Exhaust pipes mount

[backleg]

Hi,

I needed to loosen the exhaust pipes on my 2010 ST from the engine where one of the four studs broke. I wanted to remove the stud the usual way with bolt extractor but during rotating it counterclockwise the extractor expanded the stud remains and cracked the threaded hole on the engine.

How would you fix this? I guess I need to go to a professional to weld the crack and inser a thread insert as I'd need a tig welder.

Thank you for your help in advance!

Best regards

 

[TenereGUY]

Good luck. Maybe they can help but it may come down to a new head.

 

[backleg]

After initial panic I looked at the damage once more and realized that the crack is quite short, like 1/5th of the thread's length. I think it should work with a thread insert.

 

[Cycledude]

Will be interesting to see how everything turns out

 

[Bridgee13]

All the best, I will probably come across the same snapping off stud issue when I come to change my downpipes.

Dave

 

[cyclemike4]

I hope your repairs go as well as they can. that is a big problem if it isn't done right. On a fun note. My buddies boy had an old warrior four wheeler years ago and the head broke right where the exhaust studs were. He had nothing holding the head pipe in. The old bike was good enough to ride but not good enough to buy a head. He built a plate that was bolted to the frame in front of the motor. He angled the plate to match the exhaust flange. then threaded it and put two jack bolts in it that pushed on the flange from the frame. It held for two years! then he got a Raptor and moved on from the warrior.

 

[backleg]

Thank you all! Luckily the mounts are well separated from the head so any crack would have hard time to continue to the head.

With even closer inspection I realized that the damage is bigger than just 1/5th of the thread's length. There is another crack of around 1/3 to 1/2 of the length but just where the mounts are the thickest it is still intact.

It was very hard to drill accurately as the beginning of the hole is deformed, expanded. The stud remains inside the hole made it even harder. I tried to shape the initial opening with a mini grinder so that the drill would more easily continue straight into the old hole. It was a big challenge. The new bigger hole is not perfectly centered but I think it should be good enough. It is perhaps 1mm off. Now I'm waiting for the time sert delivery.

As the thread tap cannot cut all the way to the end of the hole I'm now planing to grind away the tip of the thread tap so I can hopefully cut a correct thread all the way to the end of the hole. Then insert the time sert, lock it with permanent Locktite and fill the cracks with JB Weld extreme temperature.

 

[Cycledude]

Pictures would be interesting.

 

[Wymbly1971]

They do sell bottoming taps...thread to within about 1/16" of the bottom of the hole. I would caution grinding a tap. If you weaken it and it breaks inside the hole you are in for a whole world of trouble. Keep the grinding as cold as you can.

 

[backleg]

Good point, thank you! I'll take some pictures next time I'm in the garage.

 

[backleg]

Hello,

Here come some pictures:

Time sert was successfully inserted. In fact half of the thread length was cracked but fortunately the thickest half was healthy.

Then I wanted to bend in the cracked part and reinforce with metal paste but the cracked part fell out instead.

Now I covered the opening with the metal paste. It's more for "cosmetics" but we'll see if it holds anyway.

 

[backleg]

Dried and painted. Now I'm waiting for the shock that's being renovated.

 

[backleg]

The original shock renovated! As I read that it could be done I convinced a guy in Sweden that he could do it and he did. And he confirmed that the shock is actually of good quality. It doesn't deserve it's bad reputation.

Anyway, the exhaust is also back in place. I only needed to grind away some material, among others enlarge a hole in the big washer for a tiny bit. I haven't tested neither the exhaust nor the shock yet, though.

 

[backleg]

Last update: it works well, tight with no leakage!

Lesson learned: in this case it would be more appropriate to drill out the broken stud in the first place.