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techtalk:evo:engmech09n [2021/07/28 01:43] hippysmack [Replacement Rubber Options] |
techtalk:evo:engmech09n [2021/07/28 01:53] hippysmack [Worn / Rusty Pivot Shaft] |
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| If you pull the rear mount apart, you may want to inspect the pivot shaft for wear and rust. You can pull the assembly apart at the same time you change the rear tire. \\ | If you pull the rear mount apart, you may want to inspect the pivot shaft for wear and rust. You can pull the assembly apart at the same time you change the rear tire. \\ | ||
| - | {{:techtalk:evo:susp:rear_pivot_bolt_wear_by_cosmo_kramer.jpg?direct&300|}} {{:techtalk:evo:susp:rear_pivot_bolt_screw_wear_by_cosmo_kramer.jpg?direct&300|}} \\ | + | The pivot shaft has metal-to-metal contact on the shoulder where it pushes against the motor mount and all along the hole going thru the motor mount itself. \\ |
| - | The pivot shaft has metal-to-metal contact on the shoulder where it pushes against the motor mount and all along the hole going thru the motor mount itself. The groove in the pivot shaft to the right is from contact with the backing plate on the throttle side isolator. ((photo by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) The groove was most likely worn in by movement in the vertical axis (as the groove was on the bottom side of the shaft), and has nothing to do with lateral play of the swing arm. ((XLXF of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423&page=3)) Since the hole in the backing plate is larger than the pivot shaft, the backing plate is not supposed to touch the pivot shaft. However, this may be one of the things that happens over time as the rubber gets weak and moves around a bit more. It is an extremely tight fit going through the motor mount itself (machined shaft and mating hole). On the shaft below, there was no wear where the pivot shaft goes through the rear motor mount. The only wear was where the isolators contact the shaft with the heaviest wear on the throttle side. The witness mark was nearly all the way around the pivot shaft. On the clutch side, there is a very faint mark from where the rubbermount backing plate would be hitting the bottom of the pivot shaft (closest to the ground where the weight would be resting on). Dirt bike suspension bolts can be much worse. Enough wear will cause excessive play in the swing arm, and then the rear wheel will not track straight because drive belt tension will twist the swingarm so the tire points to the left. \\ | + | In the pics below, the groove in the pivot shaft to the right is from contact with the backing plate on the throttle side isolator. \\ |
| - | \\ \\ \\ | + | The groove was most likely worn in by movement in the vertical axis (as the groove was on the bottom side of the shaft). \\ |
| - | {{:techtalk:evo:susp:rusty_rear_pivot_bolt_by_cosmo_kramer.jpg?direct&300 |}} {{:techtalk:evo:susp:07_rear_motor_mount_22_by_cosmo_kramer.jpg?direct&300 |}} Water can get between the isolators and the pivot shaft and cause it to rust. ((photos by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) The rust will only get worse as time goes by (especially if you live near the ocean). ((XLXR of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) Rust can cause long term problems because it will eventually cause too much swingarm play. Guys who live in places like Florida will have rust problems sooner than the rest of us. You can sand blast all the rust off, use sand paper or a wire brush to remove the rust. Then coat the shaft with a good marine water proof grease. Paint will only rust through again. \\ \\ \\ \\ \\ \\ | + | And has nothing to do with lateral play of the swing arm. ((XLXF of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423&page=3)) \\ |
| + | Since the hole in the backing plate is larger than the pivot shaft, the backing plate is not supposed to touch the pivot shaft. \\ | ||
| + | However, this may be one of the things that happens over time as the rubber gets weak and moves around a bit more. \\ | ||
| + | It is an extremely tight fit going through the motor mount itself (machined shaft and mating hole). \\ | ||
| + | On the shaft below, there was no wear where the pivot shaft goes through the rear motor mount. \\ | ||
| + | The only wear was where the isolators contact the shaft with the heaviest wear on the throttle side. \\ | ||
| + | The witness mark was nearly all the way around the pivot shaft. \\ | ||
| + | On the clutch side, there is a very faint mark from where the rubbermount backing plate would be hitting the bottom of the pivot shaft. \\ | ||
| + | (closest to the ground where the weight would be resting on) \\ | ||
| + | Dirt bike suspension bolts can be much worse. Enough wear will cause excessive play in the swing arm. \\ | ||
| + | And then the rear wheel will not track straight because drive belt tension will twist the swingarm so the tire points to the left. \\ | ||
| + | Water can get between the isolators and the pivot shaft and cause it to rust. ((photos by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)). \\ | ||
| + | The rust will only get worse as time goes by (especially if you live near the ocean). ((XLXR of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) \\ | ||
| + | Rust can cause long term problems because it will eventually cause too much swingarm play. \\ | ||
| + | Guys who live in places like Florida will have rust problems sooner than the rest of us. \\ | ||
| + | You can sand blast all the rust off, use sand paper or a wire brush to remove the rust. \\ | ||
| + | Then coat the shaft with a good marine water proof grease. Paint will only rust through again. \\ | ||
| + | |||
| + | {{:techtalk:evo:susp:rear_pivot_bolt_wear_by_cosmo_kramer.jpg?direct&300|}} ((photo by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) {{:techtalk:evo:susp:rear_pivot_bolt_screw_wear_by_cosmo_kramer.jpg?direct&300|}} ((photo by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) \\ | ||
| + | |||
| + | {{:techtalk:evo:susp:rusty_rear_pivot_bolt_by_cosmo_kramer.jpg?direct&300|}} ((photo by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) {{:techtalk:evo:susp:07_rear_motor_mount_22_by_cosmo_kramer.jpg?direct&300|}} ((photo by Cosmo Kramer of the XLFORUM http://xlforum.net/forums/showthread.php?t=473423)) \\ | ||
| ===== Replacement ===== | ===== Replacement ===== | ||
