Yeah, I think Keihin slowed down manufacturing on certain carbs or something, and which caused the price of these carbs to skyrocket. The pumper carb traditionally was the only way to go if one wanted to increase throttle body size without losing out on engine responsiveness. EFI has the potential to surpass the carb on both.
There have been EFI DRZ conversions before, but they were built around the ecotrons kit:
http://www.ecotrons.com/products/small_ ... ction_kit/
While evidence of such is largely anecdotal, a general consensus was that the kit and the parts within were of questionable quality at best. Additionally, these kits lacked an accurate method of crank position, as it relied on picking up on a 2 tooth pattern on the flywheel. This lack of precision caused the converted bikes to have trouble running a smooth idle and had generally rough running anywhere below 4000rpm. So a few years ago, a thumpertalk user by the name of roleyrev went back to the drawing board and started from scratch with the intent of creating an EFI DRZ that would most closely resemble an OEM EFI DRZ:
https://thumpertalk.com/forums/topic/12 ... ected-drz/
The DRZ400 platform essentially shared the same engine from the LTZ400 quad, which received EFI in 2010. Some parts are interchangeable, specifically the throttlebody (36mm) with its associated injector, MAP sensor, and TPS sensor. It is unconfirmed whether or not the airboots and manifold boots are swappable, but it is possible to use either 3d printed adaptor fittings or DRZ E-model airboots to fit the throttlebody to the bike. Crucially though, the LTZ400 flywheel does not fit in the DRZ bottom end (ltz400 bottom end does not fit in the drz frame either). However it did give an important detail: the crank position pickup was achieved with a 18-1 tooth pattern.
The original method for converting a DRZ flywheel was to machine off the stock two-teeth pattern on the DRZ flywheel, then to mill a custom flywheel trigger ring out of low carbon steel. The ring, milled with a 0.015" interference, was then heated in an oven then slipped over the flywheel. Since this requires about 60-80 hours of machining time, alternative approaches are being looked into. Right now, I am currently negotiating price points for a trigger ring part.
The fuel pump on roleyrev's bike is a 25L/hr unit which offers an integrated pressure regulator, which allows for simpler routing. However, if the calculations are correct, the pump is only good enough for 55hp. So while it would be sufficient for more mild builds (majority of drz builds), an alternative pump would need to be sourced for high power builds.
The stock petcock is a vacuum petcock, and does not have a port for a fuel return line. While the current method is fabrication of a custom petcock (steel plate with two steel tubes welded in), there is a good possibility the stock petcock can be readily modified to take a return fuel line.
The coil pack is replaced with a coil from a Nissan S15 to allow for sparkplug triggering directly from the ECU.
As I've stated before, the ECU is currently a microsquirt ECU. If nanoEFI could be used, I would love to be able to beta test for it, especially since from a development side I would only require an ecu and nothing else.
While I've hit most of the hard points here for the conversion, I'm sure there are some more details I'm forgetting about. Will post more as I remember.
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