My bike looks good on a trailer

[Slyer]

You could have replaced a fork seal in the time it took you to type that.

[PirateJafa]

TL;DR

[jono035]

Firstly, the 20A fuse. Because of the way a fuse works, simply as a stop gap should a current greater than the value go through the fuse it will change to an open circuit to prevent the flow of such a large power to whatever its protecting, as long as nothing in the circuit is faulty it shouldn't matter if i use a bigger fuse or a piece of wire of decent cross sectional area. Knowing about these sort of things, and that there was an excess of current which flowed round the circuit, I changed the blown 10A to a different one and placed the 20A in another ones 10A place, which would not matter as long as there are no sudden changes in resistance/voltage in the circuit, which with what I was doing there was not. The reason the other fuse likely blew out was because short circuiting it resulted in a pulse which was, due to its short time scale, of a much larger total energy (and thus current) than a constant flow which is what occurs with the switch, by not doing that with the 20A its unlikely to put through such large current that the fuse would blow if it was 10A and not if it was 20A, and should such a situation occur, it would be very unusual seeing as how nothing significant had changed in the bike and the specific fuse in question that was switched has never had any electrical problems with its circuit nor with the fuse blowing.

Sure, leaving it in there constantly means that the 'protective measure', which is ONLY there for if something goes wrong (in a perfect situation, a fuse is useless as its just extra wire), but in a controlled case where there is little change to the system the changing of a fuse has the same effect as using a differnt piece of copper wire. Feel free to discuss it more with me, when I do know a damn fair bit about electronics and such (or consult the electrical engineer postgrad we have in the club)

As for the maintenance, in general I'd prefer to do maintenance myself, but theres two things that takes, time and money. Don't have much of the second, and at the moment with uni the first has dried up a bit too. Things like an oil change I'll be buggered if I'll pay someone to do, unless the labour is free and I only pay for the actual fluid/parts. Its more a case of my mother deciding she doesn't like the bike being unwarranted and such simply because I can't afford the seals+oil to do it myself. On the point of costs, it depends on how much it is after being weighed up, if something is ridiculous in cost then theres a good chance I simply would say "nah, dw, I'll do it myself", but the forks MUST be done, and because my parents wish it done now rather than 'sometime in the future' (the current situation), it will be done by a shop.

The other thing is that if something else breaks, yes its their fault, but if something goes wrong with what you personally did (such as you dented your forks, put too much oil in, etc), then you can't then go to someone and say "hey, you caused this, its written down in this piece of paper, you fix it and any other problem which occured due to it", and have them be required to do so

Just re-read that and yeah, you're pretty much fine providing that the one that blew was replaced with a fuse of the same rating. I'd still make sure my first trip was to get a new fuse because 40A in a 10A wire will end with flames.

Edit: Sure, fuses are a protective measure only and thus worthless unless something goes wrong, but the reason vehicles are so rigorously fused is that they have a tendency to burst into flames otherwise when something (cable tie breaks and the wire touchs a hot exhaust, wire dragged into sprocket, wire wearing against frame etc. etc.) does go wrong. 20A fuse = 40A current to blow within 10 seconds. A short on a bike battery through 10A rated wire may not get there at all. Personally, I'd rather not have the possibility of my crotch turning into a fireball on the motorway.

Also, if your mum is going to pay for a mechanic to do the work, get her a quote and spend that money on parts then show up to a fixit day with a couple dozen beers. I've had mechanics screw stuff up with my car a couple of times now (always things that I didn't have the space and equipment to do myself) and best of luck convincing them they've done anything wrong. One of those places was Midas, too.

It WILL cost shitloads for a mechanic to do all of that. $1k on a bike worth $2.5k at a stretch? Jesus.

[Dare]

This thread made me lol.

Wade, man up and do it yourself.

That is all.

[Real_Wolf]

Just re-read that and yeah, you're pretty much fine providing that the one that blew was replaced with a fuse of the same rating. I'd still make sure my first trip was to get a new fuse because 40A in a 10A wire will end with flames.

Edit: Sure, fuses are a protective measure only and thus worthless unless something goes wrong, but the reason vehicles are so rigorously fused is that they have a tendency to burst into flames otherwise when something (cable tie breaks and the wire touchs a hot exhaust, wire dragged into sprocket, wire wearing against frame etc. etc.) does go wrong. 20A fuse = 40A current to blow within 10 seconds. A short on a bike battery through 10A rated wire may not get there at all. Personally, I'd rather not have the possibility of my crotch turning into a fireball on the motorway.

Also, if your mum is going to pay for a mechanic to do the work, get her a quote and spend that money on parts then show up to a fixit day with a couple dozen beers. I've had mechanics screw stuff up with my car a couple of times now (always things that I didn't have the space and equipment to do myself) and best of luck convincing them they've done anything wrong. One of those places was Midas, too.

It WILL cost shitloads for a mechanic to do all of that. $1k on a bike worth $2.5k at a stretch? Jesus.

First, won't be spending $1k to have it all done, :P, I said those are the things I'd like to have done all at once, have to wait and see first what the problem is (because despite the belief that it is the fuel pump, there is a chance it is something else), and the fork seals need to be done within a timely manner.

Its a case of ease of mechanic vs finding time, sourcing parts, and theres the added benefit of them actually going over the bike and finding out what it is that is wrong. As for mechanics screwing up, completely agree with you, which is why I'm not taking it to a mechanic I don't know.

As for the fuse, I meant while I was testing out what the problem is, this was when it wasn't starting, the fuse that had blown did not have the 20 in it, and the '20' which i only put in while testing to make sure that all the circuits had continuity was taken out afterwards so that I didn't just leave it in there, was replaced with a proper 10A as soon as one could be gotten. Sorry if I didn't make it clear, but absolutely no way would it be a good idea to ride with the wrong fuses put in. The "controled case" in this case is when it was only going to be run for a short time to see if I could get the engine to turn over (seems the switch was really really bad, given it a bit of a clean but not sure if its fully working now or if I might need to replace it), and should the engine have turned over, not even checking if it would catch, it would have then been turned off and would have waited for the 10A

[jono035]

Fair enough.

Even household fuse wire can work, and makes a good substitute if you're blowing one fuse repeatedly. Should even be available from the supermarket for a couple of bucks.

[Ixion]

fuel pump - $hundreds new, maybe under $200 secondhand
tuned - $70 an hour for carby clean and balance on a 4 carb bike; $hundreds
fork seals - $300 or more all up

Wait. What? Fuel pump and carby ? That's not normal. Is this one of those perverted bikes where the tank is not in the proper place ?

If the fuel pump is only to lift fuel and not feed an FI system, it's VERY unlikely to be your problem. Personally in such a case I'd want some very compelling evidence before spending money on it.

[Slyer]

Indeed it is one of those perverted bikes. The fuel tank is in the rear of the bike and you can keep a helmet etc where the tank normally is.

[Danae]

Indeed it is one of those perverted bikes. The fuel tank is in the rear of the bike and you can keep a helmet etc where the tank normally is.

Except that he can't fit his helmet in there.

[motorbyclist]

man the thread title sure is fitting isn't it?

before I begin, it's good wade conceeds that putting a 20A fuse in place of a blown 10A is a stupid idea. It's a good thing that's not what he did, buut in the future he should really be more specific about what he's doing or we can't really help diagnose anything.....

Firstly, the 20A fuse. Because of the way a fuse works, simply as a stop gap should a current greater than the value go through the fuse it will change to an open circuit to prevent the flow of such a large power to whatever its protecting, as long as nothing in the circuit is faulty it shouldn't matter if i use a bigger fuse or a piece of wire of decent cross sectional area. Knowing about these sort of things, and that there was an excess of current which flowed round the circuit, I changed the blown 10A to a different one and placed the 20A in another ones 10A place, which would not matter as long as there are no sudden changes in resistance/voltage in the circuit, which with what I was doing there was not. The reason the other fuse likely blew out was because short circuiting it resulted in a pulse which was, due to its short time scale, of a much larger total energy (and thus current) than a constant flow which is what occurs with the switch, by not doing that with the 20A its unlikely to put through such large current that the fuse would blow if it was 10A and not if it was 20A, and should such a situation occur, it would be very unusual seeing as how nothing significant had changed in the bike and the specific fuse in question that was switched has never had any electrical problems with its circuit nor with the fuse blowing.

Sure, leaving it in there constantly means that the 'protective measure', which is ONLY there for if something goes wrong (in a perfect situation, a fuse is useless as its just extra wire), but in a controlled case where there is little change to the system the changing of a fuse has the same effect as using a differnt piece of copper wire.

In almost a decade of mucking with motorcycles I have never seen a "controlled" case. You have an electrical fault, indicated by starting issues and dead fuses, and have no idea what's the cause of it. How can you be certain that doubling the rating on even a seemingly unrelated circuit is a safe move?

remember that the heat loss is proportional to the square of the current, so a 20A fuse will allow four times the energy to heat up your wiring loom before it begins to fail, and that failure is going to take time which can be on the order of seconds. A short burst of current actually has a good chance of leaving the fuse intact as the "heat" is on for such a brief period that the fuse doesn't have enough time to melt. I've got a few 15A headlight fuses where the plastic got hot enough to melt before the fuse wire finally gave up, after a sustained, heavy load.

When your 10A fuse blew it could have been from a short due to wear on wiring insulation. This is a very common thing to find on bikes, and was present on that aforementioned headlight circuit which experiences no movement and is much younger than your own. It could be that your 20A circuit is also worn, or any heat damage from the 10A blowing has now created a fault in that 20A circuit.

Putting in a 20A is going to cause heating in the wires long before it blows, (remember they all tend to go down the one bundle wrapped in plastic and tape) possibly causing other wires to short. Would you like a quote on buying and installing a new wiring loom, too?

So next time you go about swapping fuses, do consider that unless you've thoroughly inspected the entire wiring loom for defects, and then checked all electronics for similar faults, this is no "controlled" case you speak of - and by that point you should know what's wrong anyway

Feel free to discuss it more with me, when I do know a damn fair bit about electronics and such (or consult the electrical engineer postgrad we have in the club)

I know a damn bit more about automotive electrics than you might realise, and could not only build but improve on some of the older electronic systems our bikes are running - this isn't radio/microwave frequency stuff where I'm happy to admit I have little knowledge.

running a 20A fuse in a 10A circuit, especially when there is an unknown electrical fault, is a stupid idea and I don't care how highly qualified you might think you are.

As for the maintenance, in general I'd prefer to do maintenance myself, but theres two things that takes, time and money. ...... but the forks MUST be done, and because my parents wish it done now rather than 'sometime in the future' (the current situation), it will be done by a shop.

The other thing is that if something else breaks, yes its their fault, but if something goes wrong with what you personally did (such as you dented your forks, put too much oil in, etc), then you can't then go to someone and say "hey, you caused this, its written down in this piece of paper, you fix it and any other problem which occured due to it", and have them be required to do so

fair enough, get the forks done if mum's paying but good luck getting a mechanic to admit they've fucked up.

First, won't be spending $1k to have it all done, :P, I said those are the things I'd like to have done all at once, have to wait and see first what the problem is (because despite the belief that it is the fuel pump, there is a chance it is something else), and the fork seals need to be done within a timely manner.

Its a case of ease of mechanic vs finding time, sourcing parts,...

$70 an hour. Is it really worth the time saving to have the mechanic playing diagnostic and do you really expect them to waste time doing a thorough search for cheap parts?

On the rare occasion I do get a mechanic to work on my bike(s), I know he has already done the same job successfully to another bike of the same model/type (so he won't waste hours learning on the spot how to, say, access my carbs), and I will know the cost of or supply the parts myself.

[jono035]

You're quite right there, Andrew. The other side of it is that the fault could have damaged a connection or wire somewhere that is loomed up with the 'known-good' circuit.

Fuses are a tricky thing to spec correctly and you can't assume that because the wire can handle 10A and the fuse is 10A that a fault hasn't damaged anything. The amount of time a fuse will take to blow varies greatly with temperature and current and doesn't always behave the same way a loomed wire will. A 20A fuse won't be guaranteed to blow until 40A, at 30A it may be fine. A 10A rated circuit with a high-impedance short (like a loose wire-to-chassis short) on a discharged battery could easily max out at 30A. A discharged motorcycle battery with 30A coming out of it will probably be at 8V or so, so your total resistance only needs to be in the area of 300mR. With a few connectors (the fuse terminals for instance) and the wire itself, 100-200mR isn't impossible as a starting point.

The problem is, you're relying on a fuse that is being used in its least linear, least reliable, least predictable mode.

Edit: By the way, sounds like you should have taken me up on that offer of investing in my friends wrecked across...

[Danae]

Arguing with an engineer is a lot like wrestling in the mud with a pig. After a few hours, you realize that he likes it.

[Real_Wolf]

Arguing with an engineer is a lot like wrestling in the mud with a pig. After a few hours, you realize that he likes it.

Lol, yeah, but I enjoy arguments too (drives so many people I know nuts)

man the thread title sure is fitting isn't it?

before I begin, it's good wade conceeds that putting a 20A fuse in place of a blown 10A is a stupid idea. It's a good thing that's not what he did, buut in the future he should really be more specific about what he's doing or we can't really help diagnose anything.....



In almost a decade of mucking with motorcycles I have never seen a "controlled" case. You have an electrical fault, indicated by starting issues and dead fuses, and have no idea what's the cause of it. How can you be certain that doubling the rating on even a seemingly unrelated circuit is a safe move?

remember that the heat loss is proportional to the square of the current, so a 20A fuse will allow four times the energy to heat up your wiring loom before it begins to fail, and that failure is going to take time which can be on the order of seconds. A short burst of current actually has a good chance of leaving the fuse intact as the "heat" is on for such a brief period that the fuse doesn't have enough time to melt. I've got a few 15A headlight fuses where the plastic got hot enough to melt before the fuse wire finally gave up, after a sustained, heavy load.

When your 10A fuse blew it could have been from a short due to wear on wiring insulation. This is a very common thing to find on bikes, and was present on that aforementioned headlight circuit which experiences no movement and is much younger than your own. It could be that your 20A circuit is also worn, or any heat damage from the 10A blowing has now created a fault in that 20A circuit.

Putting in a 20A is going to cause heating in the wires long before it blows, (remember they all tend to go down the one bundle wrapped in plastic and tape) possibly causing other wires to short. Would you like a quote on buying and installing a new wiring loom, too?

So next time you go about swapping fuses, do consider that unless you've thoroughly inspected the entire wiring loom for defects, and then checked all electronics for similar faults, this is no "controlled" case you speak of - and by that point you should know what's wrong anyway


I know a damn bit more about automotive electrics than you might realise, and could not only build but improve on some of the older electronic systems our bikes are running - this isn't radio/microwave frequency stuff where I'm happy to admit I have little knowledge.

running a 20A fuse in a 10A circuit, especially when there is an unknown electrical fault, is a stupid idea and I don't care how highly qualified you might think you are.



fair enough, get the forks done if mum's paying but good luck getting a mechanic to admit they've fucked up.



$70 an hour. Is it really worth the time saving to have the mechanic playing diagnostic and do you really expect them to waste time doing a thorough search for cheap parts?

On the rare occasion I do get a mechanic to work on my bike(s), I know he has already done the same job successfully to another bike of the same model/type (so he won't waste hours learning on the spot how to, say, access my carbs), and I will know the cost of or supply the parts myself.

Yeah, but if the current flowing through that circuit is non-existent, due to the knowledge that the battery does not have a short accross its terminals, and that each circuit, without starter motor being run or engine on, runs with the 10A fine (changing the 2 good ones between the 3 spots), and only putting it in to see if it is effecting something, its alot more 'controlled' than just sticking it in, taking no precautions like checking on things, etc. Controlled case doesn't mean every variable is accounted for, it means its done to the best of the potential at the time.

As for the mechanic, its going to a guy who I know has done Dare's fork seal, and the similarities between my gsx and the gsf are alot greater than the differences (we do have the same forks from googling it).

Edit: By the way, sounds like you should have taken me up on that offer of investing in my friends wrecked across...

Woulda loved to buy that, but didn't get in contact with you + didn't have much money. If you know of another one thats still available I'd be interested but not sure when funds would be available

[Squiggles]

I suggest you spend at least a 3rd of the bikes value at the mechanics and put away 20% of its value each year to cover the costs of keeping it running right. You've failed epically to get this thing sorted nice and proper when it was cheap to do so and it'll be expensive now (Before we knew something about the cause of its problems, now it could be absolutely anything). I'd say dont make the same mistake again but i think it'll fall on deaf ears.

[jono035]

It was a dodgy thing to do, but ultimately a judgement call. It didn't turn out badly so I suggest live and learn. If you're worried, buy some household fuse wire. Fuse wire can be safely paralleled up.

Yeah, I assume it's still parked somewhere up north. Not much use to me now that I no longer have one.

Also, I don't think the fork seals are what people are referring to when they say get a good mechanic...