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1

General Two Stroke Talk / YZ 250 EFI

« on: July 21, 2013, 11:57:07 PM »

The YZ is using a small jet into the intake stream just behind the throttle body. It's programed to only open after 60% throttle. Works well. Although I'm designing a smaller electric ( UCU ) driven pump, smaller than a match box for accurate oiling, this will be feed straight to the bigend.

Clever, I've been looking at the Aprilia oil pulse pump 8222708 from the '00-'04 SR50 Ditech and '04-'08 SR50 Ditech Factory, pretty much fits your description. $126 new from AF1 Racing. Pulse from ecu based on load and rpm should be perfect.


The flow rate should be enough to supply the 250, it's capable of much more than the 50 requires to allow rapid bleeding of the oil lines. Would have liked to have found this before designing an oil pump, could have done my project on the actual injection system which would have been a lot more rewarding.

So you intend to plumb directly to the big end feed holes in the crankcase and let it disperse into the top end from the crank spinning? I'm imagining some little brass feed tubes from around the reed cage area then into the feed holes, but I'd be concerned about them breaking off with vibration, maybe some silicone hose might be appropriate. How will the pressure pulses in the crankcase affect the pump?

2

General Two Stroke Talk / YZ 250 EFI

« on: July 21, 2013, 02:19:36 AM »

Awesome project Uniflow!
I'm looking at doing a similar thing with my registered 02 YZ250 motard, primary injector in the transfer for idle and light load, secondary in the throttle body to keep the crankcase cool. What oil pump are you using? I've been looking for a small one for a while, I even designed one for a final year engineering project, but wasn't very successful. Oil pump would be awesome on the street, stock tank gives me about 100km range