SkyHawk Bicycle Engine Kit

( Spooky Tooth Cycles )

Price: $149.00

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150 miles per gallon

Speeds of 19 to 45mph depending on gear ratio

Regularly $250 Limited Time Offer

48cc GT2B, 55cc GT3, 60cc GT33, 66c GT5

Skyhawk bicycle engine

Among midframe mounted bike motors, there is no comparison for the quality of the SkyHawk bicycle engine. The difference is night and day. Such a bold engine deserves a bold statement, and Spooky Tooth stands behind it with the following:

Innovation and Implementation of New Technologies. Spooky Tooth Cycles and Grubee Inc. are constantly searching out ways to constantly make SkyHawk Bicycle Engine line even better. Whether it means the application of RTV sealant to engine seals or the procurement of long life gasoline resistant gaskets, we are always making upgrades to the SkyHawk Engine Kit as new technologies become available.
3 Month Limited Warranty. This SkyHawk Bicycle Engine Kit is covered by a limited liability warranty. Spooky Tooth Cycles warranties that your SkyHawk Bicycle Engine will be free from defects in material and workmanship for 90 days from the date of purchase and that the remaining balance of the Kit Parts are to be free from defects in material and workmanship for 30 days from the date of purchase.
Toll-Free Customer Service and Technical Support Hotline. Should any problems arise, allow our experts to troubleshoot for you. Our technical expertise is unrivaled. We are the best and one of the oldest in the business and can usually walk every customer through the right diagnoses and repair of their motorized bicycle.

The SkyHawk GT5 is the culmination of years of work, research and pressure from every side to create a superior bicycle engine. It looks like a standard 80cc engine on the outside, but the advantages will be increasingly noticeable after extensive riding. The SkyHawk GT5 is a more expensive engine to produce, however, the seasoned motorized bicycle owner knows that quality components pay for themselves many times over. We will guarantee that your engine will be free from defects for 3 months, and that your kit parts will be trouble free for 30 days. If any questions arise, call our toll free line. We are loyal to our customers. At any time during installation or while riding in the future, we can help you troubleshoot over the phone or you can browse our extensive installation manuals online.

How do you compare one bicycle engine to another? Some would say, "This is the best!", but how would you back it up or how would you know?

What does is take for an engine to work? Air, fuel, compression, and spark. If all of these are present, you can have an engine that you will be extremely happy with for years because of its great successes in what you are using it for. But, let's say that one or more of those elements are missing. Maybe you're not getting a spark, there are carburetor issues, or perhaps an air leak occurs because of a bad case casting. These are relatively common problems that, unfortunately, our bicycle engine industry has had to suffer through because of a lack of concern from manufacturers.

Bicycle motors can be long lasting wonderful engines when proper care is given. The process begins with a high standard of quality control with direct factory oversight from Don Grube himself, it continues with an education on installation and maintenance procedures given to the owner, and is followed up with a proper 3 month warranty and plenty of technical support via our toll free hotline.

Newly Designed 66cc Carburetor

For this line of bicycle engine, the NT factory produces a carburetor designed solely for the 66cc SkyHawk engine. This newly revised carburetor incorporates a larger barrel slide throttle body for increased performance and a secondary shut-off valve on the carb itself to avoid accidental overflows. This new carburetor has the air intake & discharge hole diameters 3mm larger on both sides of brass slide. The main jet is slightly larger for improved performance, there is a better screw connection at the gas inlet tube, and the new fuel shut off valve remedies the older problem of leaking carburetors. Up until now, all NT carburetors were solely designed for 48cc engines.

carb testing
Carburetor testing at the NT factory

To meet the strict 2008 US EPA/CARB importation restrictions, all SkyHawk motors are now equipped with a catalytic converter exhaust muffler which incorporates a Palladium Cartridge filter imported from Germany. Although the standard bicycle engine has rarely emitted a visible exhaust with synthetic oil, it is a beautiful thing to see the new Palladium Cartridge filter exhaust completely capture excess atmospheric pollutants.

Final inspection by Don Grube

All SkyHawk Engine Kits include the following:

SkyHawk bicycle engine w/ 3 month warranty
2.5 liter black powder coated gas tank w/ internal chrome plating
44T 9-hole drive sprocket & mounting hardware
Palladium cartridge filter catalytic converter exhaust muffler (EPA approved)
Sealed cartridge bearing chain tensioner (higher life vs. old plastic roller)
410 Drive Chain
Throttle assembly w/ right and left ergonomically shaped grips
Throttle cable pre-installed
Brass fuel valve (vs. cast aluminum valve)
Oversized carburetor w/ fuel shutoff (GT5 only) and chrome air cleaner housing
Factory tested CDI (capacitive discharge ignition)
Push button clutch lever (for easy pedal clutch lock-out)
Inline adjustable clutch cable w/ heat shield springs
Instruction sheets in clear English

Tool Kit & Extras

Other additions only found in the SkyHawk engine line include the following extra items in a Tool Kit for your convenience:

1-Gear puller tool kit - to adjust or overhaul internal engine components
1-Spark plug wrench
1-Extra spark plug
1-Extra head gasket (metal)
2-Extra exhaust gaskets - newly improved with integrated steel liner
1-Extra carburetor idle screw
1-Extra spark plug boot
1-Front motor mount adapter plate for down tubes greater than 1-1/2"
1-Extra rear mount block and 2 long bolts to allow for higher chainring clearance
2-Extra steel motor mount clamps

2.5L Gas tanks plated inside to help prevent rust versus the 2L unplated tank supplied by others.

Carburetor and throttle cable factory pre-assembled for easy installation.

Aside from a cleaner exhaust, another requirement placed on the SkyHawk factory for importation rights is the disclosure of accurate engine size to the consumer. While we have chosen to use the long standing factory branding of the "80cc" name, the true displacement of the GT5 bicycle engine is actually 66cc. The debate has been open for a long time in our motorized bicycle community as to what the correct engine size is and we hope to provide the answer. The volume of a cylinder is calculated by using the formula Volume = Pi x Radius squared x Stroke (multiply 3.142 x radius of bore squared x stroke length divided by 1000). In the East, the displacement of an engine includes the area of the cylinder head's combustion chamber as well as the volume of the cylinder. In the US however, the volume of the cylinder is only considered when identifying engine displacement. With a 47mm bore X 38mm stroke this equals a displacement of 66cc, The SkyHawk GT5 is one of the largest bicycle engines on the market and is the same as the so called 80cc.

Engine Identification

SkyHawk quality is unmatched and Spooky Tooth Cycles is proud to offer GT2B 48cc Round Head & GT5 66cc bicycle engines. "There is no such thing as perfection in China, but the GT5 is light years beyond the competition."