Choose the language.
Tkart magazine

Under Review | Tm racing kz-r1: the 2019 world champion kart shifter engine

go down go up

TM RACING KZ-R1: 2019 WORLD CHAMPIONS












2T

TYPE
2-stroke engine like most kart engines on the market. 4-stroke engines are still a small niche

125 cc

DISPLACEMENT
In karting, gearbox engines have always been 125 cc.

PUSH

START
The usual one, push-start with manually controlled clutch and start in second gear.

GEARBOX

TRANSMISSION
There are two “big families” of engines for karting: single speed and gear. The KZ-R1 is 6-speed.

KZ 2019-2021

HOMOLOGATION
It is the shifter KZ, valid from 2019 to 2021.

The KZ-R1 engine is the new TM Racing’s “weapon” dedicated to the gearbox category, introduced during the 2019-2021 homologation season. Compared to its multi-titled KZ-10C predecessor, this enhanced model has numerous revolutionary changes and refinements which modernizes an already award-winning design, proving once more TM Racing’s ability to remain firmly at the top of this category.

The KZ-R1 analyzed in this article is in the special Red Titan Edition, designed exactly to celebrate the victory of the KZ World Championship conquered by the Dutch driver Marijn Kremers of Birel ART at the South Garda Karting Circuit in Lonato, Italy. However, the aesthetic details that characterize it, such as the anodized aluminum engine plating and the black cylinder head are only the appetizers compared to the numerous new features hidden inside: a long series of improvements designed to increase the reliability and functionality of an engine which, at first glance, is more compact and highly indorsed by the TM technicians, as being much lighter. In this sense, the change that most immediately catches the eye is the reduction of the inter-axis between the various shafts, in particular those between the crankshaft and the gearboxes primary shaft, which is responsible for much of the reduction in size of the entire engine as a whole making it more compact.

0%

    The head of the KZ-R1 is identical to that of the KZ-10C, already equipped with a two-piece version

    read more

    The cylinder is structurally identical to the previous version, also in the cooling ducts while the ports have been modified as well

    read more

    The piston’s weight reduction is not achieved through the removal of material but is rather the result of the casting mold itself being modified

    read more

    The crankcase cover on the clutch side is much smaller than that of the KZ-10C, yet it retained the ribs which increase the resistance to the stresses caused by the machining process

    read more

    The connecting rod is opaque due to the sandblasting treatment, then implemented by a specialized company according to TM specifications

    read more

    To ensure that the reduction of the primary wheelbase did not create additional problems, the engineers also worked on the dimensions of the cooling circuit and, more specifically, on the section where the fluid goes through once it enters the engine, located between the crankcase and the transmission assembly. Here, the shape of the conduit near the fluid input and output point has been revised to compensate for the narrowing that has been created, where the walls of the gearbox and those of the crank chamber almost touch each other. The fluid, as it flows through this gap, must attempt to transmit as little heat as possible, otherwise there is the risk that the mixture will heat up too much before entering the combustion chamber. For the same reason, the lower part of this amount, at the entry point of the fluid, is now exposed more to the airflow, as this is seen by opening the crankcase.

    Continue reading your article

    Don’t waste time: register now for a 24-hour free trial period. Unlimited articles.

    Start your 24-hour free tour
    No Credit Card required
    or
    Skip the free tour and become a TKART Magazine member now.
    • Constant updates
    • Interactive content (360°, Video, Gallery, etc.)
    • 15 sections
    • Over 500 in-depth articles
    • Access to the entire archive
    • Available in Italian, English and Spanish
    • Access from your desktop and mobile devices
    Subscribe