Yerf Dog Spiderbox & Crossfire Internal Reverse Engine Upgrade Package, 150cc, 175cc, 184cc
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 GY6 reverse engine for your Yerf Dog Spiderbox. or yellow Crossfire This is the GY6 internal reverse engine that comes on all new buggies. With this engine you will need the modifications defined below.
YOU HAVE THREE ENGINE OPTIONS
Engine 1: 150cc Standard stock GY6 Engine with Internal Reverse with stock transmission--GUARANTEED DIRECT FIT with the defined modifications below. You can get this engine with a high performance transmission installed and get more torque and power to your wheels.
Engine 2: 175cc GY6 Racing Engine with Internal Reverse and stock transmission--GUARANTEED DIRECT FIT with the defined modifications below. This engine comes with the 62mm big bore cylinder and piston kit pictured below installed in a bored out case. We strongly recommend the BDX performance transmission for performance engines--Click here to see why.
- Engine 3: 184cc GY6 Racing Engine with Internal Reverse and stock transmission--GUARANTEED DIRECT FIT with the defined modifications below. This engine comes with the 62mm big bore cylinder and piston kit pictured below installed in a bored out case and a 3.0mm high performance stroker crank. Call regarding this option. We strongly recommend the BDX performance transmission for performance engines--Click here to see why.
MODIFICATIONS: In order for this engine to work on your Yerf Dog Spiderbox you will need the following:
Yerf Dog Spiderbox Heavyduty Refurb Axle Kit: Your axle sprocket is in the wrong location and cannot space over the sprocket in that direction without lathing and re-welding the hub. If you have the ability to lathe and reweld your axle then you do not need this kit. This heavy duty axle also fixes the Yerf Dog Spiderbox breaking axle problem.
Reverse Shifting Kit: This kit allow you to shift from forward to reverse.
- BDX Adjustable Chain Tensioner: This chain tensioner is needed to mount the rear of your new engine to your swing arm.
YOU HAVE POWER PERFORMANCE OPTIONS
Option 4: 11 Pole Stator, rectifier and harness adapter. With this option you get more power to run your lights and other accessories. If you get this option it will be installed and tested in your engine--Click Here. The engine comes stock with an 8 pole stator. A few small number of vehicles require an 11 pole stator. Call before ordering if you.
Option 5: Performance Exhaust: You can get the BDX performance exhaust for any of the engines above for an estimated 10% to 15% increase in raw power--see video!. Your stock exhaust is restricting your power because the exhaust gases are being squeezed out through a tiny hole. The BDX Performance Exhaust fixes that. If you get a performance engine without the performance exhaust you will be restricting some of that NEW power. To see details or add the exhaust to your order click here. Or see our video to see what this increased horsepower looks like in a race click here.
THE BDX PERFORMANCE TEAM MEMBERS ARE THE GY6 ENGINE EXPERTS IN THE USA. BUILDING AND SHIPPING HUNDREDS OF GY6 PERFORMANCE RACING ENGINES FOR OVER 10 YEARS. WE HAVE A FULL MACHINE SHOP IN VIRGINIA WITH AN ENGINE TECHNICIAN AND ENGINEER. SEE VIDEO
READ ARTICLE ON HOW DISPLACEMENT RELATES TO MORE POWER.
HOW BIG BORE KITS & STROKERS WORK
TAKE A LOOK AT THIS COMPARISON
Stock GY6 Engine
BDX Performance Racing Engine
WE BUILD AND TEST OUR 175CC RACING ENGINE IN OUR FACILITY IN VIRGINIA.
We disassemble your 150cc engine, bore the case to make it larger so that we can install a 62mm big bore piston and cylinder. Then we re-assemble and test your engine.
BORING THE CASE FOR THE 62MM CYLINDER AND PISTON
62MM 175CC BIG BORE KIT
BE SURE TO READ THE ARTICLE ON HOW DISPLACEMENT AFFECTS YOUR POWER.
12 Month Warranty with Purchase of Uni-Filter
Please read the Warranty details in warranty section
Engine is shipped DRY with no oil.
Be sure to add 750ml of 10w40 to the crankcase and fill gearcase to the fill hole with 80w90 to the before starting. There should already be gear oil in the gearcase but it is always safe to check.
Adjust valves after break-in period.
Change oil after break-in period.
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.
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.