01
Bore alignment drifts after heat
A crankcase half machined in two setups can shift the main bearing bore by 0.02 mm or more. The crank then drags, the bearing runs hot, and the whole bottom end comes back apart.
Motorcycle Engine Parts
Custom CNC e2 80 Machined Motorcycle Engine Parts
Engine cases, covers, rocker arms and flexible drive shafts machined to ±0.005 mm. We quote in 12 hours, start production in 24, and ship from one prototype to 10,000+ parts.
±0.005 mm tolerance16 five-axis centersISO 9001:2015No MOQ
±0.005 mmAchievable tolerance on critical fits
16Simultaneous 5-axis machining centers
3–5 daysTypical shipping window after machining
100%Inspection before shipment
Common Failures
Where engine parts go wrong
Four problems we see on almost every incoming drawing.
02
Cover sealing faces leak
A cover face that is not flat within 0.01 mm will not hold gasket crush. Oil weeps past the joint at high rpm and the customer blames the gasket, not the machining.
03
Port walls break through
Wall thickness is often left to the casting. Cut 0.5 mm too deep and the port breaks into the water jacket. The head is scrap before it ever runs.
04
Rebuild parts do not fit
A rocker or shaft made from a worn sample instead of a controlled drawing will not repeat. Ten units fit, the eleventh binds, and the batch is suspect.
The Approach
One setup, one fixture, one controlled datum
How we keep engine parts repeating from the first article to the ten-thousandth.
5-Axis Setup
Critical features cut without re-clamping
Crankcase halves, cylinder heads and covers carry bores, faces and bolt patterns that all reference each other. Splitting those features across two or three machines stacks every fixture error on top of the last one. On a simultaneous 5-axis center we reach five sides in one setup. The main bore, the deck face and the cam bore come off the same datum.
That matters most on parts that see heat. A uniform wall and a bore that is true to the deck keep clearances stable as the engine reaches temperature. We fixture off the casting's machined pads, not the raw skin, so the first operation does not chase a rough surface.
- 1Bore-to-deck alignmentHeld within ±0.005 mm on critical fits
- 2Five sides per setupFewer fixtures, less stacked error
- 3Thin-wall controlLight finishing passes limit distortion
Materials
The alloy decides how the part behaves
Engine work is mostly aluminum, and the grade is not interchangeable. 6061-T6 machines cleanly and takes anodizing well, which suits covers, brackets and housings. 7075 gives higher strength for rocker arms and stressed linkages but welds poorly and moves more under heat. 6082 sits between them and is common on European engine platforms.
For wear surfaces we switch to steel or stainless. 4140 and 4340 hold a hardened rocker pad. 17-4PH gives corrosion resistance with strength after aging. Bronze valve guides and beryllium copper contacts machine to tight bores without galling. We check incoming stock before it reaches a spindle.
- 1Aluminum6061-T6, 7075, 6082, ADC12 for covers and cases
- 2Steel and stainless4140, 4340, 17-4PH for wear parts
- 3Bronze and copperC93200-type guides, beryllium copper contacts
Fit the Process to the Feature
Which process for which engine feature
Use this to decide before you send the drawing.
| Feature | Process | Why |
|---|---|---|
| Crankcase half, main bore | Simultaneous 5-axis | Bore and deck in one datum |
| Cylinder head, port work | 5-axis with ball-nose finishing | Controlled wall thickness |
| Flexible drive shaft | Mill-turn, Ø400 mm rotary | Concentric turning and milling |
| Valve guide, bushing | CNC turning | Roundness on a long bore |
| Cover with seal groove | 3-axis + drill/tap | Flat face, simple geometry |
| Rocker arm, hardened pad | 4-axis + heat treat | Repeatable pad location |
What We Machine
Engine part families we run
One shop for the whole bottom and top end.
01
Crankcases and covers
Split cases, clutch covers, stator covers, oil pans. Bores and sealing faces held to ±0.005 mm with flatness controlled across the gasket joint.
02
Cylinder heads and ports
Combustion chambers, valve seats, port walls. 5-axis finishing keeps wall thickness even so the casting does not break through.
03
Flexible drive shafts
Mill-turn work on Ø400 mm rotary tables. Concentric diameters and splines cut in one setup to hold runout.
04
Rocker arms and linkages
4-axis milling of pads, pivot bores and lightening pockets. Steel grades machined before or after heat treat.
05
Fuel and oil system parts
Pump housings, fittings, injector bodies. Stainless and aluminum with sealing faces machined to Ra 0.8–1.6 μm.
06
Prototype and low volume
One-off development parts through to 10,000+ piece runs. No minimum order quantity on any family.
Capability
Machining scope and inspection
Numbers we can commit to.
| Item | Specification |
|---|---|
| Tolerance | ±0.005 mm (±0.0002 in) |
| Fine finish | Ra 0.2–0.8 μm |
| Standard finish | Ra 0.8–1.6 μm |
| As-machined finish | Ra 1.6–3.2 μm |
| Maximum part size | 4,000 mm |
| Rotary table | Ø400 mm |
| Inspection | 100% before shipment, reports on request |
| Qualification rate | 99.99% |
Why GreatLight
What you get on the shop floor
Fifteen years of engine and drivetrain work, three plants, 150 technicians.
15Y
Machining since 2011
Three wholly-owned plants across 7,600 m², running prototype work and production runs on the same floor.
127
High-precision CNC machines
16 simultaneous 5-axis centers, 16 mill-turn centers and 12 four-axis mills cover most engine geometries.
12h
Quote and DFM in 12 hours
Send a STEP file and we return pricing plus a manufacturability review the same working day.
24h
Production starts in 24 hours
Once the drawing and material are locked, the first operation can begin the next day.
<2%
Historical late-delivery rate
When a delay is unavoidable we tell you early by email or WhatsApp instead of at the ship date.
ISO
Four certified systems
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022 govern the process.
7,600 m²Manufacturing space
150Technicians on staff
16Five-axis machining centers
10,000+Parts per run supported
Industry Requirements
What these sectors ask for, and what we deliver
Motorcycle powertrain
Cases and covers must hold bore alignment after thermal cycling.
- ±0.005 mm
- Ra 0.8–1.6 μm
- 100% inspection
Powersports rebuild market
Small batches of rockers and shafts need to repeat without hard tooling.
- No MOQ
- 3–5 day ship
- 24 h start
Automotive and EV driveline
IATF-governed programs need documented inspection at every stage.
- IATF 16949
- In-process checks
- Reports on request
Industrial engine components
Pump and housing parts must seal at pressure with flat faces.
- Flatness control
- Stainless and aluminum
- 99.99% qualification
FAQs
Questions engineers ask before ordering
What file formats do you need for a quote?
A STEP or IGES model plus a 2D drawing that calls out tolerances, datums and surface finishes. If the drawing is incomplete we mark the gaps in the DFM review rather than guess.
Send what you have. A model alone is enough to start the review, and we will ask about the critical fits.
Can you hold ±0.005 mm on a crankcase bore?
Yes, on features we can reach in one setup on a 5-axis center. The bore and its reference face should be machined from the same datum.
If the drawing puts the bore on a different datum than the deck, expect to pay for an extra operation. We flag that in the quote.
Which aluminum should I pick for a cover?
6061-T6 for most covers. It machines well, anodizes evenly and resists stress corrosion.
Choose 7075 only if you need the extra strength and can accept lower weldability. 6082 is a good middle option on European platforms.
Do you machine hardened steel parts?
We machine 4140, 4340 and 17-4PH in the annealed or pre-hardened condition, then you heat treat and we finish the critical fits.
Cutting fully hardened rocker pads is possible but slow. It is usually cheaper to leave grinding stock and finish after treatment.
What is the minimum order quantity?
None. We run from a single prototype to 10,000+ piece production batches.
Prototype pricing is higher per part because of setup. Cost per piece drops once fixtures exist and the process is fixed.
How do you protect my design?
Uploads stay confidential and are handled under access control. We sign an NDA on request before drawings are shared.
Files are not reused for other customers or shown as samples without written permission.
How fast can I get parts?
Quotation and DFM analysis within 12 hours. Production can start within 24 hours of drawing and material sign-off.
Most parts ship in 3–5 days after machining. The historical late-delivery probability is below 2%.
Do you supply inspection reports?
Yes, on request. We record a raw material check, in-process monitoring and a final inspection, and every part is checked before shipment.
First article reports and dimensional layouts are available for production programs.
Send your engine part drawing
Upload a STEP file and get pricing plus a manufacturability review within 12 hours. No minimum order quantity, from one prototype to 10,000+ parts.
12-hour quote100% inspectionNo MOQNDA on request
