Dimensions rotating valve Kreidler 5V and 6V

Special Parts Foekema-Kreidler 50cc-Racing
Latest update Januari 21, 2004
Cranckshaft changes
The cranckshaft has to be changed as you see in figure 1.
The dimensions are in mm for 5 and 6-speed the same:
A= 19,6 (from bearing point)
B= 17
C= 27
D= 17
E= 14
F= log 2 mm dept about 6 mm
G= O-ring 12,5x1,75 (to close air)

Figure 1

6-edge dimensions
The 6 edge can be 22 and 24 mm, 22mm if a central balance piece is used and 24mm if only the hard disc metal is used.
We prefer the 24mm method, without central balance.
The dimension of figure 2 are:
A= 22 or 24
B= 17
C= 14
D= 10
E= 11
F= 2 (6-speed)
G= 6 (2+6 for 5-speed)

Figuur 2

6-edge dimensions of position on the cranckshaft
The dimensions from figure 3 are:

A=11,6 B=10 C=11 D=21 E=17 F= 22,5

A=17,6 B=10 C=11 D=21 E=17 F= 22,5
(everything 6 mm to the left)

Figure 3

Disc valve
The disc material has to be springsteel material. The thickness can be from 0,3 till 0,7 normaly is used 0,4 or 0,5 mm After sawing the rough form and making a 6-edge log of exactly 22 or 24 mm, you have to make the outside in an exactly circle. You may do it by handwork, but the last little piece is better to do it on the bench lathe. The timing of the valve can be different but in most cases an opening of about 200 degrees is the best, but this will be a subject in "Tuning"
The dimensions from figure 4 are:
A= 106
B= 22/24 (in the picture B= 22)
C= 24

Figure 4

Inside part of disc valve home
The dimensions of the inner half of the diskhome in figure 4a and 4b are:
A= 10
B= 6
C= 123
D= 107
E= 28
F= 2 (little flat side)

Figure 5a
Figure 5b

Disc valve Homecover
The dimensions of the outside dischome cover in figure 6:
A= 5,5-6
B= 9,5
C= 106,9
D= 28
E= 25 (seal 17*25*4)
f= 17,6
G= 29 (temp.piece bench lath)
H= 6,1 (6m bolts)
I= 24-28 (carburater)
J= 1,5-2,0 (only 6-speed)
K= 4 (seal)
L= 4 (6 edge room)
M= 2

Figure 6
Home outside cover

Discvalve room
The extra room (tolerance) of the discvalve has to be as narrow as possible. So it may be between 0,3mm to 0,5mm. In our engines we mostly used 0,4mm, it is safety and works well.

Prepairing for rotating valve
There will be soon a new page for molding the aluminium and flatphrasing the cranckscase after the molding peace has been fixed. In the mean time look for the molding picture.

Ask me is something is not clear enough.

Molding aluminium
If the English version is not ready, you will be connected to the Dutch version
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