Deep dive, Sintesi 88 - type EH

More than any other generation, the 1988 Sintesi AF1 125 was a huge jump forward and offered the 125cc class features rarely seen on superbikes let alone on learner legal motorcycles. At the time it was compared to the mighty Honda RC30 superbike racer for the road, which is high praise indeed, but again this was a 125cc motorcycle you could ride at 17 (UK) making it even more remarkable.

The updates over the previous Project 108 model were considerable with the new bike featuring all-new bodywork including twin round front headlights, GP inspired radiator openings on the fairing, separate seats for the rider and pillion, with the pillion seat colour coded to give the elusion of a single seat unit. The metal fuel tank hinged upwards to gain access to the spark plug, battery and coolant reservoir. The stock Sintesi gained bold new graphics with a purple colour band which were very much in-tune with the younger generation of the era. For the UK (and export) market we gained the classic Reggiani Replica with striking graphics and the number 6 proudly displayed on the tail piece. This bike featured heavily in the UK media and helped put Aprilia firmly on the map.

Chassis updates include:
All new twin-spar aluminum frame - significantly lighter and stiffer over the steal frame it replaced.
Alloy 'rear set' foot rests for the rider and pillion.
38mm upside-down fork - 4 years ahead of the Japanese
Single-sided swingarm and APS suspension - carry over part from the project 108
New 17" multi spoke wheels - sizes: 100/80-17 front and 130/70-17 rear
New 320mm floating front disc brake with a four-piston calliper

Engine updates include:
The new Rotax 123 replaces its predecessor, the 127, and remains a mainstay of the Aprilia range up until 1994, when it was replaced by the Rotax 122. Here are the most important new features:

New aluminum cylinder with Gilnisil-treated liner
New two-piece cylinder head for improved cooling.
Stroke 54 x 54.5
Compression ratio dropped to 15:1 (15.5:1 on the Replica).
Balancer shaft (not present on the Rotax 127).
Dell’Orto PHBH 28 RD oval-section carburettor.
Rave 2 pneumatic power valve
New airbox with dynamic air intake mounted on the right side of the bike.
Maximum power output of 28.66hp at 10,500 rpm

A, B and C versions
In early production the fuel cap is located on the right hand side of the fuel tank and without the breather hose, with the vent integrated in to the fuel cap. These early models can be identified by the codes "A" and "B" which are visible on a decal on the seat subframe.

All subsequent production bikes have identification code "C," on this version the fuel cap moved to the left side with an additional external vent on the right.

Left side, AB fuel tank, right side C fuel tank

Colours

Black, purple, white and red

Dark blue, aquamarine, white and red

Replica

There is a forth colour that appeared in a bike listings catalogue which I am not 100% clear if this was a pre-production colour that got dropped for another option, a low production colour (I have not seen another one?)or even a colour mishap in the print process!

Black, green, white and red

AF1 125 model variants and how the UK models fit in

Following on from previous posts on the UK specification Futura bikes I have done a little additional research. To date I can confirm the UK 1992 Sport Pro bike is 100% a GE model as I have had this confirmed by a frame number on an owners bike. I am still waiting on conformation of the UK 1991 Futura with the FM style seat unit and colour scheme, however we know that the frame, fork, swingarm, mudguard etc are all GE spec, so for now I am categorising it also as a GE (UK) bike until proven otherwise via a frame number.

Here is a simplified version for all the AF1 models and how the UK bikes fit in to that timeline.

And to separate out the officially imported bikes in to the UK, we had:

My bike - previous engine work

Here is a little more history on my AF1 I found while going back over some old messages from the previous owner.

3rd July 2022:
"When we got it, the bike had been stored for 10-ish years but I cleaned the carb etc and it ran very well. After putting new tyres on etc and a fresh MOT, on its first ride it spat a load of gearbox oil out. After pressurising the crankcase, I thought it was crank seals so changed those and it made no difference, so I ended up splitting the motor down and saw that the gasket between the crankcase and gearbox had gone, so changed that and checked everything else as I went. One of the best Rotax lumps I've ever played with to be honest"

Magazine, International motorcycle catalogue 1988-1989

 The 'International Motorcycle Catalogue' was a model listing directory published annually. I had several from period and I am missing the 1990 one with the Futura generation in, if I find it I'll update. Here are all the listings for the AF1 series.

My Bike at the Classic Motorcycle Mechanics Show, Stafford 11th - 12th October 2025

After finally getting my bike fully assembled and in one piece, it was time to pack up and take it to the 2025 Classic Motorcycle Mechanics Show in Stafford.

I entered the bike as a private entry, and it was allocated a space in the Retro Hall, just off the main exhibition area. Unfortunately, the layout wasn’t clearly marked, so exhibitors were left to choose their own spots. The space I ended up with didn’t really do the bike justice — the lighting was poor, and the location felt a bit tucked away. To make matters worse, there were several empty spaces in the main hall’s private entry section where the bike would have been far better showcased, both in terms of visibility and presentation.

Despite these challenges, the weekend turned out to be a great success. The bike stood out and managed to pick up a ‘Highly Commended’ award, which I was absolutely thrilled about — especially considering it had only been completed a week before the show!

Throughout the weekend, I had the chance to chat with a number of visitors who had owned an AF1 back in the ’80s and ’90s. It was fantastic hearing their stories and memories of this iconic Italian pocket rocket — the nostalgia and enthusiasm they shared really added to the experience.

In addition to my AF1, I also entered my Honda MBX on the Retro Mopeds stand. You can read more about that experience here.

along with my Honda, safely lashed down in the back of a van

My bike, seat covers

 This last weekend I managed to finish up fitting the seat covers. I had ordered these covers from an Italian company called Volcano Industry  based in Sicily (probably named after Mt Etna!) who I originally found on ebay. 

The kit turned up fairly promptly and had a run of elastic sewn on the edge which you can use to staple it to the seat base. The kit is very tailored and fits very snuggly, so a little effort is needed to pull it around and get it in the right place, an extra set of hands would be useful! 

The end result is as good as the original if not better, the cover follows the curve of the foam and looks factory. Volcano also can offer alternative colours for the back pad for Sintesi use.

Bottom line: I am super impressed, Volcano have over delivered in quality, fit and finish and I can't recommend them highly enough. If you are restoring a Sintesi, buy this kit.

Full disclosure: I paid full price for this kit, I just believe in praising and recommending a great product when it warrants it. 

https://www.volcanoindustry.com/shop/seat-cover-aprilia-af-1-sintesi-1989-1992/

my bike, decal kit

My decal kit arrived from Italy today from Decalmoto.com First impressions are that it looks fairly decent for the money, I'll give an update when I start to install it.

Note: The green looks more green in the flesh, maybe my camera/ office/ monitor makes it look more blue than it is? 

Join the new Facebook Aprilia AF1 group here: https://www.facebook.com/groups/apriliaaf1

Pre-production Project 108 AF1 Replica

Here is a great picture from the 1987 Milan motorcycle show showing the Replica version of the AF1 Project 108. As you can see the bike has slightly different colours with red on the tank and more green on the side panel and a green number spot on the tail, but the biggest change is that it also features a single headlight. 

It is common for manufacturers to display non-production ready machines or display machines in differing colours to test the market, or maybe the headlight fairing just wasn't ready in time for the show? I have also heard that twin headlights only became legal in Italy in 88, so maybe aprilia updated the bike to take advantage of this, but that needs fact checking. Either way its another piece of the model time-line.

image 1987 Milan Motorcycle Show

production version of the AF1 Replica

My bike, restoration plan and goal

This last weekend I had displayed my Honda MBX80 at the Classic Motorcycle Mechanics Show in Stafford for the second year running, read the report here.  For next years show I dont want to show the Honda as my main bike (hopefully it still will be there) so all my attention and focus switches to my AF1 as my main show bike.

So the line in the sand will be that it must be ready by October 25 for display at the Stafford show. the countdown starts now....

As it is today 16/10/2024

Jobs to do

Bodywork - already own NOS LH + RH fairing panels, NOS fairing V piece. See here:
Nose fairing is 9/10 its status is TBC pos replacement or paint?
Fuel tank - repainted
Seat Unit - repainted

Decal kit - ebay £110

Front + rear saddles need recovering - ebay, £132 + fitting

Powder coating

Swing arn + rear subframe + misc part

New bolts - stainless steel + alloy

Cleaning and polishing - various parts

Top yoke - possible needs replacing?

Engine - cleaning

There are a few big jobs there, but actually nothing to crazy to get it show ready. My first job is to pull it apart and prioritise jobs, obviously I will blog each step so you can see the process. the dates are not out yet for the 2025 show but I expect it to be the weekend 11th/12th October.

Paint codes - 89 Replica

 I have been looking at getting some panels re-painted so inevitably I've been looking for paint codes. I have unearthed a very useful thread on the Aprilia AF1 125cc page from 2021, for more colours view it here

For the 89 Sintesi Replica it looks like the following are correct:

Red = Rosso Custom JBT2

Lilac = Viola Chiaro JBR8

Turquoise = Turchese JLR4

The 1989 AF1 Reggiani Replica

Did Aprilia release any production Type EU Sintesi bikes with a number 6 on the tail piece (Reggiani) or were all bikes number 4’s (De Radigues)?

On Aprilia's own workshop manual it features the Sintesi version 1 (type EH) and the version 2 (type EU), on closer inspection the type EU features a number 6 on the tail unit like the type EH Reggiani relplica.

Image from the official Aprillia workshop manual

Digging a little deeper the number change happened to reflect the changing of Aprilia's sponsored GP riders and the need to sell was being raced at the time.

Making its debut at the 1988 Bologna Motor Show, Aprilia presented the updated type EU Sintesi Replica 125 motorcycle featuring the number 6 on the seat unit, this was to reflect their then sponsored rider Loris Reggiani who ran that number in 1988 season. However, after finishing 13th in the 88 season Aprilia did not renew the teams contract and the rider switched to Honda. For the 89 season Aprilia replaced Reggiani with the Belgian Didier De Radigues. As the new rider came from the 500cc class to the 250cc class he did not have a race number frpm the previous season so was assigned the race number 4. To reflect their new rider Aprilia changed the tail number from 6 to 4 on the Replica model for production versions, however some bikes were sold as Reggiani '6' bikes in the first few months of 1989 but are extremely rare.

This would also explain why the De Radigues Replica bikes are technically in the 88 Reggiani colours rather than the revised 89 colours as at this point the bikes were probably already made or at the minimum some body panels would of been painted ready for assembly. 

1988 Reggiani race bike

1989 De Radigues race bike

If you have a genuine number 6 type EU please leave a message bellow as I would love to see it!

Many thanks to the contributors of the Aprilia AF1 page on facebook and  125 Stadali

UPDATE 06/11/2023

Taken from Practical Sportsbike magazine July 2016

number 6!

image captured from a video at the 1988 motor show