Ok,
Thank you all for your fast help.
beta boy: You are right. I found the same warning on my TTS Bottle.
First I am going to correct my mixing ratio to 50:1 while i'm using Castrol TTS.
Gaff:
Later i will change to some Shell full synthetic oil which will work with 80:1.
The next trial dealer in my area is about 200 km away from me, an the montesa is a very rare bike in austria. The fork stanchions have a strange color -they really look black on the picture, but sometimes they look yellow? (or kind of Titan-color) no choke :-)
Martin Belair:
That's right, it's a PHBH 26cs. So the jetting seems to be nearly allright? I will try the bigger Jets from 125 - 128.
I am using unleaded fuel.
michael