Chemicals and More


Basic  information and guides on your TM Racing machines engine oils,  quantities and oil change routines, fuel and fueling systems, electrical  components and devices and some ‘need-to-know’ maintenance for 4-stroke  engines.

2-Stroke Engine Machines.

Fuel required:-

Super Unleaded – minimum 97 octane.

Premix Oil Ratios:-

Synthetic racing premix oil mixed at 32:1- 40:1 = (this equates to 500ml – 600ml of oil added to 20 Liters of fresh fuel )

Spark Plug Designation:-

85cc / 125cc / 144cc engines require an NGK BR9 EG spark plug. NOTE  2013 onward 85cc Machines require an NGK BR9ECMIX spark plug  –

NOTE: it is advised, in light of some issues over the past few years  with various manufacturers and models with tip attachment failures, that  125cc and 144cc be updated to an NGK R7376-9 plug (NGK stock code 7763)  that features a differing grounding. It is advised to fit this plug  after the running in process has been completed.

Electrode gap = 0.7mm.

250cc / 300cc engines require an NGK BR8 EG plug.

Electrode gap = 0.7mm.

Gearbox Oil:-

80w0r 85W gearbox oil designed for ‘wet clutch’ use or an Automatic Transmission Fluid (ATF). We recommend Spectro 85W Gear Oil

Gearbox oil quantities required are:

85cc/125cc/144cc = 500ml >2006 / 600ml 2007>

250cc/300cc = 650/700 ml.


Keihin PWK / PWM carburetors.

In normal operating circumstances the only changes needed to be made  to your TM Racing 2-Stroke powered machines carburetor will be  alterations to your main jet and your needle clip position, rarely your  fuel/air mixture once set correctly, dependent on track conditions and  operating temperature, please refer to your TM Racing dealer for more  information regarding ‘jetting’ your TM Racing machine before proceeding  with altering any of these settings, your TM dealer can explain to you  the benefits of correct jetting and how to ‘read’ what your engine and  spark plug color is telling you to do.

WARNING: correct jetting will allow your TM Racing engine to perform  at its best in the conditions required, however, do not attempt to  alter these settings with little knowledge or understanding of how these  changes affect the behavior of your engine and the consequences that  these changes can lead to. Making an error in carburetor settings will  cause severe damage to your engine, If unsure contact your TM Racing  dealer or TM UK.

NOTE: on 2-Stroke Enduro machines which normally operate with a  ‘tick-over’ it may ensure cleaner running of you TM Racing machine if  you decrese the pilot jet size to compensate for the increase in  fuel/air at low rpm’s. The idle speed screw on the Keihin PWK/PWM  carburetor is effectively just a device to lift the ‘slide’, therefore  the ‘throttle’ is being held open by the idle  adjuster screw,  essentially you are running on part throttle even when you have the  throttle closed, this can lead to the symptoms of ‘rich’ running at low  rpm’s and can cause hesitancy (bog) from the engine, decreasing the  pilot jet size from 42 down to 40 or 38 will counteract this effect and  the bike will run correctly. Remember always keep the the carburetor  clean and drain after washing to ensure no moisture is trapped inside,  moisture can lead to bad running and corrosion of the internal  components.

4-Stroke Engine Machines.

Fuel Required:-

Super Unleaded – minimum 97 octane.

Spark Plug Designation:-

250cc / 400cc / 450cc / 530cc / 660cc.

NGK CR8 E – Electrode gap 0.7mm.

250cc Fuel Injected Machines – NGK ROO45J-10

450xx Fuel Injected Machines – NGK CR9 EIX

Battery for Electric Start Equipped Machines:-

Yuasa YTX7L-BS

Engine Oil:-

Running-in period = High quality semi synthetic 20w/50 racing motorcycle oil for use with ‘wet clutches’.

Post running-in period = High quality semi/fully synthetic 20w/50 racing motorcycle oil for use with ‘wet clutches’.

Engine oil quantities are:-

250cc / 400cc / 450cc / 530cc :-

Oil change = 1.300 liters.

Oil and oil filter change = 1.350 liters.

Complete rebuild = 1.400 liters.

250cc Fi models:-

Oil change = 1.200 liters.

Oil and oil filter change = 1.250 liters.

Complete rebuild = 1.300 liters.

NOTE: Whilst completing oil changes on your TM Racing 4-Stroke  machine you must ensure that the oil level in the inspection window is  always visible before and during engine running. Ideally the oil level  should be showing as 3/4’s full in the inspection window at idle, upon  increasing the engine rpm’s the oil level should lower slightly as the  oil pump increases its flow rate around the engine, once the engine has  settled back to idle the oil level should return back to 3/4’s full in  the window, If not please add more oil until the desired measurement is  achieved or slightly exceeded. Warning: due to the position of the sight  glass it is possible for an air pocket to occur in the top of the sight  glass, this can lead to a false reading and the oil level could be  higher than suggested, please take care when filling to ensure you do  not overfill or under fill. Please refer to your TM Racing user manual  for more information.

Valve Clearances

250cc / 400cc / 450cc / 530cc / 660cc  =

Inlet 0.10mm >  0.15mm -/- Exhaust 0.15mm < 0.20mm

250cc Fi =

Inlet 0.10mm > 0.15mm mm  -/- Exhaust 0.15mm > 0.20mm


Mikuni TDMR 36/39//41 – Keihin FCRD 39/41

As with the two stroke machines the carburetor settings should need  little adjustment, the carburetors used on TM Racing 4-Stroke machines  are very complex and should not be tampered with by inexperienced users,  please refer to you TM Racing dealer for more information on these  carburetors and for any technical help you may require with any running  errors of the fuelling system. Remember always keep your carburetor  clean and drain it after washing to ensure no moisture is trapped  inside, this can lead to bad running and corrosion of the internal  components.

Electronic Fuel Injection Systems.

Electronically Fuel injected machines require little in the way of  maintenance and set-up, on TM Racing EFI equipped machines the fuel is  filtered upon entering the fuel pump, to remove any impurities or  particles in the fuel, the fuel is then pumped under high pressure  through yet another finer filtration system to the main fuel line into  the throttle body and then into the injector, the injector then atomizes  the fuel into the oncoming air stream and enters the combustion  chamber. The metering and volume of fuel injected into the engine is  controlled by the ECU which ‘pulses’ and times the delivery of the fuel  supply, the ECU monitors throttle position, engine speed, cooling system  temperature, air pressure, air speed and a number of other factors to  calculate how much fuel is required at any given time, this metering  system can adjust itself to one of its set parameters in fractions of a  second and is a far more economical approach to engine fueling, whilst  not only regulating the fuel supply more economically further reductions  in fuel usage are also gained from not having a ‘float chamber’ like a  carburetor from which fuel can escape through the venting system.

The main advantage of Electronic Fuel Injection system, from a riders  perspective, is that the electronic control of the fuel supply  eliminates hesitation (bogging) that is commonly found in carburetor  4-Stroke machines and also the risk of engine stalling is lessened  (although this is electronically monitored for safety) due to the  electronics ability to alter the fueling characteristics of the engine  and keep it running. A conventional ‘mechanical’ carburetor with a  ‘float bowl’ will lose its fuel from its vent pipes and its fueling  characteristics will change as it cannot utilize its carburetor jets  unless they are bathed in fuel, this then leads to engine stall and  increases the difficulty of re-starting the machine under high  temperatures.

TM Racing’s policy of ensuring only the best components are used on  their machines limits the use for changes to the Electronic Fuel  Injection system, with components of exceptional quality, HGS exhaust  systems for example, being fitted to the machine as a ‘standard’ part  there is no need to ‘upgrade’ components like many other manufacturers  machines and alter the working components of the engine, therefore  altering the components that are factored in the metering devices of the  ECU. The ECU fitted to TM Racing machines is adaptable to a very small  degree and will compensate for minuscule changes to the machines working  characteristics without the need for program interfacing (re-mapping),  this occurs by the ECU using the readings from the onboard sensors and  correcting the fuel supply to a level which it calculates to be closer  to the optimum setting. Whilst this type of system can overcome very  small changes from the stock parameters it is not infinitely calculating  or self intelligent, the parameters it can change to are determined by  the TM Racing programming and the ECU is limited to those tiny  adjustments only, huge changes in elevation and oxygen reduction for  example will be too great for the system to overcome with the  pre-installed parameters and re-mapping of the ECU will need to take  place, however, in the real world these extreme examples are not likely  to occur and the need to interface with the ECU is not necessary or  recommended.

If any problems occur with your TM Racing EFI equipped machine it  should be taken to your TM Racing dealer for inspection and diagnostic  test immediately.

WARNING: TM Racing does not advise alterations to the Electronic  Fuel Injection system, its components or the pre-installed ECU  parameters. This electronic device has been pre-programmed by TM Racing  to give your TM Racing machine the maximum performance, reliability and  safety, Failure to adhere to this warning could lead to engine component  failure and/or injury.