Yamaha XT550 regulator

[FilthyLuka]

Is there a website with their specs etc on it? can't find the fucker

Its the battery outta a GN250, i know cause i have a spare one and its pretty small

Your not running anything massive, so go into a dealer and ask about a battery for a little electric start dirtbike, that will work. If they aint got one, pull the battery used for a GN125, smaller still.

As far as specs go, as long as its 12v i wouldn't worry. You don't need to crank a starter motor so don't worry.

[xwhatsit]

Oi Wired1, my CB250RS is running a Big Fuck Off electrolytic cap in place of a battery. It's quite happily been running for tens of thousands of kilometres like that. I did have a problem when, after the headlight blew (just vibration and old age), all the other bulbs followed within 10km. However, as long as the headlight is on (and working), the electrics are about as reliable as one can expect. And no getting a sore leg trying to kickstart a bike on a cold morning with a flat battery!

I've got a few spare CB250RS reg/recs, do you want one? They're large and well-finned. Also used in the CX500 and various other quality Honda motorcycles Can't kill the bastards, people buy old ones from wreckers and fit them to modern bikes. Also have a spare Big Fuck Off cap -- Surplustronics on Queen St is heaven -- want it as well?

[FilthyLuka]

Oi Wired1, my CB250RS is running a Big Fuck Off electrolytic cap in place of a battery. It's quite happily been running for tens of thousands of kilometres like that. I did have a problem when, after the headlight blew (just vibration and old age), all the other bulbs followed within 10km. However, as long as the headlight is on (and working), the electrics are about as reliable as one can expect. And no getting a sore leg trying to kickstart a bike on a cold morning with a flat battery!

I've got a few spare CB250RS reg/recs, do you want one? They're large and well-finned. Also used in the CX500 and various other quality Honda motorcycles Can't kill the bastards, people buy old ones from wreckers and fit them to modern bikes. Also have a spare Big Fuck Off cap -- Surplustronics on Queen St is heaven -- want it as well?

Check that you don't have a threephase generator, the rec is considerably different, and wont help a single phase.

xerxes, a coil might be a good investment. Caps and AC can get "resonant frequencies" that generate fucking MASSIVE voltage spikes (15 thousand volts plus), but if its running all good i don't think you should worry much. Just a thing to keep in mind if it starts doing random things.

Wired1, if a 250rs runs a single phase generator,i would take xerxes up on this offer.

[xwhatsit]

Check that you don't have a threephase generator, the rec is considerably different, and wont help a single phase.

xerxes, a coil might be a good investment. Caps and AC can get "resonant frequencies" that generate fucking MASSIVE voltage spikes (15 thousand volts plus), but if its running all good i don't think you should worry much. Just a thing to keep in mind if it starts doing random things.

Wired1, if a 250rs runs a single phase generator,i would take xerxes up on this offer.

Showing my ignorance here, I seem to recall it is a three-phase. Should know better than to get into these threads

On the subject of voltage spikes, isn't the rectifier turning it into DC before it gets to the battery/cap?

Mike from Cycletreads (Drury Tyres now) has been running his multiple 250RSs with no battery or cap whatsoever, claims no problems, but that worries me slightly (don't understand the technical reasons why/if that's a problem, but it just seems bad ). 5-wire rec/reg, three yellow wires coming from the generator.

When I blew all my bulbs after my headlight went, Ix suggested I get a beefy truck 24V bulb and wire it inline with the generator output, so it's always on. Enough of a voltage drop to keep everything else happy.

[Wired1]

Thanks guys, all good stuff. I have already bought a couple more of the regulators and I'm going to weld a backing plate to the frame where the regulator can get some air so I'm thinking this will all help. I had the regulator loose and tucked in behind the side cover so no cooling help there.
I'm a bit limited in space for a battery - I don't know where they put them normally - but I can probably squeeze a gel cell under the seat as long as it doen't mind which way up it goes!

[xwhatsit]

Looks shit hot!

Can you get the regufier at the top of the downtube?

[Wired1]

Looks shit hot!

Can you get the regufier at the top of the downtube?

It's a long way from the wiring, but I'll have a look. That's where the one on my sportster was and I guess that explains why it was there. My SR has it at the front of the air box behind the engine... I've also got a lot of empty space under the side cover.

[Wired1]

Right. I welded a plate just behind the driver's leg to keep the wiring nice and short, and to act as a heat-sink for the regulator. I picked up the smallest battery the battery man could give me and it is 1.2 amp-hour so running the 3.2 amps I measured with both lights on it should last for 20 minutes or so without charging. I made a battery box out of an old battery acid bottle (how ironic) and wired it all together.
I took the bike for a blast up the road and it was all still working when I got back, until I dislodged the battery negative and this blew the fucken regulator again. Bastard.
Fortunately I bought two of them so I banged the second one in, bolted everything down again and this time soldered the connections onto the battery. Tested it running and it's charging at a nice 14 volts.

Anyway it's been a learning exercise but I've gotta sell this bike to fund the restoration of my SR400 so I've listed it on Trademe for $1500 start price and $2000 buy now - lets see what the public think. http://www.trademe.co.nz/Browse/List...927160&ed=true

Thanks for all your help on this guys.