Hey guys, a newb to the forum. Looks like a great place.
Can you tell me if my 72 Bonneville has a negative or positive ground on the battery? Just got it and the battery was trashed so I replaced it. But, before wetting the new battery, I noticed the old battery was connected with the positive cable to the negative on the battery and want to be sure as to how the wiring is suppose to be before I wet the battery, turn it over and fry something.
If all the red wires go to the frame and also to the positive battery termainal. Beware most modern replacement battery's have the neg and pos were the battery has to go in termanials back not out facing you. I guess you got a fifty percent chance of blowing the fuse. Hope there is one. Stock place for a positive earth system fuse is the negitive side but because it dosen't mater watch out.
norbsa 1960 TR6 1963 Super Rocket 1965 650 Star 1966 441 1968 Thunderbolt 1969 Twinkle 250 1972 Fastback 1974 Roadster 1970 S.S Way too many BSA's not named http://decentcycles.com
Re: 72 Bonneville battery ground?#98217 08/11/062:26 am08/11/062:26 am
when i say a positive cable, i mean a red cable (from my experience on american stuff, red is positive) going to the negative on the battery. am i to understand that red wires on these bikes are negative?
What will a shop manual run me mailed to Macon. I see you're in Norcross.
Thanks TriJoe! Buster
Re: 72 Bonneville battery ground?#98220 08/11/064:28 am08/11/064:28 am
B, Try not to think "American Stuff" when working on English/Tri bikes. Another example is fuse size, that's another topic. Your bike (if stock) should be "positive ground", that's to say red wires connect to pos term (on battery) & connect to the frame/earth. Fifty-Fifty chance is way too high for me because of all the damage that can be done, when with just a small amount of checking - no chance, no damage. Email me.
Buster - Your bike came from the factory set up for "positive ground" which means that the Positive (+) terminal of the battery is connected to the frame of the machine. The original harness used RED wire to denote the positive, or ground, polarity. So on a stock bike with a stock harness, the RED wire is connected to the Positive (+) battery terminal.
If your bike has the stock Lucas rectifier or stock Lucas zener diode, then you MUST continue to use positive grounding.
However, a lot has happened in the last 30 years. New replacement electronic devices now on the market let you connect the bike up as the more common (but no better) negative ground. So it is up to you the owner/mechanic to determine how your particular motorcycle is polarized BEFORE you connect your battery, or parts of your charging system (and thereby your wallet) will suffer.
The quickest ways to do this (and I would certainly look for MORE than one of these to certify the polarity) is to 1) find the rectifier and observe its polarity, 2) find the zener (or other regulator) and observe its polarity, and 3) look at the ignition coils and see if the BLK/WHT and BLK/YEL (the points leads) are connected to plus or minus terminals.
If you do not understand what I am telling you, then it would be well worth your time to make the trip to our shop in Winder, GA to have it checked out before you install the battery. Give us a call at 770-867-1676, 9-9EST. And yes, of course we’re open 7 days a week.
BTW... the advice to charge your battery for 24 hours prior to installation is excellent. However, I would choose a much lower charge rate of something like 1/2A unless you sit the battery in a huge pot of water to absorb the excess heat.
It's not the color of the insulation that matters, it's where the conductors are connected that will determine whether you see smoke or not.
Case in point, we have a regular customer with a 1971 BSA A65L. The bike is completely stock and could be a concours winner except for one small detail. His entire wiring harness is made from RED wire. It's a beautiful job complete with heat shrink and all soldered joints. It's a triple pain to troubleshoot, but every wire, whether positive, negative or AC is RED.
I think the more prudent position to take is to assume that in the intervening 35 years that the bike HAS been modified. Your job Buster, is to determine to what extent.
Well, I got it runnin' with the help of RF Watley and his side kick Beano (sorry if spelling is wrong) on the phone. With the phone help, I ended up trying each wire with an OHM meter, and the green wire showed circuit to the frame, so I put it on the Pos. Batt terminal tickled the carb and the damn thing cranked on the first kick, even after sitting up for over 2 years. My luck ain't ever that good.
Anyhow, BIG THANKS to RF and Beano for taking time from work to give somebody free help on the phone, and also to the other people who responded here.
Now I've got a transmission question, but I'll start a new thread.