[SBK Project: 2v Motor - 748/996 era Frame]

[caperix]

The 2 resesed teeth on the timing sensor is what the sensor picks up.  The dot on it is for timing it with the crank gear.  Not sure about running aftermarket spark control off it, but it does run at cam speed so the sensor only picks up its reference point every other crank rotation.  There are some on this board who have run 1000ds's off carbs so maybe they can chime in on the ignition.

[junior varsity]

Sweet. The thread I linked to off .MS was saying something similar. I should be able to figure out the wiring and get it connected to an Ignitech box. That's pretty far off into the distance, but good to know that it should be possible in the meantime.

Up on deck is figuring out how to get this motor into a SBK frame. A 748 superbike frame and swingarm. (That's what I can get my fingers on in pristine condition for cheap.)

Silly question, but back on engine cases...

Besides the swingarm mounting distance "width" - is there any difference in the location of motor mounts between the air cooled bikes and the water cooled bikes? I didn't think so, but now I'm concerned after an email I received (shared below).

I'm measuring, from rear/top motor mount center to swingarm pivot center, approx. 100mm. From swingarm pivot center to rear/lower motor mount center, I get approx. 110mm.

Anybody have a 748 motor laying around that could verify that?

The frame I'm getting is an 02/03 748 (I thought they ended in 02, with 03 being the 749, but its listed as an 03). Fixed headstock (fine with me).

Here's the email that troubled me: [my commentary is bracketed and white obviously]

You need to mount the motor in a mill and cut 15mm from the left side of the motor and 20mm off the right side.  You need to basically cut off the outer bearing area where the swing arm pivots in the motor.  There are 2 bearings in each side of the motor.  remove one from each side and machine the motor to fit the swing arm. You can install the swing arm into the SBK frame to get a total width measurement and cut the motor to fit.  [that's what i thought so far...] You will also need to move the upper rear motor mount to line up the bolt hole.  It will be about 8mm off.  [what?] You will notice in the pic that the rear mount hole is the same size as the swing arm one.  It is the same as the front hole stock. [yup... but i thought the 748 mounting holes were the same front and back also...] You will have to make a custom exhaust.  [of course] I made everything myself at home.  The bike in the pic is all ready to run with all electrical done just need gas to run. You can see by the color of the pipes I have already run the motor. [stop bragging]

[1KDS]

Who wrote the email?
Where's the pic?
I have a 748 frame in the garage and a SS900 motor that were once one.  The only modification to the frame was the X brace near the airbox to clear the TB's.  Not sure what he is talking about when he's talking about moving the motor mount.

[junior varsity]

http://www.duccutters.com/Hull-944Corsa.tpl





His motor is older than mine, likely his frame is as well. I picked up the frame today (and swingarm and shock pivot).

Fun story goes here:

The frame is a 2003 Ducati 748 Frame. That's right, an '03 748 frame. They didn't import 748's to the US in 2003, we got 749's. But an american pilot picked this up at the factory and brought it home. Its never been registered, came with all original paperwork.

Swingarm is a standard 748 style swingarm, same with shock pivot. I've got a few more things on the way so I can mock it up and see where the issues lie.

[1KDS]

Nice! I never looked at that build before.  Still not sure what he's talking about on the motor mounts.

[junior varsity]

I think I'm seeing the issue as I use an old spare frame bolt for the front, an SS swingarm pivot bolt through the frame and motor pivot. Looks like the motor mount is just a smidge off - should be up and forward slightly.


I'll take some pictures. Time to start the brainstorming.

[junior varsity]

Meanwhile, back at the ranch I was removing things from the sides like the oil pump/gear (just 3 bolts - probably the easiest thing to remove yet), and then pulled the flywheel/starter sprag (done, absolutely still a pregnant dog).


Anyhoo,

As I turned the motor to get ready to remove the flywheel nut, i spied on the work bench, a huge ass ball bearing. I mean, the sucker's gotta be 3/8" in diameter, SS ball bearing. where in the crap could this have come from? Would it be a part of the oil pump assembly? I didn't disassemble that pump, just pulled the three bolts and wiggled it out, set it aside (bagged it, tagged, it and boxed it).

[Speeddog]

Check the main bearings on the crank to see if it came from there.

Oil pump doesn't have a big ball in it.

[junior varsity]

i figure that's where it came from. Can't believe the vibrations from an impact wrench let one just... "fall" out. (especially without the rest pouring out after it)

Guess I'll know when I split the cases.

[ducpainter]

i figure that's where it came from. Can't believe the vibrations from an impact wrench let one just... "fall" out. (especially without the rest pouring out after it)

Guess I'll know when I split the cases.

My 750 died from a main bearing failure...

in that case the cage disintegrated allowing the balls to roam free in the races leaving a large space for the crank to move up and down.

Wouldn't surprise me if that 900 had the same issue.

[Speeddog]

You don't need to split the cases to see if there's a ball missing from one of the mains.

[junior varsity]

just have to remove the gears that run on the crank?

This is my first go at doing motor internals, so I'm taking everything slowly.

[junior varsity]

hey.





that bearing ain't cheap.

[Speeddog]

hey.

that bearing ain't cheap.

[junior varsity]

Ha. I know. old news.

Perhaps I can get "Bearings Bonanza" pricing, since I'll be getting... pretty much every bearing.


Looks like I'll be trying to migrate all the 900 2v internals over to a 748 set of cases per Brad Black's suggestion - hopefully it will all work out. no machining to cases involved then for use in a 748 frame.