Advanced Search

I know this is an old thread but it seemed like the best place to post.

I'm doing the electronic ignition / 12v upgrade from Rex's Speed Shop. I have purchased the essential ignition kit and had intended to purchase their 12v additional kit with lights/relays/horn/etc but it was out of stock.

The kit includes the ignition/charging stator, ignition coil, ignition module, voltage R/R

So, what I'm searching for is hopefully a compiled list of the following;

1. The various suitable 12v bulbs (LED might be nice but I can work from the incandescent numbers), including the headlight. I'm assuming a basic 5 3/4" sealed beam, hopefully for motorcycle use. I have an H4 headlight but not positive it will fit. There's a pretty good chance I will replace the stock turn signals with smaller units and store the ones I have, so that might solve itself.

2. Turn signal relay (3 pin or 4 pin?)

3. A suitable gel/solid state/maybe LiFe battery. I'd prefer not to go Lead Acid / AGM if possible. I really like LiFe but not sure the charging voltage will be up to the task.

4. For the horn I think I have a couple laying around.


I've searched a fair bit for a list and maybe it's buried in an build thread or ??? but I haven't found one yet.

Thanks

I bought a  1975 DT250 B in boxes last month and have now assembled it and it runs fine although i am waiting on a few electrical bits as it came with new a rexs speed shop 12 volt conversion and electronic ignition kit which i need to finish the electrics.  The bike also came with a new Circle F exhaust system which i have never heard off, a bigger carburettor and a set of  boyson reeds. 

i have built the bike bog standard apart from the ignition kit as easy to set up but has anyone ever fitted one of these exhausts to their bike and what would the carb starting point be. The pipe basically looks like an expansion chamber for a race bike with a dinky wee silencer so looks like it may be a tad antisocial can anyone advise what improvements is this likely to make to performance, if any, on a standard motor. Regards Larry 

 

My first port of call would be to ask the seller of the 12v conversion. In this regard, how does this one from Rex's (in the UK) look? Might be available in the US.

Sealed 12 Volt Battery fits 6N4 Holders - Rex's Speed Shop (rexs-speedshop.com)

After taking the flywheel off my previousley running DT400 to clean out all the corrosion, it very quickly ceased to run, so rather than mess around trying to breathe life back into corroded components, even though cleaned up, I decided to fit a Rex's Speedshop ignition and 12v conversion.

It all arrived very quickly, instructions were easy to follow, and fitting easy.

The only "problems" I had was that one of the wires from the stator in the conversion was in the "wrong" place, so simply a case of changing it over (according to Rex's there are so many variants of wiring looms they dont always get it right), and the battery was being charged at 20 to 25 volts, easily fixed by adding an earth wire to the engine and then taking it to a common earth point - as recommended by Rex's.

After fitting the conversion it started 2nd kick, and first kick when hot, it idles perfectly, lights etc also work perfectly.

No sign of any kickbacks or difficult starting.

I have no relationship to Rex's speed shop, all I am saying is that from my experience if you are thinking of fitting one their kits, dont hesitate.

I'll probably put the old CDI on E-Bay as no point in hanging onto it.
 

I now have the flywheel off - no dramas.

Behind it was a lot more of the powdery corrosion which I carefully blew out with an air line.

The coils look OK but most of the screws have rust on them - I have managed to clear out the heads to be able to get a screwdriver to engage.

Despite the corrosion everything worked OK, so do I (bearing in mind I am in no hurry) try and dismantle everything so that I can clean everything up and risk shearing the screws off, or do I leave as is and wait until someting fails?

I am tempted to fit one of the Rex's speed shop conversions with ignition and 12v conversion and bin the old corroded items: www.rexs-speedshop.com/product/dt360-dt4...th-12-volt-lighting/
 

where do you install the regulator on the bike? i installed one splicing it the yellow wire after the mag. It didnt work. Do you have any ideas?

I  used the Rex's Speed shop version.
www.rexs-speedshop.com/product/yamaha-dt175-12-volt-conversion/

very easy to install and no mods to the stator needed.

the unit is a 12 volt voltage regulator that replaces the stock one and it runs a 35 watt or up to a 45  watt headlight very well.

Hi Jammyyammy, I bought the 12v lighting/charging coil conversion from Rex's for my bike, although mines a 75 DT 250B.  You only need the ONE 12 voltage regulator/rectifier supplied by them.  The VR controls the AC lighting circuits you identified in your drawing by simply 'T'eeing into the headlight circuit which is typically a Yellow wire.  The rectifier converts the AC charging supplies (Green/white for daytime running - key position 1 or Green/Red for nightime running - key position 2) to DC at approx 14.2Volts which then charges the battery.  The standard DC system on your bike is not hugely load sensitive and a good battery can easily accomodate the small load changes involved and hence does not require regulating.

Hope this helps. Andy. 

It does not say anywhere but I am sure they send instructions like they did for my 1978 DT175 12 volt conversion. there is this in the listing.
Important: he F3T351 flywheel is a reduced depth item – the person fitting the kit MUST ensure there is clearance between the flywheel and any lighting coil fitted BEFORE starting the engine.

• Highest output self generating ignition available – no other system comes close to the spark power.

• Adjustable stator AND model specific ignition timing curve gives an unbeatable combination.

• The billet stator accepts a single stock 6 volt lighting coil*.

• Uses the standard flywheel for low vibration & tractability.

• Best for starting hot or cold, sparks from 150 RPM.

• New high power HT coil included

Capable of powering twin spark plug heads at full power, unlike other systems that lack sufficient power to do this.

*Only works where one single lighting coil is used – remove your flywheel and check first. Yamaha modified generators under service bulletins so you must see what system is on your machine, we cannot look for you.

Thanks Mark, Rex's is a bit arrogant aren't they? I like their 12 volt conversions as I have one on my DT175, it was easy to install and it works great.

The scary part was both old source coils showed resistance in spec, I determined it was the only thing holding things back by turning the magneto at a faster speed and watch the spark break up.