I want a 748 engine in the S2R, now that would be sweet.
But I guess it couldn't really be called the S2R then since it would be a desmoquatro.
Dry clutch conversion really isn't that bad. You'll need the following items from a dry bike:
clutch side engine cover
clutch driven gear
Clutch assembly *see below
some kind of rubber bushing to shim in between the pushrod and pressure plate
IIRC thats it.
You may not need to swap out the primary gear if you get a clutch driven gear from a 900 SS. The gears I got were from a 748 so the clutch driven gear did not quite mesh with the 620 SS primary by a 1mm or 2. But you'll have to check that out yourself.
The trick is that the 5 speed wet clutch setup has a shorter input shaft(I guess thats what I'll call it...where the clutch mounts) than the 6 speed dry clutch setup. So when you throw the basket and hub on the input shaft there are only one or two threads showing up at the end of the input shaft.
The solution is to machine down the hub by around 10mm. Then you are able to mount the hub and torque the hub nut down. The problem with this solution is that the stock dry clutch hub really doesn't lend itself to being machined down(its a solid, thick unit). So I went with the yoyodyne lightweight setup which was really easy to machine down to the desired amount.
Another route you can take is to split the cases, swap the 5 speed tranny for a 6 speed one (not the DP unit for the 620/750, but a stock unit from a dry clutch setup). This would give you a longer input shaft and allow the use of any dry clutch assemby without having to machine the hub down. I have no clue if a dry clutch 6 speed tranny will drop into the 620/750 cases, but I don't see why not. I would imagine there would be some more gear swapping involved though. I plan on doing a little more research on this and if everything points to it being possible I will probably try the swap this coming winter.
Update, on the option listed above:
just a note I don't believe the second option (900/sbk 6sp into the 750/620) in my post will work. Referring to BB moto one notebook...
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Brad Black »</TD></TR><TR><TD CLASS="quote">
The 6 speed gearbox from the larger engines won’t fit the small 2v engines, due to the shafts being slightly further apart. The new 6 speed gearbox from the 800SS/M engines will fit, and is much the same as the 6 speed gearbox from the 400 engine I am told. Ducati Performance is also offering
But when I split the 620 cases, probably this winter or later, I still try a 748 tranny to see what the issues are. Of course if on of you guys are splitting the cases and have a 748 tranny around, let us know.
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