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VFR400 NC21 Need Help

Posted: Thu Oct 05, 2017 6:07 pm
by Wolffe
Hey I am quite new to restoring a motorbike, I chose an NC21, Yep I know a terrible idea :grin: but I figured its cheap, a honda V4 and if I screw it up at least I didn't spend too much, the engine runs sweet and the electronics are all great apart from a none functioning temperature guage anyone know the possible cause of that?

I also broke the gear lever, not sure if its just because of old brittle metal but it completely snapped along one section when I switched down into first :o :whistle: and im struggling to find the part available? does anyone know if this part was the same on other models or anywhere I can find it? Image
Other than that all it needs is a new rear light lens, some new tires and tire valves, a new mirror and a damn good wash.

Re: VFR400 NC21 Need Help

Posted: Wed Oct 11, 2017 6:16 pm
by Neosophist
Hey there.

Gear levers are rocking horse, let me know if your struggling to find one and ill see what I can do. It shouldnt snap from being "old" more likely it was bent and re-straightened at some point weaking the aluminium.

Temperature gauge shouldnt be too hard to diagnose.

It's most likely to be

1. bad gauge (wiring ok)
2. bad wiring to the gauge (gauge ok)
3. both of the above.
4. bad sensor


The gauge is quite simple, i believe off hand its only 3 wires.. ground power and sense... the sense wire connects to the thermostat housing on the upper right side of the engine... look for a single bullet style connector to a sensor.. make sure its connected and not corroded away etc.. this can also be your first diagnosis test

with the igntion siwtch on (engine doesnt have to be running)

pull the connector off the sensor and use a bit of wire to connect the sensor to a good metal bolt (ground point).. if the gauge and wiring are ok the sensor will read full hot (dont do it for too long it can break the sensor)

this would show that the sensor is likely at fault...

no movement of the gauge shows theres probably an issue with the gauge or the wiring to the gauge.

id try that first

Re: VFR400 NC21 Need Help

Posted: Thu Oct 12, 2017 7:11 pm
by Wolffe
Neosophist wrote:Hey there.

Gear levers are rocking horse, let me know if your struggling to find one and ill see what I can do. It shouldnt snap from being "old" more likely it was bent and re-straightened at some point weaking the aluminium.

Temperature gauge shouldnt be too hard to diagnose.

It's most likely to be

1. bad gauge (wiring ok)
2. bad wiring to the gauge (gauge ok)
3. both of the above.
4. bad sensor


The gauge is quite simple, i believe off hand its only 3 wires.. ground power and sense... the sense wire connects to the thermostat housing on the upper right side of the engine... look for a single bullet style connector to a sensor.. make sure its connected and not corroded away etc.. this can also be your first diagnosis test

with the igntion siwtch on (engine doesnt have to be running)

pull the connector off the sensor and use a bit of wire to connect the sensor to a good metal bolt (ground point).. if the gauge and wiring are ok the sensor will read full hot (dont do it for too long it can break the sensor)

this would show that the sensor is likely at fault...

no movement of the gauge shows theres probably an issue with the gauge or the wiring to the gauge.

id try that first

Thanks for all the help got the gauge working was a faulty connection, much appreciated, still unable to find that part i need to actually be able to change gears again, searched high and low all over the internet, if you can help at all with that I would be thankful :grin: