Professional Two-Stroke Engine Rebuilding
Ken OConnor Racing provides professional two-stroke engine rebuilding and machine work for motorcycle and ATV riders who expect precision, reliability, and attention to detail. Whether your engine needs a top-end rebuild, cylinder machining, crankshaft service, or a complete engine rebuild, every job begins with a thorough inspection and accurate measurement of critical components.
All engine machining and assembly is performed in-house at our Danielson, Connecticut machine shop, allowing us to control the quality of the work from inspection through final assembly. Engines are built around their intended use—from dependable trail and recreational machines to high-performance and race applications.
Local customers are welcome to bring engines and components directly to our shop, and we accept shipped-in engine work from customers throughout the world
Whether your engine is worn, damaged, or being prepared for a performance build, let us help you achieve your goals. We will assess the parts and recommend the work the engine actually needs. Contact us about your two-stroke rebuild or call (860) 230-5003.
Kawasaki H2
Complete Two-Stroke Engine Rebuilds
A complete rebuild can involve much more than replacing a piston. Depending on the engine’s condition, the job may include crankshaft rebuilding, cylinder repair, bearings and seals, crankcase work, cylinder head machining, and final assembly. We inspect the engine and discuss the parts and machining required before setting the scope of the build.
Our motorcycle and ATV engine assembly service covers cleaning and preparation, checking critical clearances, fitting components, assembling the crankcases and top end, and leak-down testing of applicable two-stroke builds. We build for reliable trail use, restoration, and performance applications, with the parts and machining selected for the particular engine.
Top-End Rebuilds
If the crankshaft and lower end are sound, a top-end rebuild may be the appropriate repair. We inspect the piston, rings, cylinder, head, gasket surfaces, and related components, then determine whether the bore needs machining or the cylinder needs another repair. See our cylinder boring and honing service for cast-iron bores and our cylinder plating service for plated cylinders.
Bottom-End and Crankcase Rebuilds
When the lower end needs attention, we can inspect the crankshaft, bearings, seals, cases, and transmission components as the job requires. Our crankshaft rebuilding service includes connecting rod replacement and crankshaft truing. We can also discuss damaged cases, bearing installation, and other needed repairs after inspection.
Two-Stroke Machine Shop Services
Having the machining and engine assembly coordinated through one shop helps keep the build focused on the complete engine combination. Available services include:
- Crankshaft rebuilding and truing: connecting rod replacement, assembly, measurement, and truing for many single- and twin-cylinder applications.
- Cylinder boring and honing: measuring and machining cast-iron bores to suit the piston, with attention to the finish and two-stroke port edges.
- Cylinder plating and repair: options for worn or damaged plated cylinders, evaluated according to the cylinder’s condition.
- Cylinder sleeving: replacement sleeves for suitable cylinders, followed by the machining needed for proper fit and finish.
- Two-stroke cylinder head machining: combustion chamber and squish work matched to the piston, fuel, and intended use.
- Two-stroke porting: port work planned around trail riding, aggressive performance, or racing goals.
- Flywheel lightening: an available option for compatible performance builds.
- Complete engine assembly: careful installation and checking of the finished engine components.
Not every engine needs every service. We can handle an individual component or coordinate the machining and assembly for a complete build.
Built for Your Motorcycle or ATV
We work on two-stroke motorcycle and ATV engines from a range of manufacturers, including Yamaha, Honda, Kawasaki, Suzuki, Maico, Gas Gas, Husqvarna, TM, and KTM applications. Contact us with your make, model, year, displacement, current modifications, and intended use and we can confirm the work available for your particular engine.
How to Start an Engine Rebuild
- Tell us about the engine. Contact Ken OConnor Racing with the model, symptoms, any previous work, and whether you want a stock rebuild or a performance build.
- Confirm the job before sending parts. We can discuss the likely scope, what to send, and which decisions depend on inspection.
- Ship or bring in the engine or components. Follow our shipping instructions and include the required identification and job information. Drain all fluids before shipping a complete engine.
- Inspection, machining, and assembly. We evaluate the parts, confirm needed repairs, complete the agreed work, and check the finished build.
Pricing depends on the engine, its condition, the parts required, and the work selected. See our general service pricing for published starting points, then contact us for your specific job. Return shipping is additional.
Why Riders Choose Ken OConnor Racing
Ken OConnor Racing has been serving motorcycle and ATV riders since 1983. We are an engine machine shop as well as engine builders: cylinder work, crankshaft work, head machining, and engine assembly are part of our day-to-day business. You can see more of the shop and our approach on the About Us page and read customer testimonials.
Ready to discuss a two-stroke engine rebuild? Send us your engine details or call (860) 230-5003.
Frequently Asked Questions
Nationwide two stroke mail in engine rebuilding service
Ken OConnor Racing provides professional two stroke engine rebuilding and machine services for customers throughout the United States. Customers do not need to be located near our Connecticut machine shop. Complete two stroke engines, cylinders, crankshafts and other engine components can be shipped directly to Ken OConnor Racing for inspection, machining and rebuilding. All machining and engine assembly is performed in-house at our Danielson, Connecticut facility.
Do I need a top-end rebuild or a complete engine rebuild?
That depends on the condition of the cylinder, crankshaft, bearings, seals, and other components. Describe the problem when you contact us; inspection and measurement determine the recommended repair.
Can I ship my two-stroke engine to your shop?
Yes. Contact us before shipping, then use our shipping instructions to pack and identify the job. Drain all fluids from a complete engine before shipment.
Can you rebuild my crankshaft or machine my cylinder without assembling the whole engine?
Yes. We offer individual services, including crankshaft rebuilding, cylinder boring, and cylinder head machining.
How much does a two-stroke engine rebuild cost?
Cost depends on the model, damage, parts, and machine work. Review our service pricing and contact us with your engine details.