KTM 50 Magnet

Note: The KTM magnet keyway is precisely machined. However, the stock keys are made of stamped steel, and the magnet keyways are not tightly machined. Installing the magnet might need some key adjustments.

KTM Magnet – Precision Fit for ChinaGirl Crankshafts

This re-machined KTM magnet is designed with a precision-cut keyway to fit ChinaGirl-style (66/80cc) 2-stroke engine crankshafts. Stock magnets are made from layered stamped steel and often have loose tolerances, causing excessive movement and unreliable ignition timing.

This upgraded magnet provides a tighter, more accurate fit, reducing rotational play and improving engine performance.

Key Features:

• Precision-machined keyway for ChinaGirl crankshafts
• Reduced magnet movement compared to stock (less than 1° vs. 5–6°)
• Improved ignition timing consistency
• Compatible with 66cc / 80cc 2-stroke engines (ChinaGirl style)

Installation Guide:

Step 1: Prep the Crankshaft
Stock crankshafts often have a small burr in the keyway from the machining process.
→ Lightly file the keyway surface until smooth so the magnet can slide on easily.
(Refer to Pictures 1 & 2)

Step 2: Inspect the Stock Key
Most factory keys are stamped steel and not flat.
→ Picture 3 shows a partially filed key that is clearly uneven.
(Refer to Picture 3)

Step 3: File the Key Flat
Hold the key firmly with your thumb and slide it along a flat file.
→ This will even out the surface for a proper fit.
(Refer to Pictures 4 & 5)

Step 4: Test the Fit
Once filed flat, the key should pass smoothly through the magnet keyway with no resistance.
(Refer to Picture 5)

Step 5: Measure Key Height (Refer to Picture 6)
The depth of keyways can vary between crankshafts.
→ Check that the key does not stick too far out. The total height of the crankshaft plus key should be no more than ~9.1mm.
→ If needed, file the top of the key down to achieve the correct height.
In the example shown, the keyway was cut deep, resulting in a total height of 8.96mm, allowing the magnet to slide on cleanly.

End Result:

Stock magnets tend to rock on the shaft by 5–6°, which can cause misfiring or timing issues.
This upgraded magnet setup offers a tight, secure fit with significantly less movement, providing better ignition performance and long-term reliability.

• Listing includes KTM Magnet