J.A.P. Engined Racing Vincents
Having bought the company, Philip Vincent changed the name to 'The Vincent H.R.D. Company Ltd' and proceeded to produce motorcycles to his own design, incorporating among other innovations, a most unusual triangulated sprung frame.

Philip produced his first racing machine almost immediately in 1928, using a 250cc racing J.A.P. engine. He proved its worth at Brooklands coming in sixth in the 200-mile race, at an average speed of 67.58 miles and hour. That year at the Olympia show Vincent exhibited a 500cc racing model, complete with nickel frame and finished in green. It used a propriety 500cc double port racing J.A.P engine, a popular choice at the time (incidentally, a derivative of this engine ruled the roost in speedway racing for over 30 years). This model certainly looked unusual and (as far as I am aware) did not achieve any notable success.

The next year Vincent incorporated a grass track model into the range, at that time a very popular sport, again fitted with a J.A.P. racing engine.Unfortunately, as only 2 were sold it could not be considered a success (e-mail if you've got one, I would love to know if either survived!).
Up until the mid 1930's Vincent's were using proprietary engines, rather than their own. What was suprising was that, although they were using Rudge Python engines in their road bikes (at a time when Rudge were making one of the most successful racing bikes), they were using J.A.P. engines in their racing bikes!

In 1934 Vincent's competed in the Isle of Man TT races for the first time. For this they used a new engine which Teddy Prestwich had assured Phil Vincent would be a sure winner. Unfortunately it was not to be, the engine proved very troublesome, and despite the Vincent teams many efforts to make the engine reliable, both Jack Williams and Arthur Tyler retired, leaving Norton's to claim first, second and fifth.

Meteor and Comet Engine
When Phillip and his team returned from the island they were so tired of J.A.P. engines that work was started on their own design immediately, resulting in both Comet and Meteor models being displayed in time for that year's Olympia Show in October.

So, from 1935 onwards, Vincent racing motorcylces were fitted with their own design of engine and Although they did not win the 1935 TT they did at least manage a reasonable 7th place.
It is worth pointing out though that J.A.P. engined bikes were not totally absent in 1936, indeed the 11th and 13th placed bikes in the Senior TT were such bikes, ridden by Manliffe Barrington and L.Courtney, (see picture).

A customer version of the works racer was displayed that year, the TT Model. This was fitted with a racing version of their Comet engine, fitted with the higher lift 5x cams, bronze head and a Burman 4 speed racing gearbox. A polished stainless steel was an optional extra, costing an extra £1 over the normal price of £98 (see archive pictures). This bike could be supplied in pure racing form or as a super sports road model.

In 1936, like a number of manufacturers at that time, Vincent decided to experiment with supercharging. The works racers at that years Senior TT were fitted with Zoller superchargers, or at least, they were in practice. Two of the 5 Vincent entries were using superchargers, ridden by Jack Williams and Jock Forbes, however, the unsupercharged bike of Jock West lapped quicker, Added to this the supercharged machines were continually overheating (due partly to fuel starvation!) and eventually both riders reverted to unsupercharged machines. That was about the end of it as far as supercharging went, except for postwar specials of course!, however, the fact that they did not work well was probably due as much as anything to them being very much a 'rush job', without receiving the development they needed to be successful.

Series B Racers and Twins
For 1937 the catalogue showed the racing version of the Comet with a new name, the Series B T.T. Replica. This designation was supposedly due to the large number of changes over the previous years model but many of these were subtle and did not change the bikes overall look,
For that year's Senior T.T. a 'works' team was again entered by Phil Vincent but all 3 riders failed to finish. After this, Phil Vincent declined any further involvement with the T.T. races, believing the Isle of Man races had become too specialised to be competative for production based bikes like his own.
In total only five Series B T.T, Replicas were made, and at least one survives.

1936 heralded a major landmark in the history of Vincent motorcycles, with the introduction of the immortal Rapide 1000cc V-Twin, the original 'Snarling Beast'. This bike was based on 2 Meteor top half's mated to a common crankcase, the prototype being mounted in a chassis originally built for Eric Fernihough. From standard this machine was capable of a genuine 100mph+, at a time when these speeds were almost unheard of.
A single racing version of the twin was built, it being ridden in anger at the Donington August Bank Holiday meeting by Ginger Wood. Although the bike was not expected to do well against the other nimbler works bikes, in fact it was able to shatter the lap record, before retiring with clutch failure, the nemesis of pre-war Vincent twins.

That was about it for racing Vincent's pre-war, like most other motorcycle manufacturers, with the outbreak of hostilities production moved away from bikes and more towards helping the war effort. When production restarted, Vincent and Irving were far more concerned about trying to put in production a saleable production tourer, rather than racing bikes, so it was not until 1948 that a production based racer was again listed in the Vincent catalogue.