Melted Fuse.

[johnbirchjar]

Hi guys,had a first(I think) for me today,I was giving the old Classic a bit of a "pre-season" check over ,took the cover off the fuse box to discover the 25amp gen fuse had melted!! (I have allways been under the impression that fuses "blew" well before this sort of thing happen,) I have no idea how long the fuse has been in this condition,there have been none of the usual indications of "over charging" i.e. battery boiling dry,ultra bright lights,bulbs blowing,infact,everything normal,I have put a new fuse in and will keep an eye on it,oh, and I had to use pliers to get the old fuse out,any thoughts anyone?ride safe,J.B.

[Richard Negus]

Hi John,Sounds more like a poor connection at one or both ends of the fuse causing a high resistance and hence heat. It could also be underneatth the fuse holder where the wires have spade connectors. Same thing, corrosion and increased resistance.Is the fuse tight when you push it into place? If loose, that would give a poor contact too.R.

[spanner boy]

Basicaly poor connection equals high resistance equals heat. I would check all connectors including adjacent fuses. Also have a look at the wiring insulation and check for damage or signs of overheating ( hard wire or melted insulation )

[Dell Boy]

Hello John,I have had this. It was the yellow alternator wires overheating & burning up.Cheers,Derek.

[Richard Negus]

Derek,You're not alone!Most Commander owners have suffered this overheating at the a/c connector, caused I believe by high resistance in the terminals. Oddly, the F1 using the same generator/connectors/regulator doesn't suffer in the same way although both are delivering the same a/c output all the time. It could be that the F1 connectors are better protected from road salt and don't corrode so quickly. Or, they don't do the miles/the engines don't come out so often and the terminals don't lose their grip so soon I've tried various alternate connectors, and ended up thinking that soldering the wires together is the ultimate cure. However, once the wires have overheated, it seems very difficult to get solder to stickSee bodgerbloke's thread about endeavours on his Commander.R.

[johnbirchjar]

Hi guys,thanks for the tips,I have spent most of this afternoon looking for burnt or melted wires,checking connectors for corrosion & loose connections,(mostly around the fuse box area,)nothing looks untoward, should I be looking else where?Del Boy and Richard stated thees problems accure on Commanders,what about IP2's & Classics? am I right in thinking the electricary is different?ride safe,J,B.

[Dell Boy]

Hello John,I think the same alternator is used.Look for thick yellow wires coming from the behind the R/H big alloy plate. The connectors melt on these wires. Its a very long time since I have looked at an air cooled so I may not be very accurate with my information regarding locations.I solder mine together & fit connectors further down the line away from the alternator which has worked fine on mine.Good luck,Derek.

[Richard Negus]

John,The IP2/Classic has a smaller alternator than Commander and F1; only 180 watt and has longer a/c wires with individual Lucas bullet connectors directly to the Boyer regulator. I've never known these cables and connectors to overheat.Your problem is on the dc side of the system; have you checked battery voltage when the engine is running? The Boyer regulator is generally reliable, but it's possible yours is giving too high an output voltage. Battery voltage, engine running but everything elso OFF, shouldn't be more than about 14.8 volts. Usually, they don't normally show more than about 13.5 volts.R.

[johnbirchjar]

Thanks guys, I havn't got a voltmeeter? myself but I expect some of the guys that I meet at the pub most Saturdays will have one,I will make a few phone calls and hopefully one of them will bring one along. Most of us put vasaline on the battery terminals to prevent corrosion,has anyone tried doing the same to other electric points?e.g. wher the fuses fit in ect;Just a thought,ride safe,J.B.

[johnbirchjar]

Hi guys, I think I have a few problems rearing there ugly heads ,1st what do's the ballast resister do?I took it off the bike(to clean the terminals and make sure of bare metal contact) and it is in a sorry old state , the ceramic? body has crumbled away exposing metal,I have wraped insulating tape round it as a temperary bodge till I can buy a replacment (Boyers perhaps?) also a buddy of mine did a voltage test on the battery for the charge,and NOTHING!! ZILCH, not one amp/volt, nadda,was reaching the batery a check on the fuse and it seemed fine,I/we could take things no further as he knows even less about vehicle electrics than me!! The original Boyer VCR was replaced some 30 odd thousand miles ago with a Podronics? one from Graham. The next step will have to be a visit to someone who knows there way round bike electrics,I will report anon,ride safe,J.B.

[johnbirchjar]

Continuing on,I have re-examined the fuse box assembly and am of the oppinion that I will require one of those also,(the 25amp holder seem a bit of a loose fit compaired to the others) would these also be of Boyer manufacture?and having studied the worshop manual at length,I am beginning to make some sence of the electrics, and now know how to check the alternator output before the VCR(who's a clever boy then)don't laugh,vehicle electrics have allways been a bit of a black art to me ,I will report anon,ride safe,J.B.

[rustynuts]

1st what do's the ballast resister do?

As you probably know, when your starter is cranking, it draws such a large current that battery voltage drops to perhaps 8 Volts or so. This leads to a weak spark and can make starting difficult.A ballast resistor is sometimes used to overcome this. Instead of using a 12 Volt coil, a ballast resistor is connected in line with a 6 Volt coil. When the engine is running, the ballast resistor drops about 6 Volts giving the coil about 6 Volts so it runs happily. When you fire up your starter, the ballast resistor is bypassed and the full battery voltage (about 8 Volts) is connected directly to the 6 Volt coil, resulting in a good spark.The ballast resistor has a ceramic body because it gets bloody hot, so it isn't a good idea to wrap yours in PVC tape, as it is likely to go up in smoke!

[Dell Boy]

Hello John,I have a couple of ballast resistors or Trog probably has as well.They were fitted to Commando`s & early Ford Transits.Give me a ring.Derek F.