Tm r1 vs tm r2

Has anyone done any back to back testing between the engines?

Is there any time to gained switching to the R2 or is it just easier to drive?

Would there more time in a new chassis for example?

Out of the box a factory prepped R2 is essentially the same as the R1. Carburetion is going to be a much bigger factor…if you can’t jet it correctly then you won’t extract maximum performance, regardless of how “good” the engine is.

If you’re a top-level driver then you may find time by purchasing an engine from a reputable KZ builder. Otherwise if you’re already on a factory prepped R1 then stick with that and work on chassis setup and driving.


There would be more to gain with putting your money in test sessions and work with what you have if it is decent shape.

I’m rocking a TM 10C, absolutely lovely and I’m having no trouble keep R1 behind. Carb settings is crucial regardless of engine

Agree with what both have said above, in that adequate carburation is a fundamental parameter and no engine will compensate for driving skill acquired through experience.

Nevertheless, and for reference, the R2 was developed to increase power and efficiency at mid rpm when compared to the R1, as seen from the implementation of the insert within the reed pack to move it outboard from the engine. The cylinder diagrams have also been slightly re-designed to accommodate this change and favor the design goal.

The cylinder head has been decoupled from the water jacket entirely (as seen on all engines up until the R1), for better heat transfer and management, along with a reduction of material deformation.

The exhaust pipe dimensions have also been revised, for the design purposes listed above.

I believe geartrain and transmission components to be unchanged between R1 and R2.


As much as I thought! Maybe a tenth or so, easiely wipped out by many other factors. Thanks guys

Stan Pex made third on the podium of the 2023 FIA World Championship, in KZ, against factory drivers, factory chassis and factory R2 engines which are by default the best that exist at that time.

He did that with an R1, tuned in his garage by himself and his dad.

Food for thought :wink:

1 Like