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DT400C 12 volt conversion

  • Rexs Speedshop
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Replied by Rexs Speedshop on topic DT400C 12 volt conversion


Yes, there are 5 options on the single source coil kits. An 'A' winding is for more high speed work and E is for Trials where great starting, idling and low end power is important. The CDi and the winding work together to give the timing curve, we can change the CDi to shape the curve BUT you have to know what you want - we're electronic engineers not engine tuners! These are great kits but they do run out of puff at very high RPMs. The 'A's are wound to give much better top end performance - the RMK-3 comes with a 'B' winding. The trials versions that will be out there soon run 'E's. This still runs at high RPM but its very out of breath once you go above 3/4 of the RPM range - its extremely rare to use this range on a Trials machine so they prefer to have all their power low down.

And just when you get your head round that we're nearly there on a "dual power" system which has a double source coil, one which is optimised for low speed and one for high. This one the CDi unit entirely controls the timing curve and it does not run out of puff at very high RPMs, if anything the output becomes higher the faster you spin it and it will allow RPMs over the standard red line. There will be single timing curve boxes and variable. The Variable one lets you TRIM the static timing point at the box, no messing about moving the back plate and it'll shape the curve.
Electronic Ignition Design & Manufacture*12 Volt Conversions*Electrical Parts*Generator Rewinds & Overhaul
09 May 2015 04:24 #21

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Replied by Makotosun on topic DT400C 12 volt conversion

Very cool!
IF it isn't one thing, it's another.
09 May 2015 10:56 #22

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Replied by relic on topic DT400C 12 volt conversion


Firstly, thanks for sharing your knowledge with us.
You've read about how I rewound my 400 lighting coil?---I hope your shop has an appropriate meat grinder? :haha I think I'll pull the stator cover off and have a look for signs of overheating based on what you are saying. Just to be safe.
I am running a large capacity regulator, from a Suzuki Burgman scooter, (they have a huge electrical load---grip warmers, power points, power mirrors and windshield etc) and my initial thought was that it would be more than enough to handle whatever my rewound coil could produce. Any thoughts on this?

Relic
I wonder where this goes...?
Daily riders-1976 DT400C, 1972 Suzuki T250 Hustler, 1971 Hodaka Ace 100B+, 1974 Moto Guzzi Eldorado.
Last edit: 09 May 2015 11:24 by relic.
09 May 2015 11:19 #23

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Replied by Rexs Speedshop on topic DT400C 12 volt conversion

We have a couple of CNC winding machines so no meat grinder needed! :lol:

Well its been working fine so must all be OK! Really though you don't need a big regulator unit - a coil like this is never going to make much more than 120 watts due to the volume of iron around which the copper is wrapped. This is why we stick with supplying the lights with AC as to rectify power there are losses in the regulator/rectifier. If you use AC there are no losses so more power available for the main headlamp.

It does make the winding more complicated to make as you have to stop mid wind and create a tail for the lights to be fed from but it does leave more power for the head light and it means there virtually no changes to the bike's wiring loom or switch gear. The only change is a new combined 12 volt regulator/rectifier and the wire that went to the old separate single phase rectifier is left disconnected.

We've ironed out all the bugs with the XT250/500 kits now we will be rolling out these kits for more bikes. The biggest problem now is getting hold of the old APF fitting bulbs in 12 volts!
Electronic Ignition Design & Manufacture*12 Volt Conversions*Electrical Parts*Generator Rewinds & Overhaul
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Last edit: 10 May 2015 01:36 by Rexs Speedshop.
10 May 2015 01:24 #24

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Replied by bluntz465 on topic DT400C 12 volt conversion

Glad to have this confirmed,Also I am modding the stock coil since I am going with LED's so need no more amperage.Thanks for your input!
1957 Cushman Eagle 1969 Honda 90 ATC 1969 Honda CB250
1973 Yamaha AT3 1974 Kawasaki KH440 1974 Honda XR75
1975 Suzuki TS75 1975 Kawasaki GreenStreak 90 1975 Suzuki GT550
1975 Suzuki TS250 1976 Suzuki GT550 1976 Indian Chief
1976 Yamaha YZ80 1978 Yamaha IT175 1980 Suzuki GS550
1982 Yamaha IT465J
Last edit: 10 May 2015 05:52 by bluntz465.
10 May 2015 05:49 #25

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Replied by PMK on topic DT400C 12 volt conversion

Reviving an older topic.

Rewinding the generator coil and reconfiguring the motorcycle for 12 volts appears fairly straightforward based on the excellent info posted by Relic and others.

This was done on a CDI equipped 76 DT400. Has anyone done this on a non electronic ignition RT2 or similar points type ignition?

Would like to build the Rickman Yamaha using a 12 volt system, with DC output allowing me to run LED headlight and taillight / braklight.
22 Oct 2019 03:28 #26

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Replied by Dallasdt on topic DT400C 12 volt conversion

Hi I am performing this right now but what’s not in this write up is at what point do you start the 2nd tee Off. On the original it starts at about the 2nd level of windings and runs about half way across. In the write up it says you can get up too 5 layers so do you still put the teed line on the last wrap or the 2nd ? 
 
22 Jan 2022 18:08 #27

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