Emily Posted November 27, 2020 Posted November 27, 2020 hi guys! this is my first bike and my first experience with this kind of thing, i’ve had a few issues so far with the battery but never with the fuses. yesterday i went to take my bike out for a spin, it started and everything fine but as soon as i went to take off everything cut out and the thing completely died. me thinking it was the battery (as this has been an issue before) attempted to jump start the bike but got nothing. i decided to take a look at the fuse box and one by one checked the fuses, everything was in tact besides the main fuse. i took it out and replaced it not thinking much, but when i hooked the bike back up to the battery i watched as it instantly melted. it was getting late so i had to leave it at that. i came back to it this morning and decided to check over all the wires, checking for any loose connections or anything that could be exposed or any visible damage. i’m not really sure what i was expecting to find, and was mostly just being nosy as i haven’t had a good sit down and a look at everything before. i’m completely stumped as of what to do next though, i’ve been staring at the thing all morning and haven’t made any progress with it. the fuses are 15a (and my bikes a mutt mongrel 125 if that means anything) any advice would be really appreciated Quote
onesea Posted November 27, 2020 Posted November 27, 2020 Visual check is a good start. How long have you had the bike is it under warranty? Do you have a multi-meter? What's been the issue with batteries? Was the ignition on when fuse melted? Does it melt with it off? Have you changed anything since you last rode it? Sounds like something is shorting or earthing to me the question is where... 1 Quote
Emily Posted November 27, 2020 Author Posted November 27, 2020 i don't have a multi meter i’ve had the bike since march but didn’t get much use out of it for the first few months. my previous battery couldn’t maintain its charge so i just went ahead and bought a new one and it’s been perfectly fine since the ignition was off when the fuse melted. i haven’t changed anything at all. Quote
onesea Posted November 27, 2020 Posted November 27, 2020 3 minutes ago, Emily said: i don't have a multi meter i’ve had the bike since march but didn’t get much use out of it for the first few months. my previous battery couldn’t maintain its charge so i just went ahead and bought a new one and it’s been perfectly fine since the ignition was off when the fuse melted. i haven’t changed anything at all. Did you changed battery and fuse started melting? Or has new battery been ok until now? Previous battery did not do this? Can you change back to original battery see what happens? Is it exact battery swap? You have not accidently switched any wires round when changing batteries? The new battery was not reversed terminal battery they are out there same shape but opposite terminals... I know these questions seem daft but easy mistakes to make... My next step would be WD40 and multi-meter and wiring diagram. Stuck relay? Something with ignition barrel? Melting a 15amp fuse quickly is major short (I would leave new battery disconnected, unless investigating). Someone will be along shorty to say how bad liberal use of WD40 is (it works for me) and some more intelligent suggestions, think I have double checked the basic. Quote
TimR Posted November 27, 2020 Posted November 27, 2020 Double check that it is meant to be a 15A? ( Owners manual) Most bikes i know even 125s have a 30A as a main fuse on the solenoid 2 Quote
Emily Posted November 27, 2020 Author Posted November 27, 2020 1 hour ago, onesea said: Did you changed battery and fuse started melting? Or has new battery been ok until now? Previous battery did not do this? Can you change back to original battery see what happens? Is it exact battery swap? You have not accidently switched any wires round when changing batteries? The new battery was not reversed terminal battery they are out there same shape but opposite terminals... I know these questions seem daft but easy mistakes to make... My next step would be WD40 and multi-meter and wiring diagram. Stuck relay? Something with ignition barrel? Melting a 15amp fuse quickly is major short (I would leave new battery disconnected, unless investigating). Someone will be along shorty to say how bad liberal use of WD40 is (it works for me) and some more intelligent suggestions, think I have double checked the basic. the battery has been perfectly fine since the swap, i’ve had no issues with it at all. it isn’t the exact battery swap as the one that was in there previously had nothing on it at all to help me identify what the heck it was and it looked really old too. i bought my bike second hand so perhaps he swapped out the original battery for the tatty one i got with the bike.. i’m not too fussed though, the battery was a reasonable price and i could tell my bike was thankful for the new one. i did as much research as i could and tried to get a close of a match i could find. i’ve been using this battery for a number of months now without any issues with it, so no concerns there i definitely didn’t make any accidents when swapping the battery and i’m confident i connected everything how it should have been. thanks for those tips! i’ll check it out. love investigating all this to be honest as much hassle as it is 2 Quote
Stu Posted November 27, 2020 Posted November 27, 2020 For the main fuse to be popping as soon as you connect the battery there must be a live wire going straight to earth somewhere or a badly corroded connector I would start checking all the wiring and pull all connectors apart 2 Quote
WD-40 Posted November 27, 2020 Posted November 27, 2020 2 hours ago, Stu said: For the main fuse to be popping as soon as you connect the battery there must be a live wire going straight to earth somewhere or a badly corroded connector I would start checking all the wiring and pull all connectors apart Yeah I agree. If the main fuse is blowing, a main 12V wire must be touching ground. Either touching the frame or touching a ground wire. Usually a wire rubs through it's insulation and touches the frame, but it can also happen inside a connector where there's a bad connection and that causes the connector to melt and two pins can touch. You can check visually or you can use a multimeter. You can get a multimeter for less than £10 so worth getting one. If you use the multimeter, disconnect the bike's battery, take the fuse that's blowing out. Put the multimeter on continuity (the beeping sound), or put it on resistance. Connect one of the probe to the negative battery wire. Connect the other probe each sides of the fuse holder where you took the blown fuse out of. There will be continuity on one side of the fuse holder. The side that has continuity is where the problem is. When you know what side the problem is on follow the wire and look for damaged insulation 1 1 Quote
Emily Posted November 30, 2020 Author Posted November 30, 2020 (edited) thanks for all your help guys! still figuring it out Edited November 30, 2020 by Emily 1 Quote
KiwiBob Posted November 30, 2020 Posted November 30, 2020 If the fuse keeps blowing you've got a short circuit somewhere. 1 Quote
Emily Posted November 30, 2020 Author Posted November 30, 2020 1 minute ago, KiwiBob said: If the fuse keeps blowing you've got a short circuit somewhere. okay thank you! the bike actually turning on felt like progress so just got a bit excited Quote
WD-40 Posted December 1, 2020 Posted December 1, 2020 A common area where wires rub through is around the headstock. The headstock is the part of the frame that the handlebars and front suspension pivot on. The wiring loom gets pulled because of the handlebars turning and that causes the wires to rub against the frame and wears away the insulation. Have a close look at the wires in that area for any signs of rubbing. Quote
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