I was having trouble with my DT3, it was misfiring, it kicked back on the kickstarter, I was worried that I would break my ankle with it.
I located a company in Germany who made a system for the DT3. They had sold out to another company called Vape.
It's now on my bike, it starts easily, doesn't kick back, I think it's an improvement. 
It isn't standard, but it makes the bike more usable as I enjoy riding it.
The only problem was that I had to take the battery box out to fit a 12 volt battery. 
It also gives you a brighter headlamp too.

I'm considering doing this to my DT2 I'm building up. I noticed when you order the kit from Vape, it has a battery eliminator option. Was wondering why you would even need a battery if the lighting coil would power 12v lighting?

"Battery eliminator option"?  Do you have a link?
Or are you talking about the AC kit versus the DC kit?
 

Hi Steam Biker,
i did the same, Vape/Powerdynamo 12v conversation on my ´75 DT and had the same experience. The Kick-back went from terrible to zero. I think due to more precise and more intense spark.. It really was worth the 300€ and the 180Watt charge power is great. I removed the oil tank/ battery case and welded it to extended by 5mm, so could fit a 2.3AH Battery.
@MarkT, you can chose using with or without Battery. Here a Link

You can eliminate the battery, but if you have indicators fitted, they don't work properly. 
That's why I use a battery. The small square battery from some Honda CG125 bikes fits, but I had to remove the battery box. 
The only downside to the conversion is that I have to charge the battery sometimes. 

I recently installed the VAPE 12 volt kit on my 76 DT400 and am glad I did! It was a pain in the butt to find a battery to fit and ended up getting this tinny little battery that probably wont last more than a year but it only cost $12 on amazon so no big deal. I would highly recommend converting to the 12 volt if anyone is thinking of doing it...

Yes, I know you can run without a battery.  It doesn't work well with signals as already mentioned.,,  and it's technically not legal for street use in the USA without a battery.

I was confused by the wording of "when you order the kit from Vape, it has a battery eliminator option."   I'm still not sure what Bartman512 meant by that comment as Vape also offers an AC kit. 
 

Mark, without me doing the conversion, do you know the approximate cost for a VAPE with shipping to the US?

Sorry, I don't.  The last ones I bought were from Edgar at Powerdynamo before his health failed and he had to sell the company.

I did a comparison a while back and it was a lot cheaper to buy directfrom VAPE than from ebay or a dealer in the US that sells them.

I ordered mine early December, with shipping it cost me $335.49 shipped to Florida.