Categories: Product Information

NOTICE: Kawasaki Ninja H2 Overdrive Supercharger Gears

NOTICE: Kawasaki Ninja H2 Overdrive Supercharger Gears

Here at Brock’s Performance, we have recently been confronted with questions in regard to the installation of aftermarket overdrive supercharger gears. While Brock’s Performance had no input in the design or manufacturing of these gears, as a customer courtesy, we would like to relay our concerns as to why we believe a product like this should be professionally installed and accompanied by a professional tune and technical support.

  1. The H2 may not have enough fuel pump volume for sustained high speed use when the boost is increased. For this assessment, we look to the Ninja H2R having 50% more fuel pump volume. Adding additional boost will tax the H2’s fuel system even more.
  2. When boost pressure is increased, ignition timing should be decreased. The big question is… how much? Your builder/tuner can help you with this. CAUTION: Brock’s Performance DOES NOT recommend the use of overdrive gears with our Stage 2 ECU Flash as delivered.
  3. Insufficient Octane. With additional boost, comes higher inlet temps… will 91-93 Octane be enough? We honestly don’t know, and it will depend on your use. If #1 and #2 above are handled accordingly – maybe? Or, you might need to tune to a race fuel only situation (or E85–aftermarket pump a must.)
  4. Higher Boost Temps. Kawasaki designed the H2 for use without an intercooler. BUT, more boost = higher inlet temps. Aftermarket intercoolers are available; see your builder or tuner.
  5. Maintenance intervals. How many H2 owners, that have increased their rev limiter to H2R levels, have paid attention to the accelerated maintenance schedule? For those who may not be familiar, please click here. Increasing power/boost levels, without knowing that your engine/valve train is in good shape, is never a good idea for longevity. In most cases, higher valve spring pressures and lower compression levels are used – or intercoolers and high octane fuel. Speak to your builder or tuner.
  6. Gear fitment. Based on our inspection, the aftermarket gears exhibit a slightly lower class fit than OEM (a bit on the “loose” side, comparatively), this in itself is not extreme but we are concerned that this could lead to the mounting bolts prematurely loosening during operation – following the service manual precisely, combined with extreme care and proper assembly techniques might be able to circumvent this potential problem.

Does the above mean the gears are not useable? Certainly not. In the hands of the right person, the benefits from a product like this could be significant. Does it mean they are not ‘drop-in’ parts? Most certainly. Brock’s Performance is in the drop-in business, and as such, we have no plans to sell or support the tuning/use of these gears.

Contact the distributor or mfg. of your gears for more detailed information relating to the items noted above.



Have questions about Brock’s Performance products? Contact our Sales Specialist today at 937-912-0054 or


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