Help needed - CBR 600 wont start
in [Tech]
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From: paul c on 18 May 2010 12:21 pokee joe wrote: > paul c <toledobythesea(a)oohay.ac> wrote in > news:PfoIn.4411$z%6.4398(a)edtnps83: > >> A lesson I've re-learned a number of times on bikes and cars: Even >> a little six-inch ground strap when the ends are corroded/oxydized >> or even thinned due to use might have as much as a quarter-ohm >> resistance. A 300 watt starter motor has a resistance of less than >> half an ohm. In that case, a 12 V battery would lose a third of >> its voltage, ie., 4 V on the ground strap, leaving only 8 V max for >> the starter. > > Actually, it's a lot worse than that. Even small starter motors will > draw a locked rotor current of 100 amps or more. That means the > resistance of the starter windings is around .1 ohms and it's not > unusual for larger two cylinder engines to have starters that have > less than .04 ohms. Your 300 watt starter will draw more than 150 amps > initially and have a resistance of less than .075 ohms. That's why we > require starting batteries in the first place, they are specifically > made to provide far higher short term current than deep cycle > batteries. > ... Nice points. Makes sense that the initial huge current and the steady current would bypass the main fuse. Straying a little, I noticed the wiring diagram for a little S65 at http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php#class shows negative ground and the main fuse is on the negative side, unlike most others I've seen where the fuse is on the positive side of the battery. Not sure why this was done.
From: paul c on 18 May 2010 12:43 pokee joe wrote: > "`" <breoganmacbrath(a)yahoo.com> wrote in news:dd933f7b-a5e1-43ac-bf6f- > 0d011b8f95bd(a)u3g2000prl.googlegroups.com: > >> In the case of jump starting a motorcycle with a discharged battery >> from a car with the engine running, the zener diode in a motorcycle >> equipped with a permanent magnet alternator and a fully functioning >> shunt type regulator would "see" up to 15 or 16 VDC, because the two >> batteries are connected in >> parallel. >> > > Only if the jumper cables are awg 000 or larger. Even then, you would > need some other kind of connectors than the spring clamps normally > seen on jumper cables. > > What actually happens is, the discharged motorcycle battery draws 50 > amps or so, resulting in a voltage drop in the jumper cables and > clamps, so the actual voltage the motorcycle harness sees is only > about 13 volts, at most. As long as the motorcycle battery is drawing > a heavy current through the jumper cables, the motorcycle's electrical > system is protected by the battery, just as car batteries used to be > used as voltage regulators and filters for power supplies, back before > the days of electrolytic capacitors and electronic voltage regulators. > > If the problem is misdiagnosed as a discharged battery on the > motorcycle and the motorcycle battery is actually charged, then you > can have a serious problem. > > regards, > Joe Why is it that many people assume the car engine must be running when jump-starting a bike (assuming the bike is in good enough shape to start promptly)?
From: S'mee on 18 May 2010 14:38 On May 18, 10:43 am, paul c <toledobythe...(a)oohay.ac> wrote: > pokee joe wrote: > > "`" <breoganmacbr...(a)yahoo.com> wrote in news:dd933f7b-a5e1-43ac-bf6f- > > 0d011b8f9...(a)u3g2000prl.googlegroups.com: > > >> In the case of jump starting a motorcycle with a discharged battery > >> from a car with the engine running, the zener diode in a motorcycle > >> equipped with a permanent magnet alternator and a fully functioning > >> shunt type regulator would "see" up to 15 or 16 VDC, because the two > >> batteries are connected in > >> parallel. > > > Only if the jumper cables are awg 000 or larger. Even then, you would > > need some other kind of connectors than the spring clamps normally > > seen on jumper cables. > > > What actually happens is, the discharged motorcycle battery draws 50 > > amps or so, resulting in a voltage drop in the jumper cables and > > clamps, so the actual voltage the motorcycle harness sees is only > > about 13 volts, at most. As long as the motorcycle battery is drawing > > a heavy current through the jumper cables, the motorcycle's electrical > > system is protected by the battery, just as car batteries used to be > > used as voltage regulators and filters for power supplies, back before > > the days of electrolytic capacitors and electronic voltage regulators. > > > If the problem is misdiagnosed as a discharged battery on the > > motorcycle and the motorcycle battery is actually charged, then you > > can have a serious problem. > > > regards, > > Joe > > Why is it that many people assume the car engine must be running when > jump-starting a bike (assuming the bike is in good enough shape to start > promptly)? Got me! The old man taught me the right way to do it decades ago. Car OFF, cables hooked up properly (did you remember to clean the terminals AND the clips?) start motorcycle and yes I've seen a kick start motorcycle with a battery so flat we had to jump it so it could be started. After that it had no problems...still not sure WHY the battery was so flat.
From: pokee joe on 18 May 2010 20:55 paul c <toledobythesea(a)oohay.ac> wrote in news:itzIn.4173$Z6.2499(a)edtnps82: > Why is it that many people assume the car engine must be running > when jump-starting a bike (assuming the bike is in good enough > shape to start promptly)? > Why? Oh goody, now we get to wander off into philosophy :-) People assume things simply because they lack comprehension. In other words, they are ignorant. When you know how something works, you have no need for assumptions. Assumptions are always made from ignorance and are always flawed in some way. Modern shaman pretend they can explain why people think the way they do. Since I can't read other people's thoughts, I don't even know WHAT someone else thinks, let alone WHY they think it. regards, Joe
From: ` on 18 May 2010 21:43
On May 18, 5:55 pm, pokee joe <nos...(a)dont.bother.gov> wrote: > Modern shaman pretend they can explain why people think the way they do. > Since I can't read other people's thoughts, I don't even know WHAT > someone else thinks, let alone WHY they think it. http://www.himalayanacademy.com/resources/images/Gurudeva-photo.jpg Gurudeva wasn't pretending. He *knew* what makes people tick... |