note...this is part 1 of a 5 part summary that i put together in order to understand a little about XS650 clutches...i have used photos in this series that i found on the net as well as my own - if anyone recognises theirs let me know and i will post credit for it - all accept my thanx for the use of...the information here is not what i would call complete so please if you read this and disagree, have some info that will extend this, or comments, post them... lets see if my experiment with attachments works...well i see it wasnt quite successful but ...... 1. Yamaha, the timeline: Well, I donâ€™t know much about clutches but nevertheless here goes. In the beginning there was light, hot burning searing endless light and then god made bikes, in all concievable sizes and shapes and there was joy for noone, as noonne was there and he could choose endlessly between them. Problem is all he knew about clutching was how to grab his balls trying to stop them falling through the sun during one of those oh oh WTF moments. Just as well there were so many bikes. Trouble was not only were some nicer than others to ride but eventually it became difficult to find one that worked properly. Damn! Time to bend my head around shit. Take the XS650 â€“ basically 3 different clutch set-ups The clutch was always a weakness. It never really handled the power, requires close monitoring. There are common complaints wrt engaging gears, slipping, oil sensitivity, neutral finding, sticky clutch and adjustment issues. The clutch engages quickly and as Yamaha didnâ€™t provide rear-wheel-dampening, shockloads the gearbox and the dampening springs built into the primary drive gear behind the clutch basket â€“ eventually they break (models between aug73-aug79 being the worst effected). Problems must have begun right from the beginning. The XS1B received: different springs, the cushion rings between plates, a thrust washer between the needle plate bearing and the boss, a new worm gear and adjuster. A redesign for the TX650A dumped the cushion rings in favour of thinner and more friction plates (+1), new washers for the boss nut, new boss part #, a 2 piece push rod and an extra 5/16â€ ball bearing. Result? Increased risk of primary drive dampening spring damage. Aug â€™78 saw futher changes. Back to 6 plates, but with a new clutch package-a set plate, cushion spring and clutch plate all held in place with a fitting ring, the boss receives yet another new part # and a new fixing washer and lock washer, the new 2 piece push rod is swapped about so the longer pierces the seal (presumably to give more support and less seal wear) and the worm gear was further modified bringing the pull point closer to the center of rotation. 1.1 pdf Yamaha themselves havenâ€™t helped. They misprinted their first manuals, leaving 1 Thrust Plate off the Part Breakdown and Part Listâ€¦there should be 2 of them. 170-16164-00 PLATE, thrust 2 (25-50-2)â€¦..1 93341-23504 BEARING ______?_____ PLATE, thrust (35, 51, 0.5)â€¦.1 Not only did they not bother correcting this, they perpetuated the error in subsequent years. What were they thinking? 1.3.1 gif XS1-TX650 clutch 1.3 gif pre â€˜78 clutch breakdown TX650A on 1.4 gif Late model clutch breakdown 1.5 pdf - Pressure Plates were also altered, with the addition of a spline, helping load spreading.