Aermacchi IHRO1 Machine Specifications


Filed Under (Aermacchi) by admin on 13-11-2010

1. IHRO 1 caters for single cylinder thoroughbred Grand Prix racing motorcycles constructed during the period 1945-1972 inclusive, for the specific purpose of participation in Grand Prix competition during that era. Maximum capacity for any machine is 500cc, and wherever possible it is intended to run three classes, for machines up to 250cc, 350cc and 500cc. 2. Motorcycles must be presented in original, period condition, with no external updating. Period appearance seats, fuel tanks and fairings (if fitted) must be used. No external changes may be made to the appearance of any machine unless it can be proved that such a change was made in the period. Modern safety fixtures required by some federations and modifications mentioned in this document are not covered by this ruling. 3. No disc brakes are allowed. Drum brakes only may be used. 4. No alloy/magnesium wheels are allowed. Wire wheels only may be used. 5. All machines must have twin shock rear suspension: No monoshocks except Vincent Grey Flash. Suspension units must resemble period components, i.e. no external gas reservoirs etc. 6. All frames and swinging arms must conform exactly to period appearance; no box section swinging arms allowed unless fitted by the manufacturer to that machine in the period. 7. The maximum permitted rim width on either wheel is WM3. 8. No slick tyres, hand cut slicks or modern racing tyres designated by the manufacturer as being exclusively for wet weather use are permitted. Only the following rear tyres may be fitted. Any 19″ tyre. The following 18″ tyres, Dunlop 3.50×18, 3.50/3.25×18 KR124 and KR124A, Avon AM22 110/80×18 Rear Fitment and Avon AM18 120×18 9. Choice of carburettor is free, provided that this is of a period type cylindrical slide model, albeit of a later manufacture. Flat slide instruments are not permitted with the exception of Gardner carburettors. Fuel injection is not permitted except if it can be proved that particular motorcycle ran between 1945-72 with the same type of injection system fitted. A Wal Philips injector is classified under this heading. 10. The type of fuel used must conform to the ACU and FIM’s current fuel regulations for 100LL Avgas at 102 MON. See full specifications below. All machines must finish a race with a minimum of 2 litres of fuel in the tank to allow a sample to be taken for analysis. 11. The use of belt primary drives is encouraged.

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