Morini TT3 400 Race Bikes

 

Mayoreric wrote an article of the Morini 3 1/2 based Junior Race bikes run in the Italian Championships "Up to some years ago, junior racers were allowed to run only on production model or TT Formula bikes. With the aim of participating in the Italian 1981 TT3 championship (4 stroke up to 400 cc. and 2 stroke to 250 cc.), race-bike specialist Bruno Ruozzi from Reggio Emilia decided to produce a bike starting from a damaged Morini 3 1/2, that he had bought for a few hundred thousand lire (a few hundred dollars US). It was a brave decision and it went against the current of the times: the Benelli 2 stroke - 250 cc. twins were dominating the class"

The Riunite sponsored bike above is the bike prepared by Bruno Ruozzi, who, sadly I have read, passed away very recently, and was the winner of the 1984 Italian TT3 championship with Andrea Perisi in the saddle, and second in the same championship in 1985, piloted by the late Eros Manfredini.

"This bike is based on a Morini 250 frame - lighter than the 3 1/2 one - that has been polished by Imerio Vizzani and varnished. The magnesium-alloy swingarm was a second-hand part, and the wheels (on the 400cc. version) are Marvic. The brakes up front are two front 270mm discs with Brembo two piston calipers (they cost much less than the four piston brakes!). Giving extraordinary attention to every detail and doing scrupulous lightening work, the dry weight has been kept at only 102kg"

"The engine, fed by two Dellorto PHBH 32mm. carburettors, has been thoroughly modified around the heads: the inlet ports are now perfectly straight, and the valve seats and upper wall of the combustion chambers are made of bronze parts heat fixed in the heads.

The valve guides have been shifted outwards and this, together with the increased bore to 66 mm, permitted mounting of much larger valves than original. (The inlet valves are 35mm. and the exhaust are 31mm. with just 6 mm. stems). The valve springs (with extra additional smaller internal springs) and rocker arms are original. Regarding the latter, there was a great deal of experimentation with eccentric bushes to change the ratio between the arms.

The camshaft is an L5 provided by Moto Morini. The tappets have been replaced with longer and lighter steel ones, and the pushrods are obtained from a VW Beetle!! The original pistons were replaced with SCIAMs featuring a different crown shape. The compression ratio is now over 12:1. The cylinders now have an integrated silicon carbon-nickel bore. A couple of cast-iron bores from a Renault 5 have also been used as well with very good results. The primary drive is stock but significantly lightened, the flywheel thickness has been more reduced by more than half and the bike has a highly modified clutch and gearbox (ratios are closer). Connecting rods and crankshaft are original but have been lightened and mirror polished. The exhaust ports are hand-polished and have the same length (the right duct is connected to the rear cylinder).

The engine has never been bench tested, but has a surprisingly wide usable range, from about 3000 to 10500 rpm. The maximum power is estimated to be about 50 HP, considering that the bike reaches 215 km/h and turns at the Misano racetrack in about 1'32''.

The late Bruno Ruozzi

1984 Champion Andrea Perisi

The bike above, is the Morini 400 TT3 engineered by Dario Rei and ridden by G.Mazzitelli to second place overall, winner of the TT3 class, in the 1981 championship.

It was powered by a 389cc version of the 3 1/2's V Twin ( Bore 66mm and stroke 57mm) and running a compression ratio of 13:1. Twin Dell'Orto carburetors and a straight tooth primary drive. Also using the 250 frame, in fact the first TT3 to go this route.

The TT3 Morini's are still used as they should be in Classic Motorcycle racing.