VHM

De Vlonder 208
5427 DH Boekel
The Netherlands

Tel. +31(0) 492 32 45 95

info@vhm.nl

Piston height of VHM
Piston height

Manual piston height measurement

This manual discribes how to measure the piston height for using the VHM cylinder heads and inserts on your motorcycle.

Before using the piston height measuring tool, you must adjust the measurement tool to "0" and it has to be done before every measurement.

(On the left picture you can see the piston height measuring tool, on the right you have a view of setting the dial indicator to "0")

Put the top part of the tool on the flat bottom. Fit the dial indicator in the top part and adjust the zero level to 5mm, by moving the dial indicator in the upper part. Then tighten the screw carefully. Check if the big pointer is pointing to "0", if not, turn the outer ring of the dial indicator to adjust to "0".

During the measuring, be sure that the piston is at Top Dead Center (TDC).

  • When the top of the piston is above the cylinder deck, this is called a positive (+) piston height.
    (left picture)
  • When the top of the piston is below the cylinder deck, this is called a negative (-) piston height.
    (right picture)

In the situation when the top of the piston is above the cylinder deck.

  • The little pointer has turned 7mm.
  • The big pointer turns clockwise and stops in TDC at + 0,16mm.
  • This means that the piston has travelled 7 + 0,16 = 7,16mm. Because you've adjusted the zero level at 5mm, the piston height is 7,16 - 5 = 2,16mm.
  • The top of the piston is 2,16mm above the cylinder deck.

In the situation when the top of the piston is below the cylinder deck at TDC.

  • The big pointer turns clockwise and stops in TDC at 0,32mm.
  • The little pointer has only turned 4mm.
  • This means that the piston has travelled 4 + 0,32 = 4,32mm. Because you've adjusted the zero level at 5mm, the piston height is 4,32 - 5 = -0,68mm.
  • The top of the piston is 0,68mm under the cylinder deck.

ATTENTION: Do NOT make the mistake to think that the piston height is -0,32mm!



Click here for the Pricelist download page.
VHM logo
VHM

De Vlonder 208
5427 DH Boekel
The Netherlands
CC (KvK): 16076527
Tel. +31(0) 492 32 45 95
Fax +31(0) 492 32 20 84
info@vhm.nl
www.vhm.nl