Broken engine studs...*again*

[Standard Issue]

Well folks, like the title says...my motoredbike is OOC for the time
being, due to broken engine mounting studs.

The first time only one of them broke. I removed it, bought better
quality studs, replaced both, applied loctite, and even put some
bits of innertube rubber between the mount and the frame to dampen
some of the vibration.

Unfortunately, it was all for nothing, it seems.

75 miles later, BOTH of the rear engine mounting studs broke off.

What a drag! I mean, I know these things have a tendency to shake
themselves apart, but this is ridiculous!

Has anyone else experienced this, and/or have a work-around?
I refuse to just remove the broken studs, and replace them again
only to have the exact same dang thing happen to me again in
another 75 miles!

 

[JosephGarcia]

Heli-coil the threads, and buy new grade 5 or 8 hardware?

 

[Guest]

Are you sure something isn't binding or pulling sideways a bit? I replaced mine before I ever built the bike with grade 5 hardware, and used loctite high strength sleeve retainer on them, 200+ now with no problems.

 

[gone_fishin]

i revived this topic in general discussion because it's obviously a "keeper" ...i know it's too late this time, but the "strange noise" clue could be helpful in the future.

based on my brief experience: you have to learn your individual bike's "cycles" and maintain it accordingly.

http://www.motoredbikes.com/viewtopic.php?t=1237

 

[spunout]

broken mounts

are you careful not to over-tighten the dogs#*t out of the studs/nuts?

 

[locoWelder]

get rid of the rubber you put in there, by putting it in you made cushin in the mount that the motor was not made to run with , you made room for it it to torque to one side.
now if the studs are broke off in the engine case tap them out and retap them to 8mm the standard 6mm will keep giving you trouble.

keep in mind that the case is pot aluminum do it slow and with lots of cutting oil.

 

[Standard Issue]

Thanks for the suggestions folks.

LocoWelder, I think you may be right. The rubber mount I made had
started to wear through, and it probably was allowing the engine to
move around a bit.

I will replace those studs with larger, 8mm studs as well, once I extract
the old broken ones. I really hate doing that, as broken stud removal
can be a bit of a dicey operation, where everything has to go *just right*
or else you've just made the problem a whole lot worse!

Wish me luck ya'll

 

[locoWelder]

If you have a machine shop near you go to them , they should not charge you more than 20.00 for two holes and if they mess up they pay for it but take your mount boot with you it will need to be done as well.