talking of alternatives for Rotax 912, what about starter motors and stators?

[onetrack]

Starter rotation is always determined by looking at the starter from the nose end. Starter rotation is governed by the starter mounting, which means the starter nose is either pointing towards the rear of the engine, or pointing towards the front of the engine.

[Red]

4 hours ago, onetrack said:

Starter rotation is always determined by looking at the starter from the nose end. Starter rotation is governed by the starter mounting, which means the starter nose is either pointing towards the rear of the engine, or pointing towards the front of the engine.

Thanks, So all my comments regarding rotation in this thread are complete bollox.,  I'll try go back and make notes when I'm at my PC

[Red]

On 10/04/2023 at 1:13 AM, danny_galaga said:

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?

 

 

This is long winded..caution Its entirely possible I've made a mistake

 

 

 

1: The rotax 912 starter:

looking from rear  of engine and rear of starter....the crank rotates CCW...there is one idler gear between the starter and the ring gear on crank

Therefore the starter motor rotates the same direction as the crank when both are  viewed from rear...therefore Rotax starter motor turns CCW when viewed from its rear so CW when viewed from its front/nose

 

2: The BMW F650 Starter:

Looking from the  right hand side of the engine the crank turns CW...there are 2 idler/reduction gears between the starter and the crank so starter turns CCW when viewed from this side...BUT the starter when viewed from this side has its front/nose pointing towards you.

 

So in conclusion if you look at both starters from the nose then the Rotax starter is CW and the BMW Starter is CCW and therefore not interchangeable

 

 

If someone has time to double check all this I would greatly appreciate it

[onetrack]

The BMW F650 starter is most certainly CCW rotation.

 

https://www.ebay.com/itm/305041039675

 

[Red]

Danny

 

Check out this one.. Denso 228000-7460 (as used in Aprilia Tuano 1000 and others)

I think this is the one, cw rotation all the dimensions match, .9KW

Only question is does it have an internal oil seal on the output shaft and it will of course need longer fixings but I dont see that being much of a problem to source.

Edited October 7 by Red

[danny_galaga]

3 hours ago, Red said:

Danny

 

Check out this one.. Denso 228000-7460 (as used in Aprilia Tuano 1000 and others)

I think this is the one, cw rotation all the dimensions match, .9KW

Only question is does it have an internal oil seal on the output shaft and it will of course need longer fixings but I dont see that being much of a problem to source.

I'm still convinced my BMW starter is the one so I'm staying out of this discussion 😄

 

Other than to say all of these motorcycle starters should have an oil seal because they all have the shaft going into the gearbox 

[Red]

Quote

I'm still convinced my BMW starter is the one so I'm staying out of this discussion 😄

 

 

Fairey nuff, But what evidence did you look at to determine rotation of starter?

 

If you take a look at drawings of a Rotax Starter arrangement and videos showing work on the starter gear train and sprag they clearly show the direction of rotation as does the same information for the BMW F650.

 

 

 

 

[facthunter]

It has to exactly right OR it's not worth mucking around and risking it IF something fails it's in amongst the cogs.. One of those drive ends has a pin in a hole in the end for extra strength. The teeth have to have the right dia an tooth pressure angle also.    Nev

[danny_galaga]

Also, I've lost interest in the whole thing. I doubt I'll own my plane long enough for there to be any problems 

[Red]

18 minutes ago, facthunter said:

It has to exactly right OR it's not worth mucking around and risking it IF something fails it's in amongst the cogs.. One of those drive ends has a pin in a hole in the end for extra strength. The teeth have to have the right dia an tooth pressure angle also.    Nev

You are over thinking it, the makers don't vary tooth profiles  between similar starters for obvious reasons, there is even one very reputable Rotax engineer supplying an alternatively sourced part that may well be the one I've found.

You've mentioned this pin before, can you point me to a photo showing this?

 

To give one example of why this type of substitution isnt always the No No you imply, Rotax used to sell a Rotax Branded oil filter that was actually an easily available Mahle type but with Rotax written on it..this I would suggest is a far more flight critical part and substitution was in fact substitution of the same part.

 

I suspect the same in the case of the starter, that it is a Denso unit already in production for other vehicles and is simply re-badged.

This is the whole point of doing the research.

 

Edited October 8 by Red

[danny_galaga]

It's definitely Denso, and pretty much down to one or two models. Just the question of rotation. Surely someone must have a loose Rotax starter they can chuck some jumper leads on?

[BrendAn]

How often do you need a new starter. I would rather pay the extra and get the real thing. Swapping consumables for the same quality but cheaper makes sense. 

[facthunter]

I've made my point and the image was amongst those posted here.. I wouldn't even "up" the starter torque. The mechanism isn't without it's problems, already.. You'd have to be voiding the engines certification. Nev 

[danny_galaga]

21 hours ago, facthunter said:

I've made my point and the image was amongst those posted here.. I wouldn't even "up" the starter torque. The mechanism isn't without it's problems, already.. You'd have to be voiding the engines certification. Nev 

Dunno if anyone is talking about that. Rotax themselves upped it to 0.9kw I think. That later starter is all you need.

[facthunter]

You need to know if the LATER one goes straight on. IF everything's correct no problem. Get it working and FLY. You don't live forever.   Nev

[danny_galaga]

5 hours ago, facthunter said:

You need to know if the LATER one goes straight on. IF everything's correct no problem. Get it working and FLY. You don't live forever.   Nev

This is a different matter, I think we covered it before. The later starter is an upgrade, it replaces all 912 starters. 

[Red]

On 09/10/2024 at 3:37 AM, facthunter said:

I've made my point and the image was amongst those posted here.. 

 it isn't.

no starter discussed or pictured in this thread has a pin in the hole in the end of the pinion

 

I've located  and ordered a used Denso 228000-7460 starter as the appropriate model is no longer available new even from the motorcycle dealers who once used it, they all now supply Chinese copies.

I'll report back to this thread when I find out if it is the direct replacement I believe it to be

 

 

Edited October 10 by Red

[facthunter]

I don't LIE and there is no other place I referenced. it showed the case  that it was attached to with a corresponding place for the pin to run. Nev

[facthunter]

 Cantilevered small dia drive shafts are not  a good design.   Nev

[danny_galaga]

2 hours ago, facthunter said:

 Cantilevered small dia drive shafts are not  a good design.   Nev

But good enough..you see them on Lucas and Delco car starters

[Red]

3 hours ago, facthunter said:

I don't LIE and there is no other place I referenced. it showed the case  that it was attached to with a corresponding place for the pin to run. Nev

No it doesnt

I think you  probably mean the exploded diagram showing installation of the upgraded starter and are confusing the the bolt that both holds the starter together and affixes it to the starter case with a pin protruding from the starter pinion, probably because the drawing is from an angle where it appears to do be in that position...

 

 

.......its not a pin in the pinion hole.

[Red]

3 hours ago, facthunter said:

 Cantilevered small dia drive shafts are not  a good design.   Nev

It doesnt solely rely on the two m5 through bolts it also has a strap holding it to a shaped support, it's clearly shown in the Drawing that you seem to be having problems interpreting

 

 

[facthunter]

jesus mate I've done descriptive geometry and workshop drawing at University and taught it at high school as well.. plus a lifetime of modifying and repairing stuff like this..  Nev

[Red]

Maybe someone else can step in and actually locate this pin that Facthunter insists exists in a picture in this thread?

 

[onetrack]

I can't, despite going through the whole thread and all the links carefully. I've never seen a starter shaft with a pin in the end - a circlip groove and circlip, yes - but never a pin. However, I'm always open to being proved wrong, and just as you think you've seen it all, some engineer decides it has to be done differently.