Custom Supercharging Yamaha R1 Big Wheels

Custom Supercharging Yamaha R1 Big Wheels,The German tuner RF Biketech has produced a grungy Terminator style homoglogation based on the sleek, sexy, and refined R1. The modification is based on 2006 model year bikes (which come sans a cross plane crank, but with a 1 liter engine with the signature 5 valves per cylinder Yamaha heads, and a 12.4:1 factory static compression ratio). The factory-spec engine already pumps out 180hp (with ram air, and a 172 without) at a rev happy 12,5000 rpms due to the short 53.6mm stroke.

Custom Supercharging Yamaha R1 Big Wheels

Although this is not new news by any means, there are still many of these bikes exchanging hands on the second hand market, and winding up in the hands of enthusiasts looking for project bikes (which is a different market segment from people looking to buy a brand new super sport bike and thus less likely to modify it).
It is a common saying that there is no replacement for displacement, but in fact, the four main contributors to power delivery are: Displacement, RPM, Compression, and Boost. And with the bike already running high compression, and a high rpm redline, then the obvious choice for further power maximization would come from the other two power contributors: namely dispalcement or boost pressure.


Leaving the bottom end on the R1 engine untouched, and retaining the factory displacement of 998cc, RF Biketech have gone ahead and supercharged the motorcycle. By designing a custom take off adapter that connects a rotating pulley assembly to the crank of the R1, they are now able to drive positive pressure into the engine’s combustion chamber via an Eaton roots style supercharger. Working within the original design concept of the R1 with its linear and predictable power delivery, and fairly low RPM redline (compared to other screamer bikes that build power to 18000 rpms) then the choice of the positive displacement Eaton makes a great match for this motor. The Eaton boosts power linearly in all RPM ranges and raises peak power while retaining the tractability of its delivery.

Boost pressure is set at a conservative 0.3 bar (or 4.5psi) of boost which increases power to 230hp @12,500 rpms. [According to the power calculator, a slight reduction of static compression down to 11.7:1 and a 1 step colder spark plug would be ideal for this conversion]. The modifications by RF-Tech also include a custom modified air box with a differently placed ram air scoop, as well as a pre-tuned power commander engine management system for fuel and timing adjustments. A new cat-back exhaust system (with EU emissions approval) rounds out the power modifications and includes a new set of midpipes and rear silencers.
Now that the 1-liter bike performs more like a 1300cc monster, the tuners turn their attention to the integrity and reliability of the drive-train. To increase traction under hard acceleration, the bike has been modified with a 12″ rear rim in place of the factory 10.5″. This allows you to install a wider 360mm tire (up from a 280mm factory tire) for a wider contact patch with the pavement.


In order to fit this size rim on the back of the bike, a new cog spacer is also fabricated, as well as a wider and extended swing arm. The new swing arm has an adjustable mounting position for the rear axle allowing the owner to alter or ‘tune‘ the length of the bike for best compromise between traction (with a longer wheel base) and cornering agility (from a shorter bike with more rapid transitions) and is also available as a single sided wing-arm option (for improved appearance and reduced weight) To keep the bike neutral in handling after the rear tire upgrade, the front tire has also been upgraded with a 5.5″ rim capable of mounting tires up to 180mm wide.

Some may criticize these modifications as affecting the overall agility of the very refined R1. In this case, the tuner has offered all of these modifications as individual packages allowing you to upgrade the power of your R1 without changing the dimensions, the footprint, or the factory handling dynamics of the bike. However, considering that it is now virtually performing as a 1300cc bike in a 1000cc chassis, then you might want to at least consider some stickier tires and a wider rear chain to hold the power. A change in rear gear ratios may also be a good idea to find the best match between torque delivery, traction, and top end acceleration.