SkyHawk 66cc Gt5A-ES ENGINE - plus GOODIES & Free Shipping

Grubee Inc


SkyHawk Gt5A-ES easy start engine plus goodies  


 Includes: SkyHawk Gt5A-ES 66cc engine $129.00 value.

 Includes:   HP TZ CDI red wire ignition: $18.00 value

 Includes:   7 pcs front mount shim kit:  $12.95 valve 

 Includes:  USPS PRIORITY SHIPPING:    $22.00 value  

 Includes:   3 Pt electrode spark plug.      $5.00 value 

 Includes:   46cm long rubber fuel line.  $ 8.00 value  

Includes:    Fuel line filter                          $3.00 value                                                                           $198.00

Notice:   We no longer sell on eBay or AMAZON. 

ENGINE DETAILS:   66cc /  2.7HP  47mm X 38mm BORE AND STROKE:  It's said by many folks to be the most powerful stock high rev 66cc 2 stroke bike engine ever made; 

The 38mm short stroke can rev somewhat quicker than a longer 40mm stroke.    It's the small block 350 Chevy so to speak of the bike engines.    

The Gt5A 66cc Cylinder has a round exhaust port that mates to a round exhaust header pipe for more smoother exhaust flow.  Obviously, oblong rectangular exhaust ports do not match round pipes!   Go Figure! 

SkyHawk Gt5A-ES > Easy Start Engine with TZ CDI Ignition and OCDT starting capability;     

Completely assembled and run tested;   

  • Pedal start or hand held Electric start.

  • CCW threaded crankshaft is the secret that allows electric starting via OCDT, ( Over-running Clutch Drive Tool, order separately if wanted.).

  •  OCDT is not included.  It's an $39.95 extra cost item.  For more details see our OCDT individual add listing. 

  • These are our latest engines with the powerful TZ  magneto system as opposed to the old SD system. 

  • So what's SD and TZ ignition?  > go to info. side to find out all the salient details.  

  • Gt5A-ES fits more frames with it's 43mm diameter front mount opening can be shimmed down to fit 28mm dia. frame downtubes.   

  • A 7 pcs front mount 1mm tk. Shim package is included.

  • 43mm dia. Front mount has M8 studs.   Spacing is 60mm center to center which allows big downtube clearance. 

  • Rear mount can fit up to 32mm dia. seat posts.

  • Dual Starting:  Can Pedal start normally or you can use a 20V Cordless 1/2" Drill with OCDT. 

  • ES = Easy Start Cordless Tool starting. OCDT means, "Overrunning Clutch Drive Tool" 

  • OCDT is an extra cost attachment tool we sell that enables handheld electric starting. 

  • Unfortunately, our OCDT's are temporally out of stock until we can get a new shipment out of China.    We should have new stock by September.

  • GOOD NEWS:  We have found that a 1/2" or 3/8" drive Ratcheting Adapter can be used instead of an OCDT, however they just don't last as long.   

  • See Ratcheting Adapter pic herein. 

  • 20V Cordless tool with OCDT spins the engine so fast it starts instantly!  Zip wing ding ding purr! 

  • OCDT works like a starter drive in a car starter.. 


  • This engine can be started with a 20v Cordless tool as well as pedal started the normal way.  

  • No need to have a high cost heavy bullet train engine with 12V battery and a ton of headaches with broken pull ropes and failed 12V cheap Chinese starter motors.   

  • The best OCDT starting method is with a modified 1/2" Cordless 20V Impact Tool with soft start but first you must deactivated the 2 flyweight hammers by removing the 4 bolt head and mig spot welding the 2 fly weights in place thus giving a powerful smooth rotation without any hammer effect.  See pic on "How To Weld".   If an impact driver is used without the hammer deactivated you will end up destroying engine bearings and the OCDT too, doing so is not warranty. 

  • Light weight and quick start is the way to go!  

  • Harbor Freight has lowest price for Cordless 20V 1/2" Drills and Impacts.  Watch for sales adds:

  • Gt5A engine is the most powerful 66cc 47x38 so called 80cc stock bicycle engine on the market.

  • Our dealer, Pedal Choppers, in Ft Myers FL says Gt5A has 20% more power than brand X.   

  • Has Round exhaust port to fit round exhaust pipe for free flow scavenging.

  • New crankcase and new cylinder design for improved power output.

  • With included shims engine fits up to 43mm dia. Bicycle down tubes.   Ideal for Aluminum frames.  A Dual U Bolt front clamp is available at extra cost.  ( Order separately )

  • Consider ordering our HP head that works great with a thin copper gasket which enables higher compression for higher horsepower. 

  • Has hardened 8mm dia. front mounting studs not the smaller 6mm dia. studs found on cheaper brand X engines.

  • This add is for a Long Block Engine only;  Supplied without tank, Carburetor, or Muffler, but we do include a high performance TZ CDI with this engine so you are assured it matches the TZ high performance rotor magnet.

  • Use your existing parts or select new installation parts from our component listings.

  • Complete engine installation kit available under separate listing. 

  • This engine is ideal for worn out engine replacement or for making a custom DIY installation. 

  • You can use SICK BIKE PARTS multi shift kit but engine pedal starting can be laborious and strenuous hence the real value of OCDT electric start. 

  • Of course the Bicycle, and Cordless Tools shown in pictures are not included with this long block engine. 

  •   If you are installing this engine on a bike with a downtube smaller than 43mm dia. you will need to use 1mm thick half moon shims to reduce the mount opening to fit your downtube.   ( As of Nov. 15 2020 a 7 pc Shim kit is included. )  

  • Please know that starting on Sept 1st 2021 we will no longer ship to Canada due to our Canadian SkyHawk Dealer in Beamsville Ontario getting fresh inventory arriving there by Sept 1st.  SkyHawk engines going to Canada will not be OCDT compatible.