Blowing Rectifiers Please Help

[BIG E]

Bike is a bobber project. i know how some of you feel but i actually saved this bike from the scrapyard so in a way i still saved one. it is hardtailed and welded with a springer seat. original carbs cleaned and rejetted the mains. pod filters, drag exhaust. the rest is stock. All the lighting has been removed and the fuses in the fuse box are currently pulled. the fuse block has only the ignition and main fuses in. The rest of the wiring harness is in a fake oil tank where the stock airbox used to be. I was jumping the bike from a jump box and had a battery that was to big rigged up and i was riding it around like that. No serious riding just around the block. All the problems started when i put the cdi and fuse box etc... in the fake oil tank. The fuse box was taken apart and put back together correctly once the wires were ran. Started the bike up and smelled a god awful burning, and then the rectifier billowed smoke. I did not have the ground from the motor to the frame, or a battery, or any lights on the bike. At first i thought the rectifier was pulling all the ground for the bike and got hot and melted. Got another rectifier, hooked up the motor to frame ground drove around the block a couple times, again with no battery. It was fine and ran like a raped date after the rejetting. Went and got new plugs, put new plugs in and took it 1/4 of a mile and it again ran better until it died. I smelled the blown rectifier again got towed back by the 4wheeler tried to start it with the jump box and it billowed smoke. Ive stared at the wiring schematic, looked for shorts, checked the grounds and still cant figure it out. What should i look for? will not running the battery melt the rectifier? Im only running a headlight and taillight(which arent currently installed) would lack of lighting cause the rectifier to over heat because its under worked and building it up? im lost i dont know much about these bikes but i can just about fix anything but electric. Any ideas or tips or anything electrical i can remove to make tracing it easier.

[ManagerMike]

Running without a battery could very well be the issue, severe electrical mods notwithstanding, the voltage regulator requires the battery in the circuit to act not as just a storage unit, but as a voltage reference and as a buffer (for lack of any better non high tech adjectives) so it can control the field of the alternator to achieve proper charging voltage.
Without a battery, the alternator is usually 'full field' and outputting near 18volts which can sound the death knoll for most rectifiers, lamps, ignition modules and so on.

Recommend a battery. Good luck.

[crazy steve]

Yep, not having a battery is the problem. Alternators are not self-exciting like a generator; that's the reason you can push-start a generator equipped vehicle with a dead-flat battery, but not one with an alternator. Lose the external voltage source by removing the battery after starting, and the system will go to full output trying to 'charge' the non-existant battery.

Kills the diodes every time...

[natemoen]

Agree with these two. I have done it with other vehicles

[Larrym]

Battery MIA???

BIG E,

Thank you for being considerate of "our" sensitivities regarding <ahem...> certain "modifications" made to an XS/XJ. Me? I say that if you kept one of these bikes from sliding into the smelter to be reincarnated as a PRIUS then you have my heartfelt support. Like a phoenix reborn the bike may "reinvent" itself. All I care about is that the effort is made to STOP or delay that inevitable date with the bike crusher instead of taking actions on a path directly towards it.

Now as far as those rectifiers going bad and letting the magic smoke out?? Well, take a look at this thread here on the Channel 11 forum:

http://www.xs11.com/forum/showthread.php?t=27686

Be sure to click on the link that takes you to the UK site and the simplified wiring diagrams. A little far down the page is the simplest one I'd endorse made by XS1100Chop.

(Love those UK dudes: Brilliant!!)

You'll find that indeed, at the very simplest and bare bones functioning level that the electrical system does require a battery properly located and connected.

It is clear to me that your "presenting problem" is in fact directly related to the absence of that necessary battery.

Please use the schematic diagram as a guide in your future efforts to keep your bike out there on the road and as far away from the smelter smoke as possible.

[BIG E]

it seems it did this not all at once but progressivley so my first thought was with no battery the voltage regulator would put everything in over drive like you guys are saying but wouldn't the jump box act as a battery most of the time it ran with that but then I'd take it for a spin without slowly killing the rectifier I guess. what years will fit my bike so when I look on ebay I can grab one. Mine is a 78 standard I beleive

[DGXSER]

Since the engine and electrical charging system are the same on all but the XJ models, you should be able to get one from any model and any year XS1100. The XJ might work, but I am not certain.

[Larrym]

Lead Plates and Shipping Costs...

The battery for all XS's are 12 volt 20 Amp per the "factory manual".

You're looking at something like this:


(Courtesy of yuasaBatteries.com)

For more details like the physical dimensions go here:

http://www.yuasabatteries.com/motorc...ing#formanchor

Me? I found out that while the internet may offer batteries for "cheep" they get you on the shipping. (Lead is heavy, right?)

I just go to my "regular" auto/bike parts store. Just lazy I guess...

[natemoen]

Heck you can get a battery from wal mart for 30 bucks.

[Larrym]

Double The Fun!!

Heck you can get a battery from wal mart for 30 bucks.

And play Bingo while at the Store too:



Good one Nate. Win/Win scenario all 'round!

[DiverRay]

You can use almost ANY 12 Volt battery. If you want, just pick up a small one to hide in the "oil" box. As long as you use a kick starter, the battery just needs to keep the charging at a reasonable level, and supply the 12V. for the TCI on startup. I would buy a new rectifier from geezer, at http://www.oregonmotorcycleparts.com/. Parts are WELL built, and work well. I've got one on my '79 that's for sale.
Also, do go with the "basic" wire diagram from the UK. I think they have a good set-up for a "minimal" bike configuration.

[BIG E]

i know the importaqnce of a battery fellas but im used to dirtbikes with stators. i didnt think that the xs1100 needed the battery until i fried the rectifiers and that was my only thought after i checked all the grounds connectors, and shorts etc... i had the oem size battery in it but after the hardtail i needed a smaller one to fit under the seat in a battery box i made found one that was the right dimensions and it will be here tuesday only spen 50 bux on it and its 200cca which should handle the bike no problem. i just need a rectifier and wait on the battery to be hooked up and then start it. the rectifier is ground, there is a ground from the engine to the frame, and from the battery to the frame, and the starter button switch on the handlebar is ground. is there any im missing???

[skids]

the rectifier is ground, there is a ground from the engine to the frame, and from the battery to the frame, and the starter button switch on the handlebar is ground. is there any im missing???

It seems like you will have the bases covered once the battery in.

Make sure all of those connections are clean, especially where the VR mounts because it needs good ground there and the frame is typically painted!