later transmission work in a 72 256 xs650 engine

[TwoManyXS1Bs]

There's a lot of good threads and videos in here on clutch servicing. Pay close attention to the shim washer thicknesses and reassembly order, plus the friction/steel plates stackup height.

That needle bearing washer isn't a throw-out bearing. The throw-out forces are in the mainshaft's double-row bearing (just behind the clutch), and in the clutch pushrod/bearings. But, it does help to control the clutch basket's axial positioning during clutch disengagement.

Use the 4-page bulletin in this post to check internal spacings:

http://www.xs650.com/forum/showpost.php?p=314254&postcount=11

 

[Paj]

Hey, XSLeo! Yes, there was an obscure change to the mainshaft needle roller bearing starting with the early XS1, S/N S650-001235. The needle bearing OD changed, and this was accomodated by a change to the bearing pocket in the cases. The mainshaft remained as-is. A serious heads-up to anyone working with the early cases.

The BIG change occurred with the 1972 XS2, where the first gear ratio was changed, along with the kickstart gearing, which uses the 1st gear.

***************************************
XS650 transmission evolution
(work in progress)

*** Starting 1970 XS1, 256-parts

1st gear: 14t mainshaft, 31t countershaft, 26t kickstart
26/14 (1.857:1) kickstart ratio (See INXS thread on Kickstart)

*** Starting 1970 XS1, 256-parts, after s/n 001235

Change to mainshaft needle bearing OD, only cases changed.

*** Starting 1972 XS2, 306-parts

Change to 1st gear ratio
1st gear: 13t mainshaft, 32t countershaft, 25t kickstart
25/13 (1.923:1) kickstart ratio, harder to kick (See INXS thread on Kickstart)
Changes to shiftdrum, interchangability unknown. (to be done)

*** Starting 1977 XS650D, mid production at 1T3-721262

Changes to splines of both shafts and ALL gears.
Old shaft/splines have polished valley bottom.
New shaft/splines have polished spline tops.
5th gear shaft OD changed from 0.979" to 0.975"
5th gear wheel ID changed from 0.984" to 0.979"

Some changes to other parts, bearings and shims. (to be done)

Hi TooMany
You indicated the splines changed around mid 77 and up, were these changes made across all 650 motors or just the 256?

 

[gggGary]

Hi TooMany
You indicated the splines changed around mid 77 and up, were these changes made across all 650 motors or just the 256?

(70-71) 256-no e.start
(72-73) 306-with e.start............Both these have conrods @ 135mm labelled 256

(74-84 USA) 447-with e.start............Conrods are 130mm labelled 447

(74-83 europe) 533-with e.start............Conrods are 140mm labelled 533

 

[Paj]

(70-71) 256-no e.start
(72-73) 306-with e.start............Both these have conrods @ 135mm labelled 256

(74-84 USA) 447-with e.start............Conrods are 130mm labelled 447

(74-83 europe) 533-with e.start............Conrods are 140mm labelled 533

Thanks gggGary.