Specializing in Heavy Duty and Performance Parts

Important Engine Information


  • Adjust valves after break-in period.
  • Change oil after break-in period of one one to two tanks of gas depending on the size of your tank.
  • Engine is shipped DRY with no oil. Be sure to add 750ml of 10w40 to the crankcase and 120ml of 80w90 to the gearcase before starting.
  • Do not use synthetic oil in GY6 engines until after the break-in period.
  • Install a uni-filter with new engine for longer life and better performance.  If you don't you are guaranteed to be putting dirt into your clean NEW engine.  Stock Chinese air filters do not effective filter air and are the number one engine killer for GY6 engines.

Your Warranty is void if you do not follow the instructions below:

  • Do NOT exceed 60% of full throttle for a one hour break-in period of 1 to 2 gas tanks.  Vary your speed during the break-in so that the engine sees a variety of conditions and helps break it in for a broader range of operation. 
  • Check all vent hoses.  Some engines have plugs and some have the vent hoses taped shut to prevent oil leaks during shipping.  Remove all plugs or taped hoses to prevent from blowing out your cylinder gaskets.
  • Our warranty is void if you do NOT use a uni-filter with this engine.  GY6 stock air filters are notorious for allowing dust and debris into the engine and requiring a rebuild in a few months. 
  • Modify your engine without first contacting us and us agreeing the the changes that you are making.

Save Your Box
In the event that you need to send your engine back to us for a warranty issue or another reason save your box.  GY6 engine damage is a huge problem and if you ship without using the box that we shipped to you are almost guaranteed to get engine damage,  Thus we have a no box no warranty policy.

Guaranteed Fit - No returns on engines.
Before ordering please call and speak to our technician if you have any questions regarding fitment.  Please do not return your engine--call us if you ordered the wrong engine without consulting our technician. In the very rare event that there is a warranty issue please see warranty section.

About Oil Coolers:
Our engines Do NOT come with provisions for oil coolers. We've always advised strongly against the use of oil coolers on the GY6. We've seen too many instances where a cooler line bolt vibrated loose, dumping all of the engine oil and causing a massive failure.  The perceived benefit isn't worth the risk. Oil coolers on the GY6 solve a problem that doesn't exist. Follow regular maintenance intervals, invest in a UNI Air filter (and keep it oiled), and your new engine will last many years even decades--we've seen it many times. Coolers provide a false sense of longevity benefits, and the only proven result is the added risk of unexpected massive failure.

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. Since 2006 China has a history of sending 125cc GY6 engines in place of 150cc GY6 engines. 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--see below. 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 a China engine that we purchased as a 57mm GY6 150cc engine and was actually a 52mm GY6 125cc engine.