you are are running your O2 gauge in AFR mode and not at Lambda mode you are getting a false result...

● We are mentioning the engine fuel ratio in an explanation about the engine temperature because there is a direct relation between these two.
If you have a wideband O2 installed, then you will see that the air fuel ratio or Lambda values between a totally cold engine and 76°C (168.8° F) aren't stable, it's correcting all the time while the temperature is rising.

Above 76°C (168.8 degrees Fahrenheit) you suddenly will get a stable air fuel ratio and this until something between 96°C (204.8° F) and 100°C (212° F) where the engine start to drop power.

● So with the .5 software installed on the Z125 Monkey ECU we are able to control the engine temperature without the install of an additional oil cooler to make sure your engine always will make the most power, even with the stock exhaust installed.    


● INJECTOR SIZE

● The injector size really matters, and the stock/original 90cc/min injector is perfectly fine if you are not planning to let the engine rev higher as the stock limited 9,250RPM's with the stock/original camshaft installed.

A 90cc/min injector is normally installed on a 100cc or 110cc engine, so if you want to pass the stock RPM range you need to have an injector who can deal with that.

That's the reason why the 120cc/min injector (LINK) comes in the Powersports ECU package for the stock 125cc engine.

 

● Having the right injector size installed is certainly important in combination with a high performance camshaft.

If you install a high performance camshaft you will suck more air in the engine as you do with the stock/original camshaft, which means that you need to have an injector installed with the capacity to balance this out.
This is really important above 80% throttle (TPS) and the .5 software for Z125 Monkey has been worked out in such a way to be perfectly fine to do so.  

※ You need to remove the small restriction tube/pipe inside your stock air filter box!


● ENGINE LOAD / SPROCKET SIZE 

● The engine load is really important about the result/speed you can get out of an engine, and how the base map need to be worked out related to the engine load.

Yuminashi was the first company in the world who saw the problem with the stock/original 15T sprocket on the stock 125cc engine, and to recommend the install of a 14T sprocket.
The 4th gear overdrive installed on the stock/original engine is so huge, that at the moment you are revving the engine in 3th gear, until the RPM cut, and you shift to 4th gear, your RPM's are dropping so low that it never can recover from that.

That's the reason why we recommended in 2013 to install a 14T sprocket, and why we have worked out later on the 4th gear sprockets 1 to 1 sports gear (LINK), since this it totally the solution for this problem.

The sales results however have showed and learned us that you don't want to install a shorter 4th gear sprocket combination, ...even if we give the sprocket away almost for free.

So with the new 2021 .5 Powersports ECU we have worked a solution out for the stock 125cc engine to deal with this.

● The best result we could work out was not with the 14T sprocket, but with the 13T sprocket installed.
That's the reason why the 13T sprocket (LINK) is included in the package for the 125cc engine.

If you install a 14T sprocket, then it still takes forever until you reach top speed, and if you have some head wind, then you still will need to shift back to 3th gear.

With the 13T sprocket in combination with our ECU you don't have that problem anymore.
As soon as you shift from 3th to 4th gear you actually will continue to pick up speed, and if you are comparing GPS speeds on a flat road, then you will see that you will be able with the 13T sprocket to get a higher GPS top speed as ever would be possible to get with a 14T or 15T sprocket installed.

※ Don't look at your speedometer speed, because the speedometer will show about 20% more as your actual GPS speed.

 

● ENGINE RPM LIMITER 

● The RPM limiter has been set at 11,000RPM and this to allows you to run higher RPM's at the moment you install stronger valve springs (LINK) in combination perhaps with a high performance camshaft (LINK), or even an upgrade later on to a big bore kit.

With the stock/original valve springs installed the RPM limiter at 11,000RPM's is pretty much pointless, because if you are passing 10,500RPM the valves will start to float and you will feel that the engine simply doesn't want to make power and higher RPM's anymore, so the best moment to shift with the stock valve springs will be between 10,250 and 10,500RPM. 

※ Some people believe that having the RPM limiter set at 10,000RPM will be safer for the engine in case they misshift from 3th to 2th gear at high RPM's.
If you are revving the engine up to 10,000RPM and you shift from 3th gear to 2th gear instead of 4th gear, then no RPM limiter in the world will avoid that your engine RPM's will go over the top, and you probably will end up with some bended valves, and perhaps a hole in your piston.

So if you are one of these people which thinks that an RPM limiter will save you from that, then we are sorry to inform you that this is a fairy tale. 

     

● HOW TO INSTALL? 

● The install is really easy, you simply unplug/remove the stock ECU, and replace it with the Yuminashi Powersports ECU.
※ Once you installed the ECU, it is possible in some occasions that the engine check light comes on the first time you switch it on.

If you are installing the ECU, then it's always a good idea to reset the ECU, and the TPS (Throttle Position Sensor) as you can see in this video explained by Frankies World for MSX125 SF (same procedure for Z125 Monkey).
Like this you are 100% sure that the ECU will do as where it has been programmed for.


● Installing the injector is very simple, you remove the stock injector, and you replace the stock injector with the 120cc/min injector in the package.
※ You need to remove also the small air restriction pipe inside the air filter box.


● The stock 15T front sprocket need to be replaced with the 13T sprocket in the package and you are good to go.

 
● ONCE YOU INSTALLED THE ECU THERE ARE 3 THINGS TO KEEP IN MIND:

  1. After you have reset the ECU and TPS (LINK) there is more as a big chance that your bike won't run perfectly from the first time you start your bike, since it's in learning mode.
    At that moment you want to make an at least 30 minutes ride with the ECU in closed loop, which is between 0 and 80% throttle, with different RPM's, throttle positions and gear shifts, since it's capable of self adjusting fuel trims and ignition tables while you ride to deliver an accurate performance.

    Don't take it at a long road with the throttle 100% open because you are learning the ECU nothing like this.
    It is a completely autonomous system which means that you don't need to install software and get software updates, data cables, laptops, secondary sensors, etc... 


  2. This specific package is mentioned for the stock/original 125cc engine, but if you would change to a big bore kit with a 2 valve or 4 valve head, then you need to install a larger injector to compensate since the stock injector has it limits.

  3. The Powersports ECU for Z125 MONKEY has the RPM limiter at 11,000RPM, which means that you won't see the RPM limit anymore at stock 9250RPM's
    We recommend to install our double valve springs set to avoid floating valves in the higher RPM zone. LINK 
      

※ Around 80% throttle the ECU will run in open loop where the injector size need to be correct with your engine setup since it doesn't get a signal anymore from the O2 sensor and it won't be able to make corrections.

※ If you installed a big bore kit and you have no wideband O2 gauge installed, then your injector size will be too large if you experience that your engine don't want to make RPM's.
If your engine does want to make RPM's, but have bad low and middle RPM power, then your injector will be to small. 

Both situations are too avoid, and if the injector size isn't right, then the Yuminashi Powersports ECU can't generate a correct map for it....
With this LINK you can visit the injector section for your Z125 MONKEY.


● THIS VERSION OF THE POWERSPORTS ECU IS MENTIONED TO BE INSTALLED ON:

HONDA:

  • Z125 MONKEY (2018- )

※ This ECU is a replacement for OEM #38770-K0F-T01

budget-logo-2.png SMART SHOPPER TIP:

       ※ BUYING MORE THAN 1 PIECE CUT THE TRANSPORT PRICE, AND YOU RECEIVE A 10% DISCOUNT ON TOP OF IT!
       
   ※ B2B:  

  • Purchases between 2 & 4 pieces of this product will receive a 10% DISCOUNT 
  • Purchases between 5 & 9 pieces of this product will receive a 15% DISCOUNT 
  • Purchases between 10 & 19 pieces of this product will receive a 20% DISCOUNT 
  • Purchases between 20 & more pieces of this product will receive a 25% DISCOUNT 

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