I went to Highland Park riding resort, the site also of KTM World, in Cedartown Georgia and rode the '77 MC5. As many of you have read, I am not happy with the suspension and was going to replace the 5W shock oil in the shocks with something of higher viscosity. The last ride of the day, the right shock came apart, the big nut at the bottom of the body that you unscrew to remove the shaft and internal parts backed out. Amazingly, I did not even know it had come apart while riding, it felt no different than while both shocks were working. Also amazingly, it does not appear that anything is damaged in spite of unknowingly riding with the shock broken.
Anybody ever seen this? These nuts were SO hard to get apart when I rebuilt them I did not want to put any loctite on the nut, but it was NOT loose. Its been almost 18 months since I rebuilt them, and lots of miles so its odd that something would happen now. I'll got get a picture right now and maybe pop the shock off and see what, if anything, is damaged.
Brian
Sorry for the dirty bike, I didnt have time to wash it. Pictures:
(http://i1177.photobucket.com/albums/x348/kartwheel68/07182011117.jpg)
(http://i1177.photobucket.com/albums/x348/kartwheel68/07182011118.jpg)
Once I got it off and inspected it, there appears to be no damage at all, the big nut/cap screwed right back into the shock body and the fine threads have no damage. Just a little clean up, new oil and it will be fine. One thing I did notice though, the soft black rubber bottom out bumper that comes with the rebuild kits is totally inadequate for an offroad bike. It may be fine for a road bike where the shock will not get bottomed very often, but the bumper has been pounded to bits on this bike. The outside looks fine, but the center of the bumper has been hollowed out and deteriorated to the point that its not functional anymore. It looks like there needs to be a thick steel washer between the bumper and the bottom shock mount. This is not a knock on the kits Rod sells, I suspect they are made for road shocks, I just thought folks might want to know. I'm going to see if I can find some urethane bumpers off something modern that will work. I'll post here on what I find.
Brian
Looks like the bumper for a '02-'10 KX85 is 12.5mm ID and should work perfectly with some trimming since its for a single shock and will be too tall. That and a good thick backing washer should do the trick.
Brian
Brian,
I used to rebuild Marzocchis back in the 70's and 80's. I don't recall using loctite when we rebuilt the shocks either. Guess I'd use a little blue now.
That's pretty wild - but then anything CAN happen. I had a circular polarizer completely unscrew itself from my camera & disappear on a hike last week, and it had about as many fine threads.
If you are hitting the bumper hard enough to bounce the nut loose maybe you really DO need a set of stiffer springs.
You just never know.......
I think its from the vibration of the 400. That thing vibrates sooo bad, and I religiously check all the motor mounts, stays, swingarm bolt and the cylinder studs/nuts. It really needed stays going to the cylinder like the Maico's have instead of those going down to the cases. I am thinking about making some stays for the cylinder.
Brian