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Post by Diego the toe clipper on Jun 25, 2019 9:06:16 GMT
My bike has started cutting out after about 40 minutes of constant riding. It is fine all the time up to when it first splutters and dies, then it just keeps doing it more and more frequently. The rev counter dies electrically, and the dash shows a Chec message which is the same as when you hit the kill switch, so effectively the ignition circuit is losing power. No fault codes, just power loss like a switch.
I have spent a lot of time checking switches and wiring over the last few weeks, and have finally narrowed it down to quite a specific area.
When the bike dies, it often just comes back to life on its own in a matter of seconds, but on the odd occasion that it stays dead and I get the chance to stop and investigate, I can get the ignition circuit to come back to life (fuel pump primes and the Chec message goes away on the dash) by wiggling the wires that go into the fuse box.
The fuse box is hard wired into the main loom, and all the connectors are good and strong and firmly in place, so the fuses are sitting and connecting OK, there is no corrosion at all. So I think it must be a break in one of the wires going to the ignition fuse, but I'm shitting myself about cutting into the loom.
How can I find out which wire it is? I can't recreate the fault by tugging on the wires individually, and obviously on a tester when the bike is stopped all the wiring tests OK for continuity... Should I cut all the wires and extend the loom with new wires on every one?
Anyone got any good ideas / suggestions before I go hacking into my loom?
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Post by Droog on Jun 26, 2019 16:28:55 GMT
Couple of questions:
What bike is it?
How old is it?
How much is a replacement loom new or second-hand should it require one?
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Post by Diego the toe clipper on Jun 27, 2019 8:56:07 GMT
GSXR 750 K5 (2005), over 70,000 kms
Second hand looms available form about 100€, but let's be honest, the chances that they are unmolested are slim to none. Most have been spliced to incorporate alarms at some point, so this is the last resort.
To kind of answer my own Q, I got one of those mini digital voltmeters off Amazon yesterday and I'm going to wire in in the the suspect fuse terminal and mount it on the dash so that I can see if voltage is being lost at any one point when the power failure happens.
My theory is that if I keep moving the voltage sensor along the circuit away from the fuse box, I will eventually find out with a reasonable degree of accuracy, where the "break" or fault is.
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Post by neilf on Jun 27, 2019 13:15:18 GMT
My K5 has just done 30K miles, but the engine has only done 24K as I had to change it last year after I lost 6th gear. It was going to cost the same to strip and replace parts as it was to fit another engine with a lower mileage... a no brainer really.
Last year, when riding through France, my allegedly deactivated Datatool developed a terminal fault which immobilised the engine as I was riding it. The alarm had to be stripped out and the loom re-wired; so I can understand your reluctance to buy a secondhand one. mine was done professionally and meticulously tested one wire at a time.
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Post by Diego the toe clipper on Jun 27, 2019 14:44:16 GMT
Fortunately I am able to perform most repairs on my own, the cost is my time, but I just don't trust anyone else to work on my bikes. Even when special tools are involved, buying them / making them is usually cheaper than paying a shop's time.
As an example, I recently changed my fork seals including swapping one of the inner forks legs, and on stripping the forks I noticed that one had more components that the other. The last people to change the seals had simply left out one of the spacers... I was given the receipt for that last seal change when I bought the bike, so it was done by a "proper" workshop.
If I have to change the loom, I will do it myself (not that I fancy it much TBH) but I think I'll draw the line at buying brand new. The bike is probably worth quite a bit in parts, so I'd just break it and sell it.
But all that seem excessive for what seems to be a break in one wire.
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Post by neilf on Jun 27, 2019 15:29:33 GMT
Unfortunately, I was stuck in the middle of France without access to tools or the time required to do the job. My K5 hasn't missed a beat or failed to start. When i got home, I stripped of the fairings and the job that the bike shop did certainly looks professional.
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Post by Droog on Jun 27, 2019 20:26:45 GMT
GSXR 750 K5 (2005), over 70,000 kms Second hand looms available form about 100€, but let's be honest, the chances that they are unmolested are slim to none. Most have been spliced to incorporate alarms at some point, so this is the last resort. To kind of answer my own Q, I got one of those mini digital voltmeters off Amazon yesterday and I'm going to wire in in the the suspect fuse terminal and mount it on the dash so that I can see if voltage is being lost at any one point when the power failure happens. My theory is that if I keep moving the voltage sensor along the circuit away from the fuse box, I will eventually find out with a reasonable degree of accuracy, where the "break" or fault is. This is a good plan. Keep me informed. |
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Post by mekon on Jun 27, 2019 21:20:56 GMT
This is the problem with more modern stuff. Great when it works, nightmare when it doesn't. When I read a thread about a problem I was having with my Audi some bloke had taken his to dealer and after great expense even they had no idea how to fix it. He may as well just replace the engine.
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Post by Diego the toe clipper on Jun 28, 2019 7:11:49 GMT
Update.
So I started looking yesterday at how to best temporarily splice in the voltmeter close to the fuse box.
I tried again to pull on each of the suspect wires individually to try to provoke the failure, but I couldn't get it do it.
So it occurred to me that, even though I had swapped the 15A ignition circuit fuse, I had swapped it with the original spare 15A fuse from the fuse box. So, thinking that I may be the most unlucky person in the world and have two defective fuses, I put in a new one, brand new.
Then I went out for a ride with a multimeter under the seat to check things when it failed. It is stupid hot here at the moment, 40º+, and the roads were clear so I got in some fast twisties and some even faster motorway. For 1 hour, non-stop. I even let the bike idle for a while at a stand-still to get the fan to kick in to make sure that all the components reached their peak temperature. No failure...
Not sure if I really have fixed it, or how to test the "duff" fuses, I'm thinking of heating them up in a pan of water to test continuity at high temp.
Will report back!
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Post by neilf on Jun 28, 2019 8:38:26 GMT
I've never heard of this before, but it could be that there is a hairline crack in the fuse and when the metal expands due to the heat, the crack gets large enough for gap to appear!
Just speculation on my part!
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Post by Diego the toe clipper on Jun 28, 2019 12:01:38 GMT
Yeah, I can't really explain it either. On one hand I can sort of see how a fuse, which is by design the weakest part of a circuit, could be damaged by high vibrations and repeated heat cycles, even it it isn't blown by excess current.
But, on the other hand, if the fuse is cracked, why would heat make the crack separate the metal? With heat metal expands which should "fill" the crack. Also, why would pushing the wiring upwards into the fuse box cause a defective fuse to make contact again without directly touching the fuse itself..
Curiouser and curiouser thought Alice...
Alice, Alice ? Who the fuck is Alice? wrote Roy Chubby Brown.
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Post by neilf on Jun 28, 2019 13:43:39 GMT
Again, speculation, but the fuse is in a plastic case which will expand/retract at different rates compared to metal!?
Thermal expansion is not my thing.
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Post by Diego the toe clipper on Jul 15, 2019 9:17:47 GMT
Update:
It wasn't the fuse.. It started to fail again last week (hottest day of the week, got up to about 40º).
So I installed my mini digital voltmeter to measure the voltage on the output side of the fuse, and sure enough it still shows 13V even when the ignition circuit is dead, so the fault is after the fuse box.
The circuit runs from the fuse through the relay commonly known as the indicator relay, but actually, that relay is also the interlock for the side stand switch, and it seems to be unstable. Sometimes even touching the relay causes the circuit to energise / fail. The connectors to the base of the relay are all in place, clean and tight.
I had some success getting the bike to run for a bit at the weekend by taking out the relay, smacking on the kerb and putting it back in. But in the end even that stopped working and I had to call a recovery truck to take the bike home.
Suzuki want 65€ for a new relay so I'm looking for a cheaper alternative to test my theory!
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Post by neilf on Jul 15, 2019 9:53:32 GMT
Ebay or a breakers!?
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Post by Diego the toe clipper on Jul 15, 2019 10:09:37 GMT
There's a lot of after-market units on offer with extra resistors on the indicator side to solve the fast flashing of LED indicators. These should have a "copy & paste" set up on the ignition circuit side. So I am looking at these, just need to find a shop in Madrid that stocks them. Better a new after-market unit than a used item which could also be dodgy I reckon. E-bay doesn't work well in Spain anyway, and paying international postage (and waiting two weeks for it to arrive) is not worth it for a 25 quid relay. I could always just bridge the wires of the relay on the ignition circuit side of the relay, but that means either hacking into the wiring under the fuse box, or leaving the relay out (no indicators) for a longish ride out, which I'm not too keen on TBH. |
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