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piston orientation
piston orientation
On to the cylinder of my 61 R27. So, I'm trying to figure out which way to put the piston onto the rod. While I can see 'Vor' stamped on the top of the Nural piston there is no arrow or anything to say which way is Vor. So, anyone know if, with the piston in my hand and 'Vor' is right side up should the arrow be pointed to the right or left. I am also assuming "Vor' means 'to the front'.
Thanks.
61 R27 and boy do I need parts-- got any?
Oh no, wifes coming home- get the engine out of the oven!
"Are those bearings in the freezer?!" she calmly inquired
- schrader7032
- Posts: 9056
- Joined: Fri Oct 27, 2006 3:00 am
- Location: San Antonio, TX
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Vorn means "front". My R25/2
My R69S pistons had no markings of any kind...not even a Vorn. Turns out the piston has no offset so it didn't make any difference. I installed the piston so that the markings were readable.
My guess is that if you can read the letters Vor(n), the arrow should be pointing to the right.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- Bruce Frey
- Posts: 536
- Joined: Fri Oct 27, 2006 3:00 am
If it says "vorn," there is
IIRC (BIG IF, please check with Vech), the small side faces the direction of rotation. i.e., if you are facing the rear and the crank rotates in a clockwise direction, the small side would be on the left of a vertical cylinder.
Bruce
I have looked long and hard
Any help?
- Attachments
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- vorn.jpg (434.03 KiB) Viewed 2812 times
61 R27 and boy do I need parts-- got any?
Oh no, wifes coming home- get the engine out of the oven!
"Are those bearings in the freezer?!" she calmly inquired
R27 piston stuff cont. . . .
more reading for you and your piston
http://www.beemergarage.com/documents/203.pdf
http://www.beemergarage.com/documents/220.pdf
http://www.beemergarage.com/documents/231.pdf
http://www.beemergarage.com/documents/230.pdf
Thanks--I'll add them to my
Now, can I send my questions for my E-Class also??????
61 R27 and boy do I need parts-- got any?
Oh no, wifes coming home- get the engine out of the oven!
"Are those bearings in the freezer?!" she calmly inquired
- schrader7032
- Posts: 9056
- Joined: Fri Oct 27, 2006 3:00 am
- Location: San Antonio, TX
- Has thanked: 3 times
- Been thanked: 36 times
I asked the German
"the offset is to the right side if you sit on the bike. You can measure it using a caliper - ca. 1,5 mm from the middle."
I take that to mean that the wrist pin will be shifted 1,5 mm from the middle of the piston to the right as you sit on the bike.
Another possibility...are there pockets in the piston dome for valves? If so, wouldn't one pocket be larger than the other to accept the larger intake valve?
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
There are indeed pockets and
Any opinions on that possible arrow in the photo?
61 R27 and boy do I need parts-- got any?
Oh no, wifes coming home- get the engine out of the oven!
"Are those bearings in the freezer?!" she calmly inquired
- schrader7032
- Posts: 9056
- Joined: Fri Oct 27, 2006 3:00 am
- Location: San Antonio, TX
- Has thanked: 3 times
- Been thanked: 36 times
Arrow?
It's possibly an arrow! I really can't hazard a guess as to exactly which way it's pointing.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
R26 / 27 piston
mark "vorn" is ahead (to the front) .
The arrow points into the driving direction.
I suggest you continue to clean the piston top
to reveal any remnents of a arrow".
Does the "vorn" mark favor one side of the piston top
to another ?
also- to press the wrist pin back into the piston,
heat the piston up to 176 ...210*F