Yerf Dog Spiderbox & Crossfire Internal Reverse Engine Upgrade Package, 150cc, 175cc, 184cc

  • $849.00
    Unit price per 

Finally you can step up your Yerf Dog or yellow Crossfire to be like all up to date buggies.  We have developed a bolt-in package for a reverse engine for your Yerf Dog Spiderbox. or yellow Crossfire  This is the standard GY6 internal reverse engine that comes on all new buggies.  With this package you get:

  • The GY6 internal reverse engine
  • A reverse shifting package to change from forward to reverse.
  • Machining and welding of your axle.

This is a standard GY6150cc engine.  However, you can upgrade to a 175cc or 184cc racing engine. 

The shifting package included two shifting cables, shift handle and other hardware to change gears.

In order to get your axle sprocket to line up with the engine sprocket, you'll send us your axle and we will cut the weld on your axle and move the sprocket hub location over and re-weld.  

If you select the 175cc or 184cc engine they come standard with the upgraded transmission with the 1500RPM yellow spring, the high stall clutch and the performance variator.


If you are considering purchasing a GY6 engine from eBay, Amazon or any other USA seller you could receive a 125cc engine instead of a 150cc and you would never know it.  The engines look identical from the outside.  BDX Performance is the only engine seller in the USA who disassembles and visually inspects engines to ensure that they are 150cc.  We unbox and dissemble approximately 50% of every engine shipment that we receive as we convert these into 175cc engines.  And we have caught some engines that are GY6 125cc being sold as GY6 150cc.  Don't play Russian roulette with your money.  Get a guaranteed, verified and certified GY6 engine from BDX.  The cylinder on the left is an actual cylinder that we pulled off of an engine that we purchased as a 57mm GY6 150cc engine and was actually a 52mm GY6 125cc engine.