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Regretfully, the Irving Vincent Team will not be participating at the Island Classic race meeting in January 2015.


After much communication and several meetings amongst all parties concerned, it has proved impossible to settle on a twin-cylinder engine parity regulation for MA’s Period 5 Post-Classic rules, similar to that prevailing in the FIM World Superbike, Australian Superbike and AMA Superbike championship series. This has resulted in twin-cylinder motorcycles like the Irving Vincent being excessively disadvantaged, to the point that any such bike is incapable of being competitive under current ruling.


The Island Classic’s International Challenge is effectively now Classic Superbike racing, uniquely contested by four-cylinder machinery. The Irving Vincent has for some years been the only twin-cylinder motorcycle able to compete effectively against the four-cylinder machines, with no such entries from marques such as Ducati, BMW, Triumph, Moto Guzzi, etc. Now even we have decided that enough is enough, without any movement in the rules.


A comparison of engine specifications between the Irving Vincent and its four-cylinder Period 5 rivals will confirm the inequity of the present regulations:


Irving Vincent:                       1300 cc

50° Twin Cylinder, Air Cooled

2 Valves per Cylinder

Push Rod valve gear


Honda, Suzuki etc. Fours:     1300 cc

Inline 4 Cylinder, Air Cooled

4 Valves per Cylinder

Twin Overhead Camshafts


This fundamental imbalance between the two types of engine means it is not practical to compete against the 1300cc four-cylinder, four-valve machine with a 1300cc two-cylinder, two-valve pushrod engine. At the stage that we were competing against four-cylinder machines with two valves per cylinder, there was comparable performance. But at the stage that later four-cylinder four-valve engines were admitted – a unilateral decision taken without any comparable adjustment in the twin-cylinder rules – the present imbalance in the regulations took effect, which it seems impossible to correct.


We had requested a two-cylinder 1600cc capacity limit to enable us to take part on something approaching a level playing field, but have been unable to obtain the consensus of all parties concerned to this proposal. As a result, the Irving Vincent team will no longer be taking part in Australian Period 5 competition, unless and until such an unjust imbalance in the regulations is addressed.


We are aware that we will be disappointing our many supporters with this decision, as well as those who welcome the sight and sound of an Australian-built air-cooled V-twin competing against the four-cylinder Japanese machines. We very much regret that this will be the case, but bearing in mind the amount of time, effort and cost that is entailed in competing in these events, not to mention the extreme limits that our rider Beau Beaton must ride the bike at in order to keep up with the 30% more powerful four-cylinder bikes weighing almost the same, we do need this parity alignment in order to be able to run competitively in this form of racing. Without being able to settle on an engine parity ruling similar to that pertaining in National-level and World Superbike racing, we regret having to come to this difficult decision.


Ken Horner

Irving Vincent Race Team

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