Details
https://www.greenlandmx.co.uk/en/vhm-12%C2%BA-piston-ktm-sx-65-09-24-husqvarna-tc-65-17-24-gas-gas-mc-65-21-24/APKT06521722-P.htmlVHM 12º Piston
This 12º VHM piston is specially developed for a maximum performance gain.
- It must be used in combination with a VHM 12º insert and head.
- 100% CNC machined from high quality material and has a non-circular profile, stand for high performance, longevity and keeping high performance during it's lifetime.
- Use in combination with VHM insert AE32167-059 and VHM head AA33112.
*This piston needs a clearance of minimum 0.04mm and maximum 0.05mm! ALWAYS CHECK CYLINDER BORE, some new 65SX engines have bore Ø45.03 and thus need piston Ø44.99. Must be used in combination with a VHM 12° insert and head.*
VHM 12º Kolben
Dieser 12º VHM Kolben ist speziell für die maximale Leistungssteigerung entwickelt.
Brand | VHM |
Modality | Cross/Enduro |
Primary material | Aluminium |
HOW TO MEASSURE ANY DIRT BIKE´S PISTONS
The pistons of any internal combustion engine, two or four-stroke, are conical and oval, to control its expansion in its operation. To get to know your maximum measurement you have to measure at 10-12 mm. of the skirt, in the opposite part to the bolt.
When we see a mark on the head of the piston, for example, 80 mm. or we have a cylinder of 80 mm. this measure is corresponds to the cylinder, when meassuing the piston we will see that actually measurement is 79.95 mm., the tolerance between piston and cylinder would be 5 cents (0.05 mm.).
In the aluminum cylinders with hard chrome interior treatment, already in disuse, or NIKASIL the measure of 80 mm. It is usually fixed to 80 mm.
The pistons work with tolerances between 4 to 6 hundredths (0.04-0.06) for two-stroke engines and 3 to 4 hundredths for four-stroke engines (0.03-0.04). To fix a deformed cylinder, the interior of the cylinder shall be polished first and the measurement is adjusted with pistons that are over-measured for this purpose, marked with letters A-B-C-D (selection); the lowest measure being A, increasing 1 hundredth per letter; that is, selection B 0.01 mm. greater than A, C 0.02 mm. greater than A, etc.
EXAMPLES
New Cylinder Ø 80.00 mm. mounts a piston of Ø 79,97 A Factory Tolerance 0.03 mm.
Polished Cylinder Ø 80,01 mm. mounts a piston Ø 79,98 B Factory Tolerance 0,03 mm.
Polished Cylinder Ø 80,02 mm. mounts a piston Ø 79,99 C Factory Tolerance 0,03 mm.
Polished Cylinder Ø 80,03 mm. mounts a piston Ø 80,00 D Factory Tolerance 0,03 mm.
The important thing is to maintain the tolerance, which the manufacturer recommends, between cylinder and piston.