Free printable · Identify your machine
GY6 engine identification chart and worksheet
The measurements and observations that tell you which engine you have when the label is gone — recorded in the order a parts supplier will ask for them.
Layout preview of page one. The PDF itself is typeset text, not an image.
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3 pages. No account, no sign-up, no newsletter. Print it, copy it, hand it to somebody else.
Version v1.0 · September 2026. Opens in your browser's PDF viewer, where you can print directly.
The problem it solves
“It’s a GY6” is where most people stop, and it is not enough to order a part. The family covers several displacements, two crankcase lengths, air and liquid cooling, and a decade of component changes. What actually determines whether a part fits is a handful of measurements — and almost nobody writes them down before they start shopping.
Who it is for
- Owners of an engine with no readable label, sold to them as “a GY6”
- Anyone who has already ordered one wrong part and does not want to order a second
- People rebuilding an engine out of the frame with no machine to reference
What is on it
- A printed millimetre scale to check your printer has not scaled the sheet
- Case type, cooling, and mounting observations with what each one changes
- The measurements that separate one engine from another, with where to measure from
- A tracing area for the CVT cover bolt pattern
- Space for the markings actually cast into your cases
How to use it
- 01Check the calibration bar first with a steel rule. If 100mm is not 100mm, reprint at actual size.
- 02Work with the machine cold and on the stand.
- 03Record what you measure, not what you expect. The value of this sheet is that it is about your engine and not a generic one.
Use it with the registry
Other sheets you may want
- What scooter do I actually have?A one-sheet record of every number that identifies your machine — badge, VIN, engine number, engine family and factory. Fill it in once, photograph it, and never hunt for it again.
- GY6 belt size chart and measuring sheetHow to read the three numbers printed on a scooter drive belt, how to measure a belt that has no readable markings left, and a record sheet for the one you have.
- Mystery part measurement sheetYou are holding a part. Nobody knows what it is called. This sheet records everything a supplier needs in order to find it for you.
Free to print, copy, and share — including in forums, clubs and workshops. If you find a mistake on one of these sheets, tell us and it gets corrected. Every sheet carries a version so you can tell which one you have. All printables.