VHM KTM SX 250 06-24 HVA TC 250 14-24 Gas Gas MC 250 22-24 12º Piston (Coated)
Details
https://www.greenlandmx.com/int/en/vhm_ktm_sx_250_06-24_hva_tc_250_14-24_gas_gas_mc_250_22-24_12%C2%BA_piston_%28coated%29/APKT25021754-P.html
VHM KTM SX 250 06-24 HVA TC 250 14-24 Gas Gas MC 250 22-24 12º Piston (Coated)
VHM 12º Piston (Coated).
This 12° VHM piston is specially developed for a maximum performance gain.
- It must be used in combination with a VHM 12° insert and head.
- This piston is 100% CNC machined from high quality material and has a non-circular profile.
- They stand for high performance, longevity and keeping high performance during it's lifetime.
- The pistons has a black coloured coating on the piston skirt to reduce friction and wear.
- Use in combination with:
-
- VHM insert AE32337-024 and head AA33209 (for KTM SX 250 23-24/ HVA TC 250 23-24/ Gas Gas MC 250 2024)
- VHM insert AE32272-024 and head AA33166 (for KTM SX 250 17-22/ HVA TC 250 17-22)
- VHM insert AE32129-068 and head AA33098 (for KTM SX 250 07-16/ HVA TC 250 14-16)
This piston needs a clearance of 0.07 mm, VHM standard size is Ø66.33. Must be used in combination with a VHM 12° insert and head.
| Brand | VHM |
| Modality | Cross/Enduro |
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.
