aprilia af1 125

[derbi x-treme]

i may be buying one of these soon and have a few questions. well its a 1990 version and looks pretty good to me.

i have only used 50cc twostrokes so am wondering will this bike have a powervalve, if so how do these work and how do you make them give the bike most power, if not will this bike be slower in comparison too ones that do?

also does anyone know anything about these bikes in general performance reliabilty etc?

lastly how well will this 17 year old bike be able to keep up with mdern rs125 and cagivas?

thanks any help would be great

[derbi x-treme]

sorry meant to post this in the workshop section, not sure how to move it, but then again its kinda relevant to new bikers anyway

[Jayd]

The AF1 will be a 2t, and I think it may have a powervalve. Its a very similar bike to the RS, engine included, I think its a Rotax 122 though, instead of a 123 or something like that.

[rocket_richie]

my mate had 1 back wen i was riding my rs125 it was just as quick. make shur it has a looong sevice history and is low milage. it did have a powervalve same as the rs
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rs50 x2 rs125 zx6r f3 gs500e gsxr 400 zx6r f3

[Kickstart]

Hi

Depends exactly what model of AF1 it is. The registration year on the UK docs is quite often in fantasy land.

1987 model AF1 had 16" 3 spoke wheels and the Rotax 127 engine. 28mm carb. Steel frame. Single sided swinging arm. Normal forks. Top speed of about 94mph. Used a power valve, which was gas operated (opened by exhaust gas pressure at the required revs, adjustable). Most were sold in 1988.

1988 model AF1 Sintesi had 17" wheels, 7 spoke front, 9 spoke rear and the Rotax 123 engine (as used by the RS125 for quite a few years). 28mm carb. Alloy frame. Single sided swinging arm. 38mm USD forks. Top speed about 98mph. Same power valve setup as the 1987 model. Sold in late 1988 and 1989.

1989 model AF1 Sintesi was very similar to the 1988 model. But had a slightly pointier fairing, no fuel gauge and an electronically controlled powervalve. Very late versions had the 34mm carb (but not officially imported like that).

1990 in Italy the AF1 Futura came out (but not in the UK until 1991). Alloy frame. 34mm carb. 5 spoke wheels. Early ones had the 38mm USD forks, later ones (and all UK ones) had the 40mm USD forks. UK ones had twin round headlights with a tacky rubber surround, other markets got them with a single letterbox shape headlight. Top speed about the same as a Sintesi, but a fair bit more power.

Power valve used on the Rotax engines effectively raises the top of the exhaust port, which increases exhaust port duration and means it opens sooner. This gives more power at high revs at the expense of loads less power at lower revs (hence the power valve lowers the exhaust port at low revs to get some power back). A power valve does not give an engine more power, if merely means that they could tune the engine to produce more top end power without it being unrideable at low revs.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[derbi x-treme]

thanks alot for the help guys especially kickstart it was really useful well heres a picture of it so hopefully someone knows which model this is.

also does anyone know any shops where i can get performance parts for this bike

https://img292.imageshack.us/img292/1041/1d31ie9.jpg

thanks

[Kickstart]

Hi

That is a 1989 shape model (so 1990 on the registration book is probably right), repainted with non standard front indicators and mirrors.

To be honest I would check how it goes first (and make sure the power valve is not in upside down.....). Think they respond well to a 34mm carb, but beyond that you are likely to just be loosing reliability quicker than you are gaining power.

Also they were originally set up to use 98 RON fuel.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lubbe93]

Just rebuilt the engine runs a beaut. Just about to start the body work over the winter just thought id upload a picture to show people my bike as they are getting very rare now! absolutely LOVE this bike!
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dlubbe

[kerr]

Iv got one too (not that rare ) how is the electrics on yours, mines are a bag of old shite, have had to replace quite a lot, mainly because of previous owners bodges.
picture whorage

https://i266.photobucket.com/albums/ii265/BIGKERR/20130806_125501.jpg
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aprilia 125 Af1 Futura >> Suzuki gsxr 600 srad >> J1 zx6r >> cbr 600rr >> Speed Triple

[Lubbe93]

Funnily enough thats one of the things ive been doing today just tiddied all the engine bay up all new connectors on and sorted out where it was all running. But nah the electrics have been sweet on mine mate, i really like yours tho. Since that pic ive uploaded, ive done the wheels and tiddied a few other little things but the picture is too big to upload. But the cowboy i brought this off said it only needed a top end rebuild well put it this way i rebuilt the whole engine only
Thing that looked unused was the gearbox! But was all worth it to now have 38bhp out of a 125 running sweet and reliable...
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dlubbe

[Kickstart]

Hi

UK spec one, so actually a bit rare.

Where did you get the idea of 38hp from? Road tests in the UK managed a shade over 28hp.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lubbe93]

Oh i was talking to a specialist, who said standard they're 34hp with the 34mm carb, and with a 28mm carb they're 28hp. Maybe thats wrong? But then the engine is basically forged well forged piston and conrod, big end. Top and raised exhaust port. Apparently brings it up to about 38.... But maybe im wrong
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dlubbe

[Kickstart]

Hi

Claimed with a 34mm carb they were 33hp I think (about when Aprilia gave up with power claims), which landed up at a shade over 28hp at the back wheel.

Getting one of those Rotax engines up to 38hp would require a hell of a lot of work.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lubbe93]

Oh! Maybe its ballsh*t then. But its deffiantly fast enough, i changed the gearing so its now 38 tooth on the back and 15 (i think cant remember lol) but correct me if im wrong but standard they're 37 front 16 back?
By the way, what actually is the difference between the import then? Mine has twin headlights, speedo is in kph too? Weird for uk spec

Many thanks
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dlubbe

[Kickstart]

Hi

Not 100% sure off the top of my head but think the standard gearing is 16:38.

UK ones had the twin small round lights (which are about as effective as 2 glow worms in jam jars). They all had kmh speedos, but normally a sticker overlay when new. Think they were supplied new without the power valve until you could prove you had a full licence (I bought mine pretty much new, and the power valve kit arrived for when it was about run in). Came with the 34mm carb.

Early shape UK ones (like yours) also came with the later forks. An import of that shape would have the older 38mm USD forks and a different front mudguard.

Speedo is in cloud cuckoo land. Had mine round to an indicated 180kmh / 112mph, but reality is the top speed is around 99mph if in good condition.

By the way, some Suzuki GSXR mirrors have the right bolt spacing to go straight onto the AF1.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lubbe93]

Yes headlights are useless! Lol i was going to try and HID them...? Oh yeah mine hasnt got that sticker on the speedo, a friends clocked me on it at 111mph in his type R next to me... With standard gearing. its got the valve and everything. No restrictors. Goes like a rocket really does. Yes the gsxr 1300 mirrors bolt straight on dont they? I do want to get some i think. Know anywhere i can get a screen?

Thanks Dan
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dlubbe

[Kickstart]

Hi

If you find someone making a decent looking screen to fit then let me know! Forgotten which model of GSXR the mirrors come from but a half decent bike dealer can look it up in the HiLevel catalogue (I think) which has the spacings marked in it, and pattern GSXR mirrors are available (I have them on both my Futura and my Sintesi).

On your gearing 111mph would require about 13000rpm, and about 12000rpm on stock gearing, both a long way past peak power and requiring about 20% more power than they have as standard.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[kerr]

I (think) gsxr srad mirrors are a straight fit, sure one of mine's is from an srad.
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aprilia 125 Af1 Futura >> Suzuki gsxr 600 srad >> J1 zx6r >> cbr 600rr >> Speed Triple

[Lubbe93]

Well ive got another guy i spoke to who can get me brad new one for £50? Wasnt sure if that was cheap or not but ive kept him in mind can give you his email...? His names ivan from
Dorset.

That was with the gearing that was on it, perhaps wasnt standard then, will have a look at that.
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dlubbe

[Kickstart]

Hi

If it is a standard screen then yes I would be interested. Mine has a black aftermarket screen on it.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lubbe93]

Ok well shal i message you his email address just say ive heard from a guy on a forum you can find a screen for your bike he gave me your email could you help? Hes a really helpful guy should be ok.

Many thanks
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dlubbe