Harley Davidson EFI Hardware

[glider_fuel]

I am also waiting for Microsquirt. Planning to convert existing Marelli EFI to uS then do fairly major engine build on a dresser.

Still in research mode until I can get a box.

I have the service manual for my bike and theres lots of good anecdotal stuff in there. I would recommend getting as complete a setup as possible from the donor bike. Wiring harness etc. Access to the shop manual for that bike ought to help a lot for pinouts, and sensor parameters. There's a fair amount of stuff on line. If you grab bits related to a 98 road glide I can help you directly with that.

Modern evo EFI HDs are using a 36 -1 toothed wheel setup notched into the crank/flywheel left side. I think the Twin Cams are doing the same but I'm not sure they are using the same tooth count. The sensor pigtail is visible up front where it interferes with the oil filter. Then theres the "cup" on the cam for cylinder reference. Hall Effect Sensor there.
Also remember that the cylinder firing events are unevenly distributed. Taking RPM/Tach indication from this at low speed is a concern I have. It appears that the basis to use these in MSnS is there but it's alpha code. That's the part I think looks fun. (OK i'm sick).

There is an engine oil temp sensor in the rear (?) rocker box that serves as engine temp/warmup indicator. No knock sense on the Marelli. Not sure for VDO or Delphi. However Knock sensors are fairly engine specific. It might serve to avoid one initially and get everything tuned by hand first. I have seen lots of traffic on threads about wierdness inserted by the "wrong" knock sensor messing with timing and early setup.

What sort of Bike/Engine are you building? Sequential or Batch Injection?
The Injection on my bike is sequential (Squirts with the Spark) but it's Alfa-N so no O2 sensor and no MAF. uS has a Hybrid Alfa-n mode that looks promising with "lumpy" intake vacuumn but an added O2.

Not to bash the uS but... simply grafting a complete HD system on and finding proper editing software, may be the most direct route if your engine isn't too "non Standard".

Stock modern gas tanks have the road worthy efi stuff built in at the factory so you done have to mess with it. 2 Bar pressure for marelli, 3 Bar for Delphi. I'm a safety nut and dont like flaming gasoline in my crotch (but then who does?) so if it was me I'd just swap the tank wholesale for one that had the "right" stuff.

Good Luck. I look forward to reading of your success.

[A McNeill]

I can't say that I know 135' is incorrect for certain, but bear with me for a moment. HD engines are a common-pin, 45-degree V-twin. When the front cylinder is at TDC, the rear is (necessarily) 45' ATDC. When the front cylinder in on TDC-compression, the rear cylinder is on it's intake stroke. From there, we can do some simple math to determine piston and valve events (as opposed to spark timing events). If the front cylinder fires at (for arguments sake) TDC (TDC-compression), the engine will rotate 315 crankshaft degrees (360 - 45 degrees) before the rear cylinder is at TDC-compression and ready to fire. It must now rotate 405 degrees (360 + 45 degrees) before the front cylinder is back to TDC-compression. So, piston events are 315 and 405 crankshaft degrees apart requiring 720 degrees of crank rotation (obviously). Short of re-designing the crankshaft and case assembly, this will always be so.

If we assume (and it is an assumption, I don't know for certain) that both cylinders are running the same amount of spark advance at any given moment, then spark timing should follow the 315/405 pattern (assuming static RPM and load). 135' after F TDC-compression, the rear cylinder is still 180 degrees away from firing and it follows that 135' after the rear cylinder fires, we're still 270 degrees from front TDC-compression again.

Just my .02

[Dr.Hess]

I bought a Buell TB, manifold, injectors and fuel pump to do my wife's Sportster. From my net surfing, I think the injectors use Ford connectors. Anyone have any ideas on what the throttle position sensor uses?