Here's the specs i managed to gather.
Throttle Body Assy
Vixion's TB assembly is made by Mikuni and on it you can find the following:
- Intake Absolute Pressure sensor (IAP)
- Intake Air Temperature sensor (IAT)
- Throttle Position Sensor (TPS)
- Fast Idle Solenoid Valve (FID)
The TB valve diameter is 28mm which is good news since my Honda Tiger GL200 carb is only 26mm, ensuring that the engine won't choke. Judging from the amount of "meat" on the TB inlet, i'd say you can ream out the TB to 30mm safely.
FID is on separate housing from the other three, which is the upper part from the pic above. TPS, IAT and MAP can be found on the lower part and form what Yamaha calls Modulated Air Quantity Sensor (MAQS). Never take off the lower part unless you know what you're doing as you may need to adjust the TPS position. Click here if you want to see the TB without MAQS and FID.
Fast Idle Solenoid Valve
There are two pins from FID and it doesn't matter how you connect them to the ECU. I can't really tell exactly for now, but i'm willing to bet that it's just a simple on-off valve, not the PWM type.
You can also find the idle air screw on the other side of the TB. My initial plan for now is to only use FID for warm up enrichment, perhaps via a simple manual switch or use the B&G On-Off setting. That way, just like a carb choke, i'll only activate it on cold starts. Let's see if that works.
On normal condition, you'll measure around 31.5-38.5 ohms between the pins. Mine is 35.7 ohms so i'm safe.
Intake Air Pressure Sensor
Intake air pressure sensor or MAP (manifold absolute presure) sensor can be found inside MAQS module. MAQS module has five pins labelled V, T, G, M and A as shown below.
V is the 5 volts reference input for TPS and MAP while G is the ground pin for all the sensors. MAP sensor output is on pin M. When supplied with 5 volts between V and G, pin M will output approximately 0.789 volts@20kPa and 4.000 volts@101.32 kPa. That's already two mapped values so i won't have any problem making Megasquirt's kpafactor file there.
Below here is the internal diagram for MAQS module.
Throttle Position Sensor
TPS output is on pin T which will output approximately 0.63-0.73 volts at closed throttle.
Intake Air Temperature Sensor
Between pin G and A, you'll find the IAT sensor's resistance. Unfortunately, the manual only says that it should measure around 5.7 - 6.3 kOhms without any further info on the temperature (WTF Yamaha?!). Funny that i got only 1.78 kOhms at room temperature.. I guess i'll have to measure myself to find the values for Easytherm input. It'll be a bit challenging as i can't take off the IAT sensor from the TB. Perhaps 30 minutes in a refrigerator and a thermometer would help. I have managed, however, to find Yamaha XF50 scooter manual that says 5.7 - 6.3 kOhms at 20 deg Celcius while another Yamaha bike manual, YP250, says 2.21 - 2.69 kOhms at 20 deg Celcius. If i have to make a choice, i'd follow YP250's at it's closer to my own measurement.
Worth mentioning is that the Yamaha Vixion manual i'm referring to may be outdated. I downloaded it from our local Yamaha website where i got a Vixion part catalog as well. When i ordered the EFI parts using the part numbers i found on the catalog, i was informed that some of the numbers have changed. TB assy is one of the parts that changed so perhaps the IAT sensor changed as well.
edit:
I googled "2.21-2.69 Air Sensor" as keyword and found more values for Easytherm input!
> -20 deg C = 13.6 - 18.4 kOhm
> 20 deg C = 2.21 - 2.69 kOhm
> 60 deg C = 0.49 - 0.67 kOhm
> 80 deg C = 0.29 - 0.35 kOhm
It seems that i'm on the right track. This post about Yamaha WR25X mentions that it should be around 10 kOhm at 0 deg C and it falls to the correct range on the values above.
Coolant Temperature Sensor
The CLT sensor looks quite similar to the one on my 4-GE engine.
On the body, you'll find 3P20 and 179700-0480 markings.
It has only two pins and it won't matter how you connect them to the ECU. The manual says it should be 310-326 ohms at 80 deg Celcius.
Using the markings on the body, i managed to find more specs for this Denso sensor from the Yamaha YP125 manual.
> 2.32 - 2.59 kOhms at 20 deg
> 0.310 - 0.326 kOhms at 80 deg
> 0.1399 - 0.1435 kOhms at 100 deg Celcius
Sweet, three mapped values, good for Easytherm input. When i measured at room temperature, i got 1.54 kOhms so i guess i'm good.
Fuel Injector
This is a 6-hole injector with 3C11 marking on it. Unfortunately, i can only inform you that it measures 12.5 ohm on the pins, meaning that it's saturated type. You can connect the pins anyway you like.
I'm still looking for the exact flow rate but i'm guessing it's around 100 cc/min. If i plug that value to this calculator, it will be enough for up to 15 hp which is just about the same value as Vixion's advertised hp. It's barely enough for my Honda Tiger as it outputs 16.2 hp. Any engine mod done later will ensure the need to upgrade the injector.
Fuel Pump
This is an in-tank fuel pump with integrated fuel pressure regulator (FPR) which will keep the fuel pressure at 250 kPa (36.5 psi), a bit lower than the typical car engine. The FPR is kept in place with the black plastic clip. The fuel level sender is also integrated to the fuel pump assembly.
There're four pins found, designated as the following:
The fuel float is attached to a variable resistor that measures 7.4 ohms at full and 95.1 ohms empty on the pins. Well within the manual specs of 4.0 - 10.0 @ 20deg C full and 90.0 - 100.0 @ 20deg C empty.
You can pull the FPR unit out after you unhook the black plastic clip that holds it in. This is the FPR unit. It has A3H1I6 markings on it. By the looks of the fuel outlet, it seems inapplicable for external use.
This is where the FPR plugs in. You can see two rubber 0-rings sealing the FPR.
The fuel pump itself seems applicable for external use, with the input on one end and the output on the other. It has the following markings:
1100-00782
11082906 C1
Made in China
Last but not least, here's how the fuel flows on the pump assembly.
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