Just finished upgrading my 14' XTX jack shaft to the 17' jack shaft and bearing. I had just over 9,000 miles on the original bearings and figured it's time to do the upgrade. Everything was original in the chain case except for the upper gear bushing. I found a jack shaft off a low mileage wrecked Sidewinder super cheap and ordered the rest of the parts from Yamaha. The job really wasn't to bad. I couldn't get the threaded collar to break loose under the gear so I used Cannondale's recommendation of using a bearing puller on the clutch side to pull the bearing and aluminum support first and then tap the bearing out the chain case side with the shaft. The only thing that's different with the newer 17' setup is as far as I could tell is the bearing is narrower which requires coming up with a spacer to add to the bearing housing to make up for the extra 4mm gap. I found a couple of large c-clips at the hardware store that fit. Really the only reason you need them would be if the bearing ended up moving over in the housing. Other than that everything assembled and seemed to line up just the same as the 14' setup except this new setup up will be a lot easier to change bearings when the time comes. I've attached pics of the 14 and 17 shaft lined up, the parts I replaced, the c-clips I used as spacers in bearing housing and the assembled unit.