Update on Fuel gauge repair and electrics too
The fuel gauge in my scooter was not working. The problem may occur if the voltage regulator is faulty and thereby high voltage generation. This gets augmented if the battery is also open and it consumes nil current for charging. The bulbs will get brighter on acceleration and will get fused. In my scooter all the electrics were faulty. Referring service manual of a Hondas NH 125 available to download freely, I first changed the voltage regulator and resistor. It’s essential to check the grounding using multimeter and checking the continuity in the wiring loom. I checked quite a few wires in the loom, oil; level switch, ignition switch and much more with a multimeter referring this manual
http://www.hondaspree.net/other/Honda_NH125_Service_Manual.pdf. (Almost identical to kinetic Honda)I hope the moderators would allow pasting the link here for the probable benefit of others.
The fuel gauge was also checked and repaired.
First the meter assembly is dismantled and in the process a plastic retainer broke.
View attachment 209184
View attachment 209185
View attachment 209186
View attachment 209187
View attachment 209188
View attachment 209189
View attachment 209190
View attachment 209193
View attachment 209191
View attachment 209192
Purchased another meter assembly from scrap market, cleaned everything and used its case. The meter glass was replaced with new. The speedometer was working OK.
The fuel sensor had a problem. Though I bought a new one, I tried to rectify the old one. The resistance between the two ends of the fuel sensor unit for float movement between full and empty must be between 4 ohm to 110 ohm. It’s a variable resistance and the wiper was having loose connection with the wire wound resistor. I adjusted and bent the wiper towards the coil and the problem was rectified. The variation of resistance between the lower and upper positions was now linear. There are two wires from the sensor unit. They are yellow-white and green. Green wire is grounded. Yellow-white is the wire going to the meter.
Tank empty------float down-------high resistance--------110 ohm
Tank full----------Float up---------low resistance--------4 ohm
View attachment 209194
View attachment 209195
Unless this is set right the fuel gauge won’t work properly. Also checked the continuity of wires to meter console.
Now the fuel gauge part.
View attachment 209196
View attachment 209198
Note that three connections are required for the meter to operate. If any of the three wires are faulty the meter won’t work. Visually, the calibrating resistors have burnt. They need replacement. The resistance value is 75 ohm and 63 ohm. I used flame proof resistor available in gray color. To increase the wattage, instead of one single 63 ohm, I used two numbers of 120 ohm in parallel. Also for 75 ohm, I used three 220 ohm in parallel.
View attachment 209197
To check its working, apply 12V directly to black and green wires of meter console. The yellow-white wire when connected to ground shows full. The yellow-white when detached from ground shows empty. The meter is now working OK.
I have not taken a photo of the resistance soldered. The problem is when you are working alone, either you can do the work or take photo. I took photo after some major work. Photos are available in either my phone or a digital camera and have lots of photos. To sort it is a nightmare.
Assembled everything, changed all the meter bulbs and the new meter glass and the meter console is complete. Later fitted it to the painted meter panel and finished the console.
View attachment 209199
View attachment 209200
View attachment 209201