[h2omonkey]

I have a buddy with an gt who found a hairline crack in the front motor mount boss. He said someone told him it could be fixed with helicoil, but isn't that for just fixnig threads? What are the options on this? Thanks.

 

[Cesare57]

Is his bike still under warranty? If so, he should take it to a dealer.

 

[Lee C.]

Threaded insert brands like “Helicoil” and “Keensert” are for fixing stripped threads.

Have a shop check out the motor mount, it may be just the case paint that is cracked.

Lee C.

 

[h2omonkey]

The bike is out of warranty. Probably no dealer involvement. Thought someone on this site might have an answer for this, seems like a pretty common thing to happen on the trellis frames during a get off, searched all the forums with no luck.

 

[ps1k]

if its one of the frame mounts on the motor you cut them down beyond the crack and build a spacer to replace the area that is missing.

i can get you some pics of one of my motor after we did it if you'd like.
befor emy computer crashed i had some of the before pics.

could you send me a pic of the damage?

 

[bpracer]

Or, have a "good" welder, weld up the crack and then use a heli-coil to repair the threaded hole after the welding distorts the old hole. Finding the end of the crack would be important. In a perfect world you would use a mill to align and re-drill the mount.

 

[ps1k]

i can't think of a motor mount on the DS motor that is threaded

 

[bpracer]

Good point!

 

[PrimoMoto]

The bike is out of warranty. Probably no dealer involvement. Thought someone on this site might have an answer for this, seems like a pretty common thing to happen on the trellis frames during a get off, searched all the forums with no luck.

You are correct: it is fairly common with the trellis frame when using frame sliders.

I'm fixing my Sport 1000 right now for this very problem. Mine was the result of a huge highside (racetrack) when my front touched the rear tire of a rider I was overtaking at about 90mph; I went sky high and the bike did the ol' launch... (wait for it)... end over end thing... it was messy! Broken collar bone and six weeks later I actually didn't realize the motor mount was cracked until after I had repaired everything else. I was cleaning what I thought was a hairline of grease/oil only to realize it was indeed a crack, then upon close examination saw that it ran all the way across the engine, across both case halves. Bummer.

In my case (pun not intended ) it turned out that what looked like a hairline crack was much more severe. In fact when we split the cases, a 3" long chunk fell off!

The only fix it is to disassemble the engine and have the cases welded. This absolutely must be done by a qualified welder! The shop that did mine is an aerospace machine shop who happen to be moto racing enthusiasts, so they really care about what they're doing. He pre-heated the cases prior to welding and did only a small amount at a time. He did the job over the course of the day so as not to warp the cases.

I don't know where you live, but if you can get your case halves to Phoenix, the company is called Superfinishers. if you need it, I can track down contact info tomorrow.

Also, I spoke to Mark Sutton at Ducshop near Atlanta, and he told me they repair four or five a year. You can send the cases to him.

A side note is Mark does not recommend frame sliders because of this problem. Ironically, I had heard that advice way back before my big get-off, but ignored it 'cause I thought the frame sliders looked cool! I won't be running frame sliders anymore (even though they do look cool ) baecause the tank got all banged up anyway, so between that, the clip-ons and rear-sets, it can just slide on those! This is probably a topic for another thread...

Anyway... DO NOT mess around with this problem. It is potentially life threatening. The engine is a stressed member so if it were to come loose, even just a little bit, could make for a lot of no fun! :eek

Too bad I didn't have a camera handy when we split those cases. You guys wouldn't believe it! The new weld job looks sound, but as the man who welded it said: "It should hold up, but it is NOT a new case." :think:

 

[ps1k]

3" holly [email protected]

mine have all been very short, say less than 1/2"

if its just the lug it can be fixed just like mine.

either way the motor has to come out and you can inspect it much better without all the other crap in the way.

 

[PrimoMoto]

3" holly [email protected]

mine have all been very short, say less than 1/2"

if its just the lug it can be fixed just like mine.

either way the motor has to come out and you can inspect it much better without all the other crap in the way.

Yep 3 or maybe 4 inches... went all the way to the case split, however long that is. Guess it was a hard crash. Sure felt hard! :crazy:

Note to self: NEVER target fixate. Always SEE the way through!