u/Can_O_Murica

Part 1: https://www.reddit.com/r/sportster/comments/1t6oslo/shit/

Part 2: https://www.reddit.com/r/sportster/comments/1t7bbmr/shit\_day\_2\_electric\_boogaloo/

Part 3: https://www.reddit.com/r/sportster/comments/1t8jpok/shit\_part\_3\_electric\_beegalee/

Starting from the beginning to try and get the whole story in one place:

I was installing a basani mega power on my '07 XL1200 when the lower exhaust stud on the rear cylinder sheared. I tried heat and kroil and all manner of vice grips but it wouldn't budge, so I pushed it over to the welding room to weld a not on. The nut stuck, but it just sheared the bolt off further down, flush with the head.

Everyone was telling me to get a Jim's Tool. Unfortunately, I am poor. I am also 75% of the way through a PhD in mechanical engineering at MIT, so I also have access to a *lot* of nice tools. I measured up my exhaust flange, laser cut a few test pieces to get the fit right, then 3D printed a jims tool. To keep the drill from carving it up the plastic part, I also turned three inserts for the plastic tool to guide the drill bit. 1 for a center drill, then for 1/8" and a size F - the tap drill for a 5/16-18.

I wanted to give myself the best shot I could of not fucking up too badly, so I decided to pull the head and drill it on the bench, since I was pretty wobbly laying on my side with the head still on. I got the whole drilled, but along the way wound up with a nasty gouge in the surface around the hole (see the paper diagram I drew while running the idea by a friend). The plan was to turn a steel/copper plug and put it in the drilled hole, then Tig weld around it to fill in the aluminum and get it cleaned up since aluminum won't fuse to either copper or steel in a welding process. Unfortunately, our Tig machine couldn't get hot enough to keep a nice puddle, even with preheating the head. Add ot that, the other two Tig machines I'm allowed to use around here are down for maintenance since it's the end of the semester.

Look away if you're not open minded, because this is where it gets a lil iffy: in order to fill the gouge, I slid the drill bit I used to fill the hole back into the hole itself upside down, because the shank is just the same size as the hole (if not a little smaller). I wrapped the shank in paper, taped it up, slid it in, and potted the gouge with heat resistant JB weld. The drill bit wouldn't stand up quite straight, so I used a rubber glove and a drill to create a nesting force.

That cured well over night. This evening, I was able to slide the drill bit out, grind the JB weld flat, tap the hole, and install the stud.

To my disappointment, I ordered a head gasket for an 883 on accident, so I need to run back to the Harley dealership tomorrow to exchange that and hope they have a 1200 gasket. With a little luck, this time tomorrow I'll be auto tuning the new air/exhaust system.

So I'm grump today because despite paying $35 for one day shipping on Thursday, the studs won't be here until Monday, so no more work can be done today. I just wanted to post the pictures from yesterday because the process was exciting.

Anyway, per the progress updates from yesterday, I pulled out the gauge pins to get an accurate measurement of the distances between the studs. Not pictured was measuring the bore with a telescoping gauge so that the boss feature on the 3d printed part would index correctly.

I CAD'd up the part, did a couple laser cut pieces to check the fit. And started the print. It took a couple of tries to get the 3d print fight because 3d printing is famously low precision, but once I did the fit was really nice.

I turned a little aluminum insert on the lathe to avoid the drill chewing up the plastic and walking really fast. I put it in and hope for the best.

I should have hit it with a center drill first because the drill did walk a little bit into the aluminum body, but it should be close enough that the flange still fits. The studs are 5/16 and the holes in the flange are 0.36, so there's some wiggle room.

Link to yesterday:

https://www.reddit.com/r/sportster/s/7fNrrbZJwM

The journey continues

Everyone is telling me to get a Jim's tool. Well, I'm poor and I don't trust the cheap ones on Amazon. Dad used to say "you can be poor or you can be stupid, but you can't be both" so it's time to get crafty.

Update I mic'd the exhaust port with a bore gauge and it came out to 1.905".

I'm going to CAD up and 3d print a Jim's tool, and press a little insert for the drill guide. If anyone happens to know the center-to-center distance on the mounting studs, let me know. I'm going to see if I can get measure them reasonabl

Update: I dropped gauge pins in the mounting flange and got some pretty consistent measurements that way. I'm going to laser cut a test piece to see if the features align well enough

Update: with a little adjustment, the test piece fits. Now to 3d print the guide

Update: it took 3 tries to narrow in the gd&t but the fit is perfect you guys. I think I have a real shot at this.

Update: the whole is drilled! It walked a little bit into the aluminum away from the steel which I guess I should have expected but it should be close enough that I can tap and reinstall tomorrow

If I actually weld a nut to this thing and hit the head with a torch, with this stud actually come out? How are they anchored in there

Update I'm going to hit it with penetrating oil for an hour, weld a nut on and see what happens. I'll report back later.

Update someone said try a stud extractor and I've only ever seen the drill and punch kind so I guess I'm going to head to autozone and pick up this cool little collet looking gizmo

Update my propane torch is not hot enough to get this thing to glow I need to go find an acetylene torch or something

Update the stud extractor sucks (not enough material there for solid grip) and I could not find an acetylene torch. Yk what's a lot like a a torch but not quite? Tig welder.

I've sufficiently rounded this sucker over with vice grips and the stud extractor. I'm pulling the battery and pushing this thing over to the welding room.

Update: Welded the nut on. Sheared the bolt off. To those of you who said do it while its hot, that was stupid advice.

Update: I'm going home. The bike will live in the welding room tonight, and I'll trailer it home over the weekend. I'm ordering a screw extractor kit on Amazon because the ones in the shop here are beat to hell.