BDX Gy6 Stage 2 Performance Roller Weights Transmission Upgrade

In stock
Regular price $49.99

BDX GY6 Stage 2 Performance Transmission Upgrade


Fits any gy6 150cc to 184cc engine

  • 150cc
  • 170cc (YES, this fits the K-block 170cc engines)
  • 175cc
  • 184cc

Does not fit K-block 177cc engine


We sell different stage transmission upgrade kits! This is Stage 1, Stage 2 includes a 1500rpm spring and then our final upgrade is bit of a jump but you get our Powerpak which includes every upgrade possible for the transmission and overall performance.


BDX Part Info:

1500rpm "Contra" Spring:

The contra spring provides the downshifting forces in a CVT transmission by working against the roller weights. CVT tuning is all about balancing the roller weights with a proper contra spring. The 1500RPM spring increases the tension on the belt and rollers. This delays the transmission from upshifting too soon and also reduces belt slippage. The 1500RPM spring itself increases and smooths out acceleration, low-end grunt, and maximizes backshift. "Backshift" is the delay time it takes the transmission to downshift when engine RPMs drop. This is best visualized when thinking about coming in and out of a tight turn. Slowing for the turn the RPMs drop, you then clear the turn and apply full throttle. This is where backshift plays in -- you want the transmission to downshift to the proper lower gearing ratio as soon as possible through the turn so the CVT won't be stuck in an upshifted state when throttle is reapplied coming out of the turn.

Roller/Slider Weights:

Changing out the rollers is undoubtedly the best bang-for-the-buck upgrade there is for your buggy. Roller weights provide the upshifting forces for the CVT transmission by flinging outwards within the variator in varying stages of engine speed (RPM). Roller weight tuning is a matter of preference and riding terrain. A lighter weight will fling outward slower than a heavier weight, slowing the upshift process, and keeping the transmission in low gear longer. The stock 14.5g weights are rather heavy and upshift very fast in the RPM cycle, resulting in hindered acceleration and limited low-end grunt. These are our notes regarding tuning and roller weights.