Triton motorcycle

The Triton was a modified Café racer motorcycle of the 1960s-1970s. The name derives from a contraction of "Tri"umph and Nor"ton"; the two brands of motorcycle combined.

The intention was to combine the best elements of each to give a superior bike to either. The usual practice was to take the Triumph parallel twin engine and use it to replace the engine on a Norton "featherbed" framed motorcycle that was regarded as the best handling motorcycle of the day. The Triumph Bonnevilles engine that already had twin carburettors was a popular engine choice. This engine, as well as other Triumph twin-cylinder engines, gave good performance and reliability and could be easily tuned for greater power by the addition of high-profile camshafts, high compression pistons and twin carburettors or fuel injectors amongst the more common power contributing modifications. There was also a Weslake 8 valve head available for the Triumph.

The Norton 650 and 750 vertical twin engines had a reliability problem. At about 7000rpm the piston exceeds the engineering limit for piston speed, so over-revvers soon destroyed their engines. The BSA 650 had a bronze bush main bearing on the right hand side, doubling as the crank oil feed, with a lack of effective crankshaft end play control, that all had difficulty staying together when thrashed, even though the rest of the design was possibly better than the Triumph. The Triumph vertical twin used a ball on the timing side, and a roller on the other, with the oil feeding through a separate bronze bush in the outer right hand engine side cover. The Triumph was the pick of the bunch.

Whereas the Norton 650SS 646.44 cc had a bore and stroke of 68 x 89 mm giving 49 bhp @ 6,800 rpm, the Triumph T120 Bonneville 649.31 cc had a bore and stroke of 71 x 82 mm giving 46 bhp @ 6,500 rpm. However the mean piston speed of the Norton was 3,971 ft/min (dangerously close to the then accepted limit of 4,000 ft/min). The Triumph, with its shorter stroke, had a mean piston speed of only 3,497 ft/min, had much less vibration and was much stronger and reliable. Road tests showed that the Norton had a higher top speed due to its 3 bhp advantage. In spite of this, the Triumph was the much preferred engine. The Norton featherbed was the preferred frame. Hence the Triton.

If the Triton used a pre-unit Triumph motor, then the AMC gearbox used in Nortons after 1960 was better than the equivalent Triumph gearbox. There was also the Quaife five speed.

A common choice for the modern day Triton is to use a Triumph unit construction twin in a featherbed frame.

Several motorcycle dealers made equipment for Triton conversions, some would do the complete job for customers while others sold complete Tritons. The most important part required are the engine mounting plates and several different designs exist that can affect the engine placement and therefore the handling. The lower the engine is mounted the better the handling achieved from the Norton frame.

The Tribsa, an alternative to the Triton, was a Triumph engine in a BSA frame but other frame and engine combinations were also made.

Vincent V-twin motors have been fitted into featherbed frames making a hybrid called a "Norvin". [ [http://www.thevincent.com/NorvinTechSection.html Norvin technical section] thevincent.com (retrieved 18 November 2007)] [ [http://www.vintagebike.co.uk/Bike%20Directories/Hybrid%20Bikes/pages/Norvin-2.htm Norvin "Spirit of the Sixties 2"] VintageBike.co.uk (retrieved 17 November 2007)]

References

External links

* [http://www.ace-cafe-london.com/f2_2.htm Ace Cafe, London] Cafe Racer
* [http://www.supernaturale.com/articles.html?id=79 Building a Triton in your kitchen]
* [http://www.realclassic.co.uk/triton04120100.html Realclassic 1959 T100 Triton]
* [http://www.inventivestudios.co.uk/thebikeshed/55triton.html the Bike Shed's 1955 Triton]
* [http://www.egge.net/~savory/triton.htm The 1960s Dream Machine]
* [http://www.dresda.co.uk Dresda Autos] Triton Builders
* [http://caferacersreturn.blogspot.com Return of the Cafe Racers]