CB125 coil problem

[wbks]

On my cb125 (which I just started for the first time) I have just hooked up a 12v battery for the total loss system. The coil is a 6v one. After maybe 5 mins max of going up and down the road at no more than 1/4 throttle i stopped the engine to notice there was something sizzling and burning from the coil and some liquid leaked out onto the head then turned into this white wax like substance. In case you didn't guess I've never tampered with electronics. Can anyone tell me what's wrong? Is the coil suposed to be 12v to match the battery? Are the connections wrong some how?

[craisin]

well you will need a ballast resistor so the coil doesnt over heat and the points dont get burnt. I had a yb yamaha a while ago and it would do hot starts it had points and a 12 volt coil
I had a bosch GT40 coil that i hooked with a ballast resistor that i put in a cut up litre oil container so it wouldnt get wet and open at the bottom so hot air could get out. Threw a massive spark I used a condensor out of a jar car that had a ballasted point ignition. increased reliability imensely

[Ixion]

Coild overheating. They come in 12V and 6V (24V too, atcually). No electronics there, just a simple points system. Throttle is irrelevant. Almost impossible to get the connections wrong , and if you did it wouldn't start.

Wire from battery to switch. From switch to coil. Other side of coil to points. Condensor across the points. Bob's y' uncle.

Try a good correct voltage coil .

I do so love nice simple systems.

[craisin]

Coild overheating. They come in 12V and 6V (24V too, atcually). No electronics there, just a simple points system. Throttle is irrelevant. Almost impossible to get the connections wrong , and if you did it wouldn't start.

Wire from battery to switch. From switch to coil. Other side of coil to points. Condensor across the points. Bob's y' uncle.

Try a good correct voltage coil .

I do so love nice simple systems.

how i saw it was he put a 12 volt battery in a six volt system so the points and condensor are made for six volts. using car coils on bikes for racing is an old trick and by doing so the point last longer. And you do need to still be running at the end of the race. As most of those hondas have the points on the cylinder head which is the hottest part of the engine so the heel of the cam wears down quick and the bike gets out of tune quick. Old points systems have too feeble spark for modern fuel, CDIs are better smart guys find them simple.and they dont need a battery that saves weight. Well I assume its his bucket racer

[gixxer-king]

pretty sure (by the sounds) theres a 6v coil on a 12v system. maybe the resistor has broken down or otherwise failed?

[gixxer-king]

sorry poster one. continuing on, sounds like resistor may have failed and that has let 12v through to cook the coil. liquid equals coil is cooked so its a matter of finding why/

[craisin]

thats funny when most resistors fail the let no volts thruhey I will be 60 this year when I was young I used to fix my old mans sidevalve V8 so Im used of working with points. I guess if one of you guys wired something up wrong you may be shy to admit it. Hey we all phuck things up thats how we learn. Like if you just twist 2 wires together to join them sooner or later you will get bad conections so its best to solder them that way your not fixing it on race day when the engine is hot

[DEATH_INC.]

It's simple, he said it himself......12v battery/6v coil.....never gonna last! I'm pretty sure the ballast coils are around 9v (not 6) too, so a car ballast won't work either. Run a 12v coil, problem solved

[Motu]

Car ballast coils are 6 volt (listed as 12volt ballast,6 volt non ballast),but they could be too big for a bike system.The condenser will work 6 or 12 volts.Do you want to keep it the stock 6 volts or convert to 12 volt? Either way you will need another coil.

[wbks]

Sully60 is sending me a 12v and a 6v coil for free. Chur man! Just before I go screwing up any more coils. There are only wires from the battery to the points and the coil, nothing else, so I won't need any thing apart from the 6v coil to run it with a 6v battery? 'Cause I just bought one 6v battery. Its weird cause the bike was still running with the shit coming out of the coil but this morning when i tried to start it, it didn't even sound like it was sparking. But motu- I am probably going to put in a new 6v coil to match the new 6v battery. I could do the 12 setup to get a slightly better spark (or so I'm assuming) but it would wear out the points a lot faster according to Xion so I figure a good reliable bike is better then a slightly better running one that needs new points every month.

[Ixion]

A wire from the battery to the points ? That would be unusual (though not impossible). The classic wiring is battery : one wire to earth, one wire to a switch . From the switch a wire to one of the LT connections of the coil. Other side of the coil, a wire to the points.Other side of points is earth (to the engine) . Condensor sits across the points.

It's not rocket science or strnage. Shit loads of vehicles around still have points ignition. Five of them in my gargre alone.

And the 12V 6V is easy. Just make everything the same. Anything with a voltage stamped on it, all either 6v or 12v .

EDIT I never said 12 volts would wear out the points in a month. Couple of years , maybe.

[craisin]

hey Ixion I thought the young fella was going to go bucket racing. Wasnt intending to run down the contents of your garage. Anyway have a good weekend

[wbks]

Yea it is a bucket. I appreciate any tips or advice though

[craisin]

well the car ballast and GT40 coil worked on my 2 stroke Yamaha just had to cover the ballast to keep the weather out. I think you are doing the right thing with the 6 volt coil and 6 volt battery=less things to go wrong. If you set-up your bike with simple things that you understand you dont have to be reliant on other to fix it as you understand it. Ifanbody offers you a TAC or Trasistor assisted contacts grab it if its free. Its a little box that hooks up to the points and coil but you have to mount it away from the heat of the exhaust. google it it may also be known as a Darlington Pair. Anyway just get it running for now and do more improvement come winter time.

[Backmarker]

The principle behind ballast coils is to run a coil of lower voltage than the operating system ie 6-9v for a twelve volt system. The ballast resistor is basically a coil of high tensile wire designed to heat up with the amperage running through it and the increased resistance of this lowers the voltage.

What this means is you have a 6v coil 'doubling' its output when the ignition is first switched/engine started which is when you need your best HT ouput and then once things warm up the coil supply voltage drops to match the coils normal running voltage.

The windings are oil cooled, that is the liquid you saw coming out. Points life are not shortened, they are still running on their intended voltage.

Hope this helps

Cheers