AF1 50cc

[deacs]

As i understand it the early 90's RS50 predecessor, the AF1 50cc was fitted with a Minarelli AM3 engine, the 3 meaning it had 3 gears, if this was so does this mean that each gear is just geared longer than the AM6 in order to achieve a similar top speed?

[RS_Patrick]

What model and year of AF1?
Only the AF1 Futura 1992 had a AM model Engine
All the others have the RV model engine like my 1986 AF1-50 and my 1989 AF1 Sintesi 50cc, and both got 4 speed gearboxes. (RV-4)

The one i know that had a AM-3 engine is the ETX / Tuareg 50, and the Aprilia Classic had a AM-4 engine.

[williamr]

Just to add to Patricks comments, where there are less gears, top gear is the same, bottom gear is about the same, and the gaps between the gears are wider, so you can't use a very narrow power band without losing a lot of acceleration.

Rob

[RS_Patrick]

Just to add to Patricks comments, where there are less gears, top gear is the same, bottom gear is about the same, and the gaps between the gears are wider, so you can't use a very narrow power band without losing a lot of acceleration.

Rob

Nope there not Rob, there difrent. Top gear is defenatly a lot shorter on a 4 speed, on a 5 and 6 speed the top gears are overdrives.
on a 5 and a 6 speed the first gear is a lot shorter also than on a 4 speed.
Those gearboxes are difrent from 1st to last gear completly.
But with a gearbox with less gears you always need a wider powerband than on one that has more gears.

[williamr]

Internally you're right about higher gears being overdrives on multi speed boxes, but that's compensated by different sprocket sizes so that the overall ratio comes out about the same.

I should have been clearer.

Rob

[deacs]

What model and year of AF1?
Only the AF1 Futura 1992 had a AM model Engine
All the others have the RV model engine like my 1986 AF1-50 and my 1989 AF1 Sintesi 50cc, and both got 4 speed gearboxes. (RV-4)

The one i know that had a AM-3 engine is the ETX / Tuareg 50, and the Aprilia Classic had a AM-4 engine.

hmm i ask because the aprilia owners manual for the 1992 AF1 50cc Futura lists it as having a AM3 engine. check it out at....

http://www.serviceaprilia.com/public/lum/index.asp?l=AF%201

[RS_Patrick]

I know but i never seen an Futura with the AM-3 engine, only seen them with RV-4 And RV-5 engines and AM-5 engines, I know it depents on what country your in wich engine you got.

Also the bike on the picture for the link is not even a Futura but a AF1 Replica (125cc), a 1988 bike. It was folowed in 1989 by the Sintesi wich had bigger brakedisks and some other minor difrences to the bodywork, in 1991 that was folowed up by the Futura wich in turn was replaced by the RS in 1993.

[deacs]

agreed that the photo is wrong but if you open teh actual PDF document the picture on teh actual handbook is correct, its an official Aprilia owners handbook so i presume they know what they are on about. does this RV engine look radically different to the AM series engines?

[RS_Patrick]

Yes, it does, it has the intake manifold on the cilinder it self instead of on the crankcase like the AM has.
Like i said, the manual is probably corect for some countries but the engine difered per country.
Some, if not most did have the AM-5 engine in 1992

[soundisgood]

deacs... Do you have an 1992 AF1? Are you in the US? How much would you sell it for?

[deacs]

nope im in the uk and i have a 1998 RS50 but sadly i have accidently bought a AM3 engine for it instead of the correct AM6!!!

[soundisgood]

I think it will still fit the bike. My understanding is that all the AM's are the same other than the gearbox. I just don't see it going as fast.

[RS_Patrick]

Are you sure you got a 1998 Model RS50? Single rear suspension arm model? Not a 1999 Model like most of us got?
Check here if your not sure: http://www.apriliaforum.com/forums/showthread.php?t=83796

If you told me from the start you bought a AM-3 Engine and wanted to fit it on a RS50 i would have told you that it will NOT fit on a 1999 to 2005 Model. As i said earlyer in this thread, AM-3, AM-4 and AM-5 are basicly the same and the Factory lists most parts for those engines as AM-3/4/5.
The AM-3/4/5 engine is difrent on a lot of points like the axel for the front sprocket, It only fits a 3/16 Sprocket, The AM-6 you can get a 3/16 Frontr Sprocket for and a 1/4

They only made the 1998 model with 3/16 sprockets and a 6 speed, before that it was all 5 speed.
From 1999 to 2005 it was 1/4 Sprockets only so if you got that model i would not fit anything other than a AM-6 engine on it

[deacs]

mine is a late 97 single sided swing arm model. the original engine in it (that ive now removed) was a AM6 (seen on the casting). the engine which i have bought in error is a AM3............... although its yet to arrive from the dubious ebay seller i bought it off! so i may well now have to fork out for yet another engine which will deffo be a AM6 this time!!

[soundisgood]

Thats good to know about the different models... I had thought any AM motor could fit any RS50.

[RS_Patrick]

It will fit but not corectly + the chain and sprockets will wear out with in a few 100km because the sprockets are difrent and not lined up straight.

[deacs]

i dont think it matters anyways, i seem to be the victim of a ebay scammer so i dont think the AM3 engine will ever arrive. looks like im going to have to wait till next month now to get some more cash together to buy a AM6. my own fault for buying off ebay i guess