battery wire getting super hot when ignition is turned on....

Scrappy

Scrappy

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Heya folks, i am new to this forum (forums in general) so here goes. I am in the process of finishing up my first Bobber project and have come to a brick wall. This a 78/79 xs650 (the frame tag says 9/78 so not sure what model year that counts as) and i have it set up for kick only. wiring has been kept minimalist: regulator, rectifier, stator, and a headlight/tail light circuit. I am using the TC Bros chopper wiring. if your not familiar it uses the stock connections for the above mentioned components runs the red wire out of the rectifier thru a 20 amp to the battery, runs a black outta the rec. to the neg. on the battery and runs a brown to the switched side of the ignition. on the switched side are also the 12v that runs to the condenser, points and the coils. The stator has had the nylon screws installed, battery is grounded with 8g to the frame. my battery wire is getting super hot and popping fuses if not melting them apart. I have changed out the rectifier and condenser with new ones from MikesXS, swapped out the stator, swapped out the regulator, ohmed the coils (right around 4 +-.2ohms)....bike isnt starting, and like i said that + lead is gettin spicy. What am I missin here fellas?
 
Split apart all the wires coming out of the ignition switch hook them up one at a time when the fuse blows that's the wire that has a short to ground somewhere trace it till you find the problem. A recent bobber builder found that a wire connection shorted on his "oil tank" cover when it was closed.
 
Thanks Gary, so i am just using a push button switch that has two leads coming out iof it, one hot the other switched. The type of switch that you hit once and things go hot, and again and things are off. Does that change anything?
 
It shouldn't, but; Is it rated for the load you have put on it? Always possible the switch itself is faulty shorted or doesn't function the way you would expect it to I guess.
 
Well I hate to randomly throw part$ at problems so I'd probably go dig a household light switch out of my junk box and use it replace the switch, see if it's the problem? Eliminate one possibility at a time. Somewhere around a 20 amp DC rated switch should be adequate. Most switches have their rating stamped on the case somewhere.
 
Take the TC Bros pos off send it back, tell them it's crap and build one out your old stock harness.
While your building your own harness you might even learn something.
One the build date on the frame. The build year is from September 1 to August 31. As in Sept 1 of 78 to Aug 31 of 79 are 79's. Your bike was built in September 78, that makes it a 79.
Leo
 
thanks Leo bout the make info, on the harness, cut down the stock harness to the basic components that the tc bros one ends up using. However the stator wires and connector ended up being junk, and i was having other wires heating up, so thats why i am using the one from TC Bros, and in the process replaced every component along the way....
 
you can use your ohms meter to check for grounds before you take it all apart also. going from bat. - side to what ever should not be grounded. disconnect your + side of battery before you do....
 
I had the exact same problem.
Melting fuse on + lead from battery.
Your wire from the battery is not passing full current.
Your post states that you are using the separate regulator and rectifier with points.
Yet your stator has nylon screws installed.
I dont think you need the nylon screws.
These are only for upgrading to the newer solid state rectifier/regulator combos or if you are building pamco petes chrysler/ radio shack combo.
Use regular screws and give it a try.
 
Hey fellas, I appreciate all the info and things to look for. In doing some outside research, I also found that the rotor should ohm out between 5 and 7 ohms....mine jumps from 3 to 18, if i read this right, that is my issue. Thankfully I have a parts bike, and that rotor ohms out at 5.5. I did some isolation by pressing my ignition button to the ON position, found that everything was good til I hooked up the stator. ONTHEROCKS, i went ahead and grounded the brush assembly agian, but I think with that bad rotor, thats trumping everything else. I am going to replace the rotor with the good one frm my parts bike sometime this coming week, and get back you you guys.
 
yup yup, got the rotor puller on order from a local shop here, so i spose i will work on cleanin up the mess i made of everything else while trouble shootin this issue...
 
So it ended up being the bad rotor, shorting to ground, causing the battery wire to get really hot and slowly blowing the fuse. Got to rotor pulled off my 78 and installed on my 79 and all is good....as far as that issue....and I got to take my bobber around the block a few times after getting it started for the first time and adjusting my carbs.
 

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