Does anyone happen to know what other machines the starter and alternator appear on? I forgot to have a close look at the starter while I had the engine out, but I'm pretty confident it's a Denso. That makes sense since they also use a Denso solenoid (it does not necessarily follow, but as a manufacturer, if you've decided a companies starter motor is of high enough quality for you, then their solenoids should be too so why not stick to one supplier). Likewise, there seems to be a good chance the alternator is a Denso too. If not, following my logic, since the reg/rec is Ducati (which is probably Magnetti Marelli) then maybe so too is the alternator. That makes me sad, because if it's Magnetti Marelli, they kinda blow 😄
I have been having a bit of a look around while I compose this, and so far I have found these which are specifically for the 912:
https://ecclestonaviation.co.uk/product/889751-electric-starter-set/?v=79cba1185463 (Rotax OEM 500 squids, plus freight)
https://www.aircraftspruce.com/catalog/eppages/skytecRX12.php (improved aftermarket. 700-900 USD, plus freight. )
So going with my hunch, I started looking at pics of Denso motorcycle starters. Those superfluous lugs are a clue they normally bolt to a crankcase) I hit on the BMW F650 starter. It will need further investigation, my friend has a BMW F650. I can have a squizz, but not sure if I will have enough access. It certainly makes sense, since the F650 is also a Rotax engine. Single cylinder, so it would need ROUGHLY the same amount of force to spin as the 912. As well, someone else here pointed out that the F650 radiator cap is the same. What this is adding up to is that Rotax, naturally enough utilise what they are already getting for other engines they make. Of course the F650 has been around a while, so there may be a few iterations of the engine, which could include the starter. So even if it is the F650, we need to determine what years it used the same starter (if of course it is the same)
The below link is for an AFTERMARKET F650 starter. Before anyone jumps the gun, I'm showing this link because it has quite a few pics from different angles. It is my preference to buy the same genuine part that Rotax buys, but paying the automotive price. I probably wouldn't get a cheap aftermarket starter.
https://www.stein-dinse.biz/product_info.php?language=en&products_id=524427#prettyPhoto
Too see exactly the same starter, it's useful to look for genuine second hand ones on ebay:
https://www.ebay.com.au/sch/i.html?_from=R40&_nkw=bmw+f650+starter&_sacat=0&LH_PrefLoc=2&Brand=BMW&rt=nc&Brand%20Type=Genuine%20OEM&_dcat=177959
Particularly this listing
https://www.ebay.com.au/itm/394431030976?hash=item5bd5ebe6c0:g:jbIAAOSwnQFjzr7C&amdata=enc%3AAQAHAAAA4BBbngib0YSE%2B6CMmjsCmTpUvXc9UZlt%2FfgQCtHur%2FN9tqAkwgwYcHrHWpcLICJlLUbPp3XbvdKtGA8KIW8R6raYzZcfQYI0gQP49M%2BQY7usc%2BqH%2BZgmY0sZwBeQTl%2BNZc0ab28Ev9pQvqeWGiUBDs7neO3lXe04bVr5ghxLIJleIFF8myKupAhmW1pZ09HT0OJTyX8IxFAibhoV%2BbPQavFTrJVmbVjI%2FPEtKbpSloRToz3CqwbwFicn6kkY7jWDj8A7psox9wg3rixECg3cM6Dl8EyZMoU3uWE%2BNtcoEv0E|tkp%3ABk9SR9K2rIXtYQ
Of note, they clearly show the Denso part number ( 428000-5630 . Also 294 359 ) which is useful, should this turn out to be the correct starter. Again, gun jumpers, please I'm not intending to fit a second hand one unless I knew where it had been (only from a known 912 engine, not from a motorbike thats probably been submerged in rivers a number of times in its life 😄 ) If I'm reading the listing correctly, it's for models from 2006-2012. Italian listing, so not sure how well they translated it. They could mean only 2006 and only 2012, but that seems unlikely.
Note that the Aircraft Spruce link also has some handy drawings with dimensions.
Note that I'm attaching the pics from that ebay listing for posterity since ebay listings disappear after a while.
The last pic (the clean, silvery one!) is of the genuine starter, for comparison from Ecclestones site. I am specifically only looking at the late model starter, as I believe the Black starter wasn't as powerful and should be upgraded anyway.
NOTE NOTE NOTE NOTE!!!!
I'm NOT saying this is definitely the same starter, but it's looking plausible. Something as simple as the wrong number of teeth on the armature could blow this out of the water (This starter has 9 teeth).
Does anyone know anything else?