Battery Box Refurb

The bike's been running great so that means it's time to go back and re-do a few minor details that didn't get finished to my satisfaction the first time around. I'm a bit of a perfectionist so I like to make sure everything's done just right.

One of those things was the battery box. It's kind of buried in the center of the bike so I didn't mess with it when I was working on the electrical system. It was pretty rusty, though, and I was worried that the sheet metal would crack and dump my battery out onto the swingarm.

I also wanted an excuse to get one of those non-vented AGM batteries they have now, so I sold the old battery to my friend Dan and ripped out the box.

It was rusty but not all the way through - A quick soak in my favorite Phosphoric Acid solution removed the rust and left it ready for sanding and paint. My preferred rustoleum hard-hat did it's usual good job, and I threw it in the oven for an hour at 175 degrees to get it rock hard.

Back in the bike no-one can see it, but I know it's there.

Finally Coming Together

With the petcock finished and the engine side covers polished, there isn't much left to do but ride this thing. I gave it a quick once-over, checked the air pressure and hit the road.

I visited a friend from the GS Resources to synchronize the carburetors. Thanks Ed! ON the road the new regulator works great - 13.8v at idle with the lights on, and a fully charged battery after 200 miles and sitting around all weekend.

With the carbs synced, the bike runs really well although I do notice the odd backfire and stumble. I may pull the carbs again soon to check them over, but only after I put some more miles on the bike to make sure it's not just "clearing it's throat". I'll also adjust the idle mixture screws a little too.

Other than that it's running perfectly. Being the perfectionist that I am, I might still play with a couple of small details. I don't have to, but I'd like to tweak the front suspension to perfection. I'm getting 65mm of front sag, which is about 30mm too many. And I'd like to maybe remove the passenger grab handle and plug the holes, but I haven't decided yet. In addition, the clutch cover seems to be oozing oil, but it's hard to tell because of the small amount.

Charging System

The bike seemed to charge OK, but the lights were dim at idle. They brightened up with a rev, which made be think that the stator and regulator were doing their job but the battery was weak.

At idle voltage was just 12 volts, but above 5,000 it climbed lethargically to 13.8. Within specs, but not very impressive. After a few days of charging the battery wouldn't give more than 12.2 volts, which is pretty low.

These bikes are known for having weak charging systems, though, so I wanted to head such problems off before they appear in the future, without spending a fortune. Since it was down for the engine work, I figured I'd do a little creative re-wiring.

The problems are many, but they come down to a marginal-sized stator, over-use (mis-use?) of bullet connectors, one stator phase (of three) that's completely unregulated and a regulator that's not efficiently grounded to the battery.

I formulated a plan to upgrade the weak spots of the stock system:

- Marginal stator: This I couldn't do much about - I measured the resistance of the stock one and it seemed fine. Looked fine too, when I pulled off the cover.

- Sub-optimal bullet connectors: I replaced all connectors with 1/4-inch spade terminals

- One unregulated stator phase: I replaced the separate rectifier and 2-phase regulator with a modern unit (from a Honda CBR929rr) that will control all three phases instead of just two. I wired the third phase directly to the regulator instead of through the lighting switch (and a bunch of bullet connectors).

- Poor rectifier/regulator wiring and design: I wired the regulator directly to battery instead of through the harness. The GS originally has a separate rectifier and regulator, which just adds resistance to the circuit. The 929 combined rectifier/regulator had two positive and two negative outputs - I ran one positive and one negative directly to the battery. The second positive went to the wiring harness like the stock regulator and the second negative was grounded to the starter solenoid along with the harness negative wire.

I took the opportunity to do some more cleaning of the battery box area. I also removed and painted the electrical panel for more bling. And finally, I replaced the weak battery with a nice new 12N14 battery from Wal Mart.

Now, even though the new regulator is about double the size of the old one, you can't tell. Looks good, doesn't it?

That should cure my electrical and charging problems for the forseeable future...