Introducing you to Roy Don Butler who owns and operates Don's Speed Shop dba: Pedals to Power in Chickasha OK. Don is a full time engine builder that takes our Gt5A-ES engine to the next plateau of performance.
Here's what he does.
Disassembles stock SkyHawk engine and drills more holes in the crank fly wheels to match the counterbalance weight of the piston, pin and connecting rod.
Removes the stock SkyHawk cylinder and piston.
Installs the Taiwan manufactured Falcon Nikasil plated 911 Cylinder & special made windowed Piston assembly.
The 911 cylinder and piston changes the stroke to 40mm with the addition of a 2mm bottom spacer thus making a 69cc engine displacement.
The different piston wrist pin location allows for the 3cc change in engine cc displacement changing from 66cc to 69cc.
Removes the Stock SkyHawk Clutch shaft spring and installs a 3 spring heavy duty clutch plate which prevents a slipping clutch due to higher achieved horsepower.
Installs a Dio Reed Valve assembly for piston port induction.
Installs a high quality 21mm dia. slide valve carburetor which is much bigger than the 14.95 dia. slide valve found with stock China doll engines.
Installs a high compression CNC head with copper gasket.
Bench runs a live test with a dedicated carb to confirm all is copasetic.
The engine is shipped with a untuned CARB DUE TO NOT BEING ABLE TO SHIP A CARB THAT HAS HAD GAS IN IT.
Don includes an assortment of jets so the end user can tune as required for the conditions in their locality.
This engine is not a fuel saving get around town on a dime engine. It's made to turn enthusiasm into fear!
Don says 60mph has been documented with this engine properly tuned with expansion chamber exhaust and ran with the right ratio rear sprocket on flat land when ridden by a trained Chimpanzee. Just kidding about the unknown rider!
The SkyHawk cordless drill start OCDT feature is appreciated when starting this hopped up engine.
When you order this engine we have it dropped shipped direct from Don's shop to you.
We provide you with the contact email and phone # so you can deal direct with Don on any issues of importance.