Category: Sven’s Chimera 250 (1963)

text

text

I finished with restoring the seat frame. I replaced every single spring with a new one. I also shortend them to fit exactly to their position in the frame. This took more time then someone might think. The seat together with the kneepads for the tanks will go to a professional saddler to recover them.

I also progressed on the rear wheel and removed the ball bearings which are two FAG standard size “6302” with open cage.

I have designed a spring compressor that fits the Chimera monoshock and printed it in PETG on my 3D-Printer. I wasn’t sure if it will work but the material proofed to be strong enough and it worked very good.

All parts of the seat brackets as well as the kneepads for the gas tank are now freshly powder coated.

text

text

text

Front tire: Pirelli 2.75 -17
Rear tire: Pirelli  MT53 3.00-17
Rims are marked: M. Baruzzo – Torino
Beside “M. Baruzzo – Torino” there is no other markings on the rim, but both rims are 2 1/4 x 17″ for 36 spokes. 2 1/4 translates to modern size WM1 = 1.60
Front spokes: Length: 138,5 mm, diameter  3/3,35-40 threadt/1″ plus 36 nipples
Rear spokes: 142 mm, diameter 3/3,35-40 threadt/1″ plus 36 nipples

text

The muffler is beyond a reasonable repair. The exhaust could be repaird, but replacing it as well seams to be the better choice at this point.

My first set of reproduction dealer stickers for the fenders. They turned out great, but are not metal effect as the original ones.

I have disassembled the seat which will get new paint and new springs. I am already experimenting with available new springs as a replacement.
The carburator is a Dell’Orto UB 22 BS2 and it seems like it was painted black back in it’s days.

Most of the winter time I was hibernating, but it’s time to progress with the bike. I dismounted the cushions from the gas tank and the seat as well. The other pictures are showing excessive rust on the wheels and the rear brake switch. I also made up my mind update the grey color used on my Chimera and decided that it’s not my most favorite one for this particular bike. I will probably restore it to the original coral red (rosso corallo AER A12, Lechler) and sand color (avorio antico AER A11, Lechler) combination of earlier production years.

I tookoff the large gas tank which is one large part together with the rear fender. I also dismounted most of the panels and streamlined fairing parts around the engine and the rear end of the motorcycle. Interstingly it wasn’t a big problem to get a new gas cap as it was used on other italian bikes as well. Luckily, I found a very rare NOS CEV rear light already.
I also started working on a template of the dealer sticker which can be found on the rear fender and also on the front fender.

I removed some of the panels and trims to have a look at the engine, carb and other stuff like the monoschock. Everything looks very rusty, but otherwise in good original condition. I connected a 6V battery, but there was no spark.

The first impression after having the bike at home was still very good. Almost everything is there. Nothing seems to be altered or repaired incompetent. An emblem on the dampener knob is missing, the tail light is broken, but I didn’t find unexpected surprises.
A dealer decal at the front and rear fender says “Officina Riparazoni Auto Moto Aermacchi Harley-Davidson Cycles F.LLI DELFINO via Carlo Marx Tel. 62906, Alessandria”.

Totally unexpected I have a new Aermacchi restoration project! Accidentally I saw a sales ad for an Aermacchi Chimera which went online just five minutes before I discoverd it and the bike was also located in Germany. This alone does not happen very often, but the price was good as well. I called the seller then everything happend very quickly. Two days later I was driving 500 kilometers north through Germany to get the bike and instantly another 500 kilometers back with the Chimera on the trailer.

What I do know so far: The bike was running until 1986 in Italy. It has 31.000 kilometers on the odometer and was imported to Germany in 1989.  Obivsously it was kept in private motorcycle collection since then.
This is a 250cc Chimera. The exact model year is unclear at the moment The decals suggest that it is a model between May 1960 and 1963 as it already reads “Aermacchi Harley-Davidson. According to A.R.S.I.M.A the bike is in an overall original and complete condition and the grey color was experimental by factroy to show dealers new color options”. I am very happy about the condition, even both steering lock keys are there. I do not know if the engine might work, but the bike shifts and the piston is free. Engine and frame VIN are original and matching. I got an import certificate with the bike and a bill of sale.

What makes the Chimera special?

The Chimera is the ancestor of all the Aermacchi four-stroke bikes. The engine was developed especially for the Chimera by engineer Alfredo Bianchi. This new OHV motor with almost horizontal Cylinder was also used in later Aermacchi 175cc and 250cc models like Ala Rossa and Ala Verde and it was also the Basis for some sucessful Aermacchi racing bikes like the Ala d’Oro. The engine was later redeveloped as 350cc motor and in 1973 it got equipped with an electric-starter-motor until model year 1974 when AMF Harley-Davidson decided to stop the production of the italian four-stroke bikes in 1973.

Designer Mario Revelli di Beaumont was contracted in 1956 by Aermacchi to design this new four-stroke motorcycle. He was an experienced designer and also a motorcycle race driver who was already involved in designing some famous Fiat cars. In the 1930 he also worked for Pininfarina. Revelli got free hands designing the Chimera. He decided for the futuristic enclosed engine housing in a “turbine desgin” and a uncommen gas tank which is one piece together with the rear fender to show Aermacchis ancestry as aircraft maker. The bike was unveiled at the milan motorcycle fair in Dezember 1956.

The Chimera is also one of the first motorcycles in the world where allen screws had been used. Parts of the body are aluminum cast and fit very precisely to avoid vibration noises. The engine side-covers themselves are part of the Chimera line and and made to fit perfectly into the design. The bike is as well equipped with a telescopic Upside-Down front fork and a monoshock rear suspension to not disturb the elegant linie of the bike.

Beside all the effort and money that was put into the project the Chimera didn’t sell well. Aermacchi tried to boost the sales by upgrading the bike from 175cc to 250cc in 1958, but this did not bring the success they had hoped for. The production of the Chimera ended in 1964 with only 119 documented 175cc bikes and another 177 Chimeras with 250cc bore. However some more bikes had obvisouly been built, but there is no documentation about it today.