Speedmaster Exhaust Header Bolt Snapped, Anyone Familiar With These Bolts??

Picture would help. Not sure what is meant by “snapped” after reading your description. If it’s a stud and a nut and one stud stays in the head and one comes out it’s not abnormal. Probably need to put some wd40 or equivalent on the stud staying in and clean the threads on both studs. Nut should come off on both cases easily.

 

Description still sounds confusing. If if the stud with the bolt rusted on has just unscrewed from the head then you're in luck. Does it screw back in if you try with your fingers? If so, and you can separate stud and nut, you can reuse them; otherwise they'll need replacing.

If the stud has sheared off, it will have left an end stuck in the head and will require drilling out and fixing with a helicoil or similar. This is very tricky. You will also need a new stud as well.

I bodged my way out of a similar situation many decades ago by drilling out the sheared stud with a bigger sized hole, tapping the hole. Then I took a bolt of that size and filed the end down to original stud size and threaded that. It didn't work great and I darn't torque it up much past finger tight. Of course the next time I came to remove stud, the nut had rusted on and I ended up just removing the stud from the head.

 

Sometimes you can drill in the center of the sheared stud with a much smaller drill and use a tool for removing sheared studs out. There's probably a name for it, but at the moment it escapes me. If it was my choice, I would remove the head totally so it can be worked on off the motorcycle.

 

It's called a stud bolt extractor. They come in sets of small to bigger studs. It's worth a shot. Your next choice is doing the heli route. I'd try to take it out carefully and save the threads.

 

Research extractors. With that much sticking out you should be able to get it out. I'd still remove the head. Those threads on the studs look pretty messed up. They may have installed ones with the wrong pitch when someone previously had them off. The exposed threads in the head look damaged too.

 

I recently had to deal with a snapped bolt, and googling use of these extractors led me to some people having problems with these snapping of (because they're hard and brittle) and then having difficulty drilling out this hardened extractor. I decided it wasn't worth the risk trying to use one.

 

Best way to remove is to weld another bolt to the snapped stud. The heat then travels down into the head from the broken stud and eventually breaks down the seized thread, add some diesel to it and it always works. That’s if you’ve a welder……

 

Risk involved always. Heat helps and there is enough of the stud there to have options. I suspect it’s pretty solidly in and most likely the pitch is wrong and the threads are messed up in the manifold as well. There are options with various types of thread inserts if the threads can’t be cleaned up. First thing to do is to find out what should have been there to begin with. From what I’ve heard from people more versed than myself is the Brits had a variety of standards used before getting to standardized metric threads. I suspect someone forced metric threads in one of the British standards prior to going metric. Be careful that what you do doesn’t make greater damage.

 

Motone manufacture replacement studs for 2016> WC twins (if that’s what you have) if you get stuck. They’re stainless so apply copper slip on the threads before insertion.

 

Recent Triumphs would be metric. Somehow I thought this was a slightly older motorcycle. At any rate go carefully, it doesn’t look like someone was careful before you.

 

From online parts diagram, it looks like an 8mm thread and same stud part number (T3100015) used on about a 100 models of Triumphs. So presumably very easy to get hold of.

Edit: As well as being in stock at the usual places, Square Deals do a stainless steel version with nut, though I believe stainless has less strength than usual steel bolts? (But not rusting in the first place is a major plus).

 

Heat should allow you to remove the broken stud, the tap and fit new studs (depending on how much meat is left in the stud hole)

 

Looking at the photo of the broken stud in the head I would try the following first, clean up the thread as best you can, get 2 8mm nuts and run one down the thread as close to the head as possible, then run the second nut down on the first, tighten up the bottom nut onto the first tightly, soak for a while with penetrating fluid (plus gas or similar) then get some heat around the area (not directly to the stud) then slowly try undoing the stud using anti clockwise and clockwise motion until you detect free movement and then extract it fully, it looks like the thread is damaged in one of the photos were you have removed another stud, hopefully it will clean up with a tap. The stud on the downpipe is easy sorted, cut it off as close as you can to the down pipe, then either centre pop or drill it out. I would not recommend using stainless bolts into an alloy head, as chemical fusion takes place over time effectively welding the two together, what you can do if you really want to use stainless stud sis to use a military grade stud locking fluid, this is effective at extremely high temperatures (more than your engine will ever produce) then when set (usually within 24 hours) you can then use stainless nuts to secure the down pipes, if you ever want to remove the studs you will need to apply extreme heat (oxy torch), this stuff sets very hard, it's like Loctite on steroids.

 

Careful use of heat is your friend with most seized bot/nut/stud situations. With the amount of stud you have left sticking out, welding a nut on the end would be my first option. If it shears off flush, drilling out with a small left hand drill bit can work followed by and extractor if it doesn't. For the studs that came out, I'd also clean out the threaded holes with a thread chaser, not a tap. Decent access is usually the biggest problem in situations like this.

 

It should be noted that 8mm threads come in several different pitches, so you need to check that the nut matches the stud. (I recently discovered this when getting replacement bolts for my bike.)

I ended up buying tools for cleaning up threads. These are tighter fitting that nuts and bolts, but aren't as sharp as taps and dies, so you don't risk cutting a different thread.