IAME X30 125cc FAQs

What RPM should I be aiming for with my X30?

The optimum RPM at the “average” track is generally around 15400-15800rpm (14800-15500 restricted) at the end of the straight and between 8000-8200 (8200-8500 restricted) rpm at the slowest corner. Depending on the layout of the circuit it may not be always be possible to keep the engine within this RPM range. For example you may find at a circuit that has very tight corners but a long straight may require you to run gearing that causes you to drop below the optimal RPM at the slowest turn and/or possibly run into the limiter at the end of the straight.

What RPM does the rev limiter engage?

The rev limiter engages at 15,800rpm, it is a soft cut limiter and works by retarding the ignition to a point that the engine produces no more power. As it is a soft cut limiter it is not unusual for the engine to rev past the limiter when in a draft or at the end of a long straight when using a high gearing.

What settings should I use for the Tryton Carburettor?
The recommended jet settings for the Tryton carby are 1 hour and 10 minutes on the low and 1 hour on the high, depending on location and climate it may be necessary to deviate slightly from these settings. With a restricted engine it is best to also start with this setting and lean the low jet until the engine runs clean all the way down the straight (Normally around 1 turn out will achieve this). Once the optimal setting is found it is uncommon to have to adjust much, if at all from this setting.

The recommended pop off pressure is 9-12psi depending on location and climate, generally 10psi is a good starting point. With lever height it’s best to start with the bottom of the lever level with the carburettor body, if carby feels to be running out of fuel try raising the lever even more.
What exhaust flex length should I run?
IAME performed extensive testing when developing the X30 engine and as a result the recommended setting of 450mm (65mm flex) is generally spot-on and works best at most tracks. If you are looking to fine tune the engine performance a shorter flex length will give more power higher in the RPM range at the expense of bottom end. Lengthening the flex will achieve the opposite.