ducatipaso.org

Hello frinds,
I'm trying to assamble a 5,5 wheel into my 750Sport. I will use a 170 tyre.
Now I have the problem the sprocket is as much as more close to the swing arm like the original sprocket (16" wheel).
What can I do to get the exactly "chainline" back? Do I need a special sprocket for the engine side?

Thomas

Hi Thomas,

here is a short report about the conversion.
http://www.ducati-club-cavallo.de/technik/750s.htm

Perhaps helpful for you

ved

Use the sprocket carrier from the 4.5" wheel.
Both sprocket carriers start from the same casting, but the one for the 4.5" rim gets machined down more on the sprocket face, putting the chainline more inboard. If you have the two in your hand, you can see the difference. Chain runs close to the rear tire, but that's OK. Even light rubbing is acceptable (keeps your chain clean)
The 4.5" wheel was commonly on 5 speed engines, and the 5.5" wheels were on the 6 speed engines. The countershaft sprocket on the 6 speed sits a bit more outboard than the 5 speed. Hence the different sprocket carriers.
Usually cheap on e-bay, and often with a sprocket attached, and the spacers included.

Sorry, I don't know the part numbers.

Just a word of caution. Do you know about the odd wheel spacers on those wheel sets? The last one on the sprocket side mounts what appears to be backward. The big flat side touches the swing arm, and the cone side goes to the wheel to touch off on the ID of the bearing on the sprocket carrier. Lots of people get this wrong and ruin the swing arm and rear wheel bearings.

Cheers,

Hello ducinthebay,
thank you very much for your replay!
I have both sprocket carriers so I can try it yet. But is it nessesary also to use an other engine side sproket to fix the distance or can I forget the distance? I Think it is a difference of approx. 8mm between org. and 4,5" sprocket carrier.

Cheers
Thomas

Hi Thomas , this is a pic of my 906 paso sprocket and as you can see it is offset . When changing my 906 to 17 wheels ( I have both a 4.5" and 5.5" wheels but only the 5.5" sprocket carrier ) I found that with the 5.5" wheel and carrier correctly centered ( had to move the whole assy over 4mm to the left .....took 4mm off the inside of the left excenter ) by simply fitting the front sprocket on the other way everything lined up spot on , no tire rubbing and good clearance for the chain / frame . Maybe a 906 sprocket could solve the problem ?

Certainly check the chainline when you do this modification. A bad alignment will destroy a chain quickly, often with bad results.

- Center the wheel by measuring from the axle to the pivot pin on both sides to make sure the wheel is square, and aligned in the swing arm properly. (there's a tool for that if you want) http://www.rhinomoto.com/tools.html
- Use a laser with magnet base attached to your rear sprocket to align to the front sprocket. (you can buy such a thing on line exactly for this purpose). http://toolmonger.com/2006/12/19/reader ... profi-cat/

I have used both of these on my last build and they work great.

Make adjustments of parts from there. There are some dished front C/S sprockets that will put the chain line outside even more. They came on the early 750 Sports before they shifted the motor over in the frame with spacers. Not easy to find, but a few members have some sitting on their shelves.

McTool, your sprocket looks to be put on backwards, but that would certainly get the chain inboard more. Lots of room to machine off material on that side for fine adjustment.

Cheers, Phil

ducinthebay wrote:McTool, your sprocket looks to be put on backwards, but that would certainly get the chain inboard more. Lots of room to machine off material on that side for fine adjustment.

Cheers, Phil

Its the right way round for me with standard (16" ) wheels , I even had to pack the rear sprocket out 1mm to get proper alignment ,which was one of the 1st things I noticed when I bought the bike......both the sprockets were wearing on one side more than the other ....front on the outside and rear on the inside .... nothing major but easily put right and anyhow I was itchin' to have fiddle with something.... shee-it!, did I ever get the right bike for that ! there aint nothin' that has not been fiddled with