Dear G., dear all
Thanks for the fast reply.
Indeed this seems to be a bit confusing:
• My swiss 906 had orginally a 15 / 34 combination (no typo) and some other modifications to reduce power – but there is nobody around here who is still using these reducation measurers. The current combination on my bike is 14 / 40 together with my last set of Michelins.
• I checked different sources and got different informations:
• My owner’s manuel (written in german) says 15 / 40, swiss model 15 /34.
• The same holds true for my repair manuel (written in 4 different languanges).
• The chain kits for the 906 I could find in the internet / on ebay had the 15 / 40 combination (very seldom a 15 / 38).
• The first tests of the bike like in motorrad 3/1989 and PS 10/1989 write 15 / 38 (the tests are availiable here on the ducatipaso.org). I do not think these are typos because the gear/speed diagramms are right for the Paso 906 with 15 / 38 (I did some calculations with geradata).
• The english owner’s manuel indeed says 15 / 41. Somebody here on the forum said that firt 906 had 15 / 38, later models 15 / 40.
In any case, why is this important? I am currently switching to the Avon combination that just got an approvable from Ducati Germany. It is a ZR-rated matching pair and it seems to be not a perfect but a quite good way for the transformation. In order to be close to a 15 / 40 combinations with the original Michelins, I bought the tires (they are already on the bike) and a longer chain with 14 / 40 and gave it to the garage where the swap is done. I talked to the mechanic and he told be there is a problem (I was wrong with saying the chain hits the swingarm). It seems to me that the problem has already been discussed in the forum by pasoist:
• I installed a 150/80 rear tire on my 750. Only modifications I had to do were a longer chain (108 links instead of 106) in order to get the tire rear enough. (Otherwise the tire does not have enough room to rotate.). And a larger rear sprocket (40 teeth instead of 38), in order to get the chain tight enough (with the 38 tooth sprocket there´s not enough adjustment range to tighten the chain). Pretty simple anyways, didn´t have to do any irreversible changes to the bike.
viewtopic.php?f=1&t=4284&p=33638&hilit=150+%2F+80+38+sprocket#p33638 Hence I ordered a 15 front sprocket and will get that on Tuesday. Hopefully that will do it: Disadvantage: The gear transmission ratio is quite long, but I do not know how to change it.
I try to get a Z41 (also checked your suggestions G.), but I could not get one.
Whenever everything is done I will show some pictures and tell the forum my first driving experience with the new combination.
By the way: I checked different threads here in the forum but there is still no clear answer how much the difference (cleareance) between swingarm (front) and tire should be. I think radial tires should not extend to much via centrifugal force, but for instance 5 mm semms not to be a lot if you go for a 150 km/h or more. Any suggestions here?
Thank you and have nice weekend, Hardo
