Has anyone used:
http://cgi.ebay.co.uk/Suzuki-SP370-12v- ... 7C294%3A50
Does it work well?
Any problems fitting?
How easy was the re-wiring that is required to run the lights off the battery?
Thanks.

Hello Mike, sorry, I don't have an answer to your question, but rather I have a question for you. I saw this ad on ebay and was considering the same thing myself. Did you take the plunge? Was it simple to do? I'm not liking having a candle for a headlight and would dearly love 12v lightning, esp with the dark nights now upon us. Cheers, Pete.

Pete, no, not yet. I have a 40 year old BSA with excellent 12V lighting and, having obtained a genuine Suzuki s/h wiring loom to replace the non-standard rats nest on the SP370, I am reluctant to cut or modify it. I planned to phone the ebay dealer at some point but as your need is now greater than mine, perhaps you would like to phone. For an objective opinion on quality/ease of re-wiring it would be worth searching other forums e.g. Yamaha, Honda as the dealer mentions 6V trail bikes from these manuafacturers as well. Mike

Righto Mike,

I'll give them a ring and let you know what they say. I wouldn't be doing the wiring into the loom myself though; I've got a mate who's an electrical engineer and who's built his own trike and he says he'll do it. Again, I'll keep you posted.

Pete

Pete, I e-mailed the dealer and the reply was "Connect the AC lighting input straight to the battery". Perhaps your electrical engineer friend could look at the wiring diagram in the manual and tell us:
1. Does this mean just 1 wire to alter? Which one? (please be specific on the colour and the correct connection).
2. Is it possible for the magneto to supply 6V to the ignition coil but 12V to the lighting circuit? (thinking about cost, I had asked the dealer whether it would be necessary to buy a 12V ignition coil. The answer was "no".) As there are 2 coils on the magneto stator, perhaps only 1 is re-wound to produce 12V for the lighting circuit. Could your EE comment? Thanks. Mike

I have no idea about this Mike, but as you suggest, I expect Billy - the EE - will. Probably showing my profound ignorance here, but would a 12 coil produce a potentially stronger spark, thus aiding atarting? Or does the condenser govern this up to a predetermined limit? Anyway, I'll get on it this weekend.
I'd like top get it done sooner rather than later as I live out in the styx and want the bike as potential 'snow transport'. Did the company say roughly how long it takes to do the stator and return it?
Pete.

Pete, its all electrickery to me! Sorry, i don't know turnaround time.
Looking at the wiring diagram in the Suzuki manual it seems to me that its tailor-made to blow bulbs and overcharge the battery. When the lights are on, the current bypasses the magneto resistor so, presumably, as revs rise, the only thing that may prevent excessive charging is the consumption of the headlight bulb itself! On my bike, it doesn't work out and bulbs blow at higher revs. When the lights are off, excess current is (in theory at least) controlled by the magneto resistor. I assume that excess current is converted to heat and the mag resistor acts as a heat sink. We may never know because the headlight bulb will never blow whilst the light switch is "off"! Mike.

I read and want to add ,why is a dead battery ,or an open , as if no battery present ,responsible for over charging lighting system. on the sp 500 I check headlight voltage with engine running and with ac volt meter. Thanks Larry

On the SP400 I simply ripped up the lighting/charging cicuits and used this back in the day bodge. Disconnect the headlamp wire and the battery wire just after they exit the engine cases. Check the output of each wire in turn. Select the wire that has the most output and tape up the remaining wire. Then run the lights straight from that wire. When one wire is disconnected the output of the other goes up to about 13 volts and perhaps 70 watts. On the road I used to run a 60 watt 12 volt Halogen bulb. For a trail bike this doesn't work as one is chuffing about at lower revs so I use 35 watt 12 volt bulbs which stay bright pretty much straight off tickover. I use a Husky Zenor diode to bleed off the excess voltage.
This runs on AC so you can't use a battery or winkers and you have to use an AC moped horn.
These days you could do the same but use a rectifier from www.electrexworld.co.uk to convert to DC. Then you can use the battery , winkers and horn etc, and a 60 watt Halogen
I talked to electrex last year at the Classic Dirtbike show and apparently you can't do much to uncrease the output since it's controlled by the power of the rotor magnets. I'm an utter muppet with electrics but this bodge has done about 100,000 miles! [Judging by the number of used pistons I seem to have]

I read and want to add ,why is a dead battery ,or an open , as if no battery present ,responsible for over charging lighting system. on the sp 500 I check headlight voltage with engine running and with ac volt meter. Thanks Larry

the two circuits (ac/dc lights/chargeing) ballance each other out. when the lights are off, the regulator resister in the dc charging circuit is in line with the rectifier and battery, and subsequently to earth. the resistor pulling the voltage down to just over 6v in the charge circuit, and also in the ac light circuit, although ther is no load on this as the lights are off.
when you switch the lights on, the resister comes out of line with the charging circuit, so you have just got the rectifier, battery and then to earth. in order to keep the system ballanced, eg both ac and dc to just over 6v, the lights take the place of the resister and pull the volts down.

when you have blown bulbs and your light switch is on, you have no resistence to pull the voltage down as the regulator resister in the charge circuit is out of line in the light switch on possition, thus you cook the battery with 12v as it is out of ballance.
similarly, if your battery is knackered or missing, there is nothing to complete circuit in the charging section sending the system out of ballance again and putting 12v on your lighting circuit, thus blowing bulbs when you turn then on.

cloggy & frogeye1000 I think you guys just helped all of us understand these lighting systems a bit better .Thanks Larry

+1

Thanks frogeye1000.
If a)the battery is new b)all bulbs are OK and correct spec, any idea why after starting the engine, switching on the lights and revving up ....the headlight bulb then blows? Is there another factor at work here?

Which model do you have? Are your electrical components and wiring entirely standard? Is your bike free of charging & lighting problems?

Thanks. Mike

On the SP400 [and probably on the SP370] the headlamp is powered direct from the engine on a different circuit from the battery
If you reread Frogeye, who is far the most knowledgable here, then it makes sense

What voltage are you getting at the bulb. Could be Rectifier/regulater.