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techtalk:evo:engmech09a [2021/08/05 01:19] hippysmack [From the Service Manuals] |
techtalk:evo:engmech09a [2024/05/18 21:32] (current) hippysmack [From the Service Manuals] |
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| - Install rear mount bolts. | - Install rear mount bolts. | ||
| - Install the lower front mounts. | - Install the lower front mounts. | ||
| - | - Install the upper front mount | + | - Install the upper front mount. \\ It is not suggested to leave it off. It adds rigidity to the entire engine/frame structure (and reduces vibration). ((John Harper of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/203891-top-motor-mount)) \\ Tighten the bracket to the head before you tighten the bracket to the frame to keep from introducing any additional stress. ((aswracing of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/193620-crack-in-head#post4209755)) |
| - Install the top center mount. | - Install the top center mount. | ||
| + | |||
| + | ====== Motor Mount Pics ====== | ||
| + | ===== Upper Front Mount ===== | ||
| + | Here is how the upper front mount looks as installed. \\ | ||
| + | The washers in the 1st pic aren't OEM matches but as you can see in the 2nd pic, that's Ok. ((photos by Bryan1976 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/201174-front-motor-mount#post4454811)) \\ | ||
| + | * Factory bolts and washers: ((IXL2Relax of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/201174-front-motor-mount#post4454811)) | ||
| + | * Bolts (4716W) 3/8"-16 x 1-1/4" Hex Head - Grade 5 | ||
| + | * Washers: (6701) 3/8" x 13/16" x 1/16" | ||
| + | |||
| + | {{:techtalk:evo:engmech:motor_mount_upper_front_on_rigid_sportster_pic1_by_bryan1976.jpg?direct&400|}} | ||
| + | {{:techtalk:evo:engmech:motor_mount_upper_front_on_rigid_sportster_pic2_by_bryan1976.jpg?direct&400|}} \\ | ||
| + | |||
| + | ===== Cracked head at the front mount threads ===== | ||
| + | From aswracing of the XLFORUM ((https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/193620-crack-in-head#post4209755)) \\ | ||
| + | Unfortunately, this is not an uncommon problem. It was especially a problem on Buells, which don't have a frame under the motor and therefore those two bolts were supporting the entire weight of the engine. But even on solid mount Sportsters, these cracks happen sometimes. The top end of the motor grows with heat and the frame doesn't grow near as much, so this spot gets progressively more stressed. Add in a little vibration and you can see the result. \\ | ||
| + | |||
| + | The Motor Company pulled that bolt inboard on the Buell XB's in 2003 to get some more material around it and make it stronger. Then they did the same with the rubber mount Sportsters in 2004. So all the new heads have that bolt hole relocated inboard a little. \\ | ||
| + | |||
| + | I've seen people cause this failure themselves, too, by using a bolt that's too long for the hole. Once that bolt bottoms in the hole, continuing to tighten it just pushes the threaded portion away and causes the failure. \\ | ||
| + | |||
| + | As far as fixing goes, I've seen it hold up after welding, and I've seen it just crack again. So that's an iffy repair. The head needs to come off regardless and that vintage heads are generally pretty darn common and not expensive in the used market, so I personally would just replace it. But that's just me. \\ | ||
| + | |||
| + | {{:techtalk:evo:engmech:1996_883_head_cracked_front_mount_hole_by_slamtry.jpg?direct&400|}} ((photo by slamtry of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/193620-crack-in-head#post4209755)) \\ | ||
| \\ | \\ | ||
