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i believe the injected cranks are different on the stator end. what about the st2?
 

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The early 900 cranks have a different spline on the flywheel side.They changed to a finer spline and a longer shaft around 94 I think.
 

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i believe the injected cranks are different on the stator end. what about the st2?
ST2 has the single-phase alternator so is like a 900 SS/Monster in that it has the woodruff key fitment for the flywheel however it has (2mm) bigger pistons so may be balanced differently?

3-phase electrics were used on later (ie) models and I believe the crankshaft end has splines rather than woodruff key.
 

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The crank changed to accomodate the 3 phase stator which also came at the same time as the switch from carbs to fuel injection. I think these changes were in 1999
 

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this is from one of my reports. i think the changeover to 3 phase alt is 98 on air cooled motors and 99 on water cooled. the 98 900ssie manual shows the 3 phase, 98 st2 shows single phase, 98 916 was single phase, 98 updated little motors (600, 750) were 3 phase.

Cranks vary with alternator width (900SS up to ’92 and ’92 – ‘98) and type (’99 on).

The up to 99 models ran the single phase alternator with the magnet rotor spinning inside the stator. These alternators have 2 yellows wires going to the regulator.

The single phase alternator has two different width rotors. The narrower rotor was fitted to the small blocks (600, 750), 900SS/SL up to engine number 006908, early 851, 851SP, 888SP and the ’97 ST2.

The ’99 on 3 phase alternator has the magnets in a large dish style arrangement that spins around the stator. These have 3 yellow wires running to the regulator.
As far as I can tell, any ’99 on crank will fit any of the bottom ends similarly.

The 900SS/SL cranks got wider in ’92, from engine number 007089. The 900SS/SL parts listing says up to engine number 006908 were narrow and from 007089 were wider. I have no idea what happened from 6908 to 7089. The 900SS/SL alternator covers vary in width accordingly. With a wide cover on a narrow crank the end of the crank misses the crank end bearing by about 6mm. Fairly obvious.

The pre ‘92 900SS/SL 68mm cranks will go into the small engines and have the same 6 spline flywheel mount. Although you will have to machine the timing shaft to clear the rods.

The ’92 on 900SS/SL cranks are 18mm longer at the alternator end and have 15 spline flywheel mountings. They also have larger timing gear mount diameters. Same engine
numbers as above for these changes.

All other large block single phase alternator cranks are the same width – 906, 907, 851 ’89 on, 888, 748, 916, 900M, ’97 ST2.

The 906, 907 and ’89 – ’91 851 cranks have the 6 spline flywheel mount. Although the 851 SP2 and SP3 have the 15 spline I believe.

The ’92 onwards engines had the 15 spline flywheel mount and are larger where the timing gear sits by about 5mm from memory.
 
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