| Author | Message | ||
     Rob_c |
rear engine mount failed. cracked around the cap screws holding it to the engine, anyone else had this problem? | ||
| Aptbldr |
Bummer. I wanna see; got pictures? What's odometer reading? | ||
| Froggy |
I know of only one other person that got a rear mount to fail, and it wasn't fun to fix from what I heard. | ||
| Ochoa0042 |
yea on my engine rebuild i noticed that mine was broke.. hard to explain my catastrophic failure of the mount, but it was not on the four mounting bolts to the engine like you were saying.. you're gonna have to drop the engine to get to it +1 show some picks | ||
| Hughlysses |
I saw one fail at March Badness II, resulted from a crash where the bike low sided and went backwards into a small ditch on the inside of the curve. The owner rode the bike back ~10 miles to TWO without realizing the mount was broken. We were looking at the bike later and just happened to notice the problem. We managed to swap one from another bike (graciously provided by Stone Mountain HD/Buell) and it was NOT easy. It's a VERY tight fit to get an allen wrench to go into the mounting bolts into the top of the cases. A ball-end allen wrench of the right size should work. We used a combination of needle nose vice-grip pliers and some sawed off regular allen wrenches. IIRC we disconnected one end of the rear shock, disconnected the rear tie bar, then we stuck a log between the back fender and the rear tire to support the rear of the bike. That gives enough clearance to get the old mount out and the new mount in. The hardest thing about the swap was getting the bolts out. (Message edited by hughlysses on November 28, 2009) | ||
| Hughlysses |
Photos of the swap on U4euh's bike from an old MB thread: Removing the new mount from the donor bike:    U4euh's bike prior to the lowside:  Erik himself walked by a couple of times when we were working on the bike- that was pretty cool. | ||
| U4euh |
That was me and it wasn't fun. The 3% were the best at that event getting me up and running. Best part was Pete the farrier saying he would like to meet the damn engineer who made the bolts the way they were, everyone told him to turn around and look behind him. To which Erik just smiled, PRICLESS! | ||
| Rob_c |
The bike had done 16000km when the engine mount broke, it weaved down the road for 100 metres before it left the road. attached photo's of mount  | ||
| Hughlysses |
That's pretty much what U4euh's mount looked like. So Rob- you think the engine mount broke and then you wrecked? | ||
| Swordsman |
"Best part was Pete the farrier saying he would like to meet the damn engineer who made the bolts the way they were, everyone told him to turn around and look behind him. To which Erik just smiled, PRICLESS!" LOL! That's hilarious! So, did Pete ask, "Hey, WTF is up with the bolt placement?!" ~SM | ||
| Socalbueller |
The rubber failed on my rear isolator and it was a pain in the ass to replace. They could have made the base a little wider so the allen bolts were not underneath the rubber bushing. I had to get a stubby allen wrench to get them out. While it does a decent job on vibration control of the engine I question having 2 big globs of rubber between the swing arm and the frame. | ||
| Hughlysses |
So, did Pete ask, "Hey, WTF is up with the bolt placement?!" That's Pete lying on his back in photo #2 in my post above. If Pete didn't ask it in the daylight when Erik walked by, I'm sure he asked it more than once by the time of that photo. IIRC, we had a rotating crew working from about 4 PM that afternoon until about 10 PM that night. I had to ride my S3 ~15 miles back from TWO to the Motel Hell in Dahlonega afterwards. The temp was a wee bit "brisk" at 10 PM in March! | ||
| Rob_c |
Yes, mount broke first, bike basically ok apart from bent front wheel when it hit a rock. classic fatigue failure. | ||
| Killroy134 |
This happened to me 2 weeks ago, got into the front wheel and wrecked me at 60 MPH. VERY BAD! | ||
| Hogs |
Really can`t see How these mounts Break??? However I know they Break when ya lay the bike down and Hit something that can break them, but besides that I don`t understand how you say it broke first then the accident??? | ||
| Jstfkndi |
Slamming down hard after stoppies! | ||
| Greg_e |
Guess I better check the one on my 9R, pretty sure an idiot rode it before me and I bet it did more than a few ugly stoppies on a really stiff suspension with a 200 pound rider. I take it from the pictures it is not easy to see this mount from the outside? | ||
| Rob_c |
The broken mount seemed to be due to Fatigue, as it was clear that the broken areas had happened over a period of time, one bolt at a time as some of the cracks went into existing cracks. the last bolt area to fail had bent first showing that the other three had already failed. | ||
| Rob_c |
Killroy - same thing happened here, engine fairing hit the front wheel, but speed was lower 80kph (50mph) | ||
| Hughlysses |
I take it from the pictures it is not easy to see this mount from the outside? Greg- it's not that hard to see, it's just sort of hidden above the transmission. You just have to make an effort to look at it. I can't really see this mount getting stressed a lot except in a crash, unless the mounting bolts work loose. Checking to make sure they're tight periodically would probably be a good idea. | ||
| Rob_c |
Hughlysses - its not stress that is the problem, it would probably be fatigue due to vibration. when we removed the broken bits all bolts where tight. The machined out recesses for the cop screws with their sharp transition would not have helped as this is where it failed | ||
| Rob_c |
killroy 134 - did you come off straight away or hang onto it for a while? | ||
| Rob_c |
Accident the same as Killroy's, engine fairing hit front wheel. I suspect that accidents were the mount has been found broken and people thought the accident broke the mount, have in fact been the other way round and the mount broke and caused the accident. I have calculated that the force required to break an undamaged mount the way ours did is 18 tons so you would have to wreck the bike to break the mount. | ||
| Killroy134 |
Yeah I also weaved down the road for about 200 yards before it took a hard right turn and went down. After looking at the mount it was fur sure almost completely broken. You can see the material that was still intact. The mount broke exactly like the one pictured above. The insurance said it had been wrecked before I bought it. I would highly recommend that if you go down you replace the rear mount. Just think if this happened at 100 MPH+... | ||
| Killroy134 |
By the way, the bike is almost completely fixed thanks to people from this board and the Buelletinboard. Thanks to all who helped. Still need to have the plastic painted though. I am hoping to test drive it next week. | ||
| Rob_c |
I am getting my mount checked out by fatague experts and will post result. suggest that mount should be replaced every 8000miles or 12000 kms | ||
| Bobbuell1961 |
So i should have replaced it 5 times already?i dont think so, i just keep an eye on it | ||
| Froggy |
Replace the rear mount twice a year? Yea.... Sure.... | ||
| Rob_c |
There has been at least one failure where the rider died, so check carefully. It appears that the lower cap screws go first before the upper , so if your bike is doing high distances check often and carefully. | ||
| Spacecapsule1 |
Thanks for the info Rob. Please let us know what you find. No need for froggy to inspect his. He'll have a new bike before then. |
