Broken Intake Manifold Cap Screw

Hi guys! I am in the process of restoring my '83 XJ750K now that I am in N. GA vs. FL.
Anyway, I have removed the engine from the bike. In the process of removing everything to get the engine out I broke the two screws holding the #2 intake boot. One is flush and the other sticks out a bit.
I have researched remedies for this and cannot find an acceptable answer.
My question is to know if anyone was successful extracting these broken screws. How was it accomplished. Also, are the screw extremely necessary, can I just use gasket maker as a glue type substance?
Sorry if the questions seem really simple, but I usually have my father with me on endeavors such as this, but having moved away from him he isn't here to help.
Any help would be GREATLY appreciated.

 

I extracted a broken exhaust stud using a #3 tip in an oxy-acetelyne rig with a small flame heating the side of the boss it screwed into. Was able to pull it out with vice grips.

I heated the bosses for intake screws when I pulled them. I found that there is enough heat sink into the head that damaging the bosses (by melting them) wasn't an issue with the small flame.

I expect you could use the same method to extract the protruding one. The one that is broken off flush you'll need to drill and run an extractor into.

 

I would buy or rent a good extractor such as the Snap-On shorty-type with the hex drive end. You'll probably have to center-punch and drill using a cobalt or carbide bit. I would definitely use heat as previously suggested along with copious amounts of Aero Kroil. Let it soak at least overnight, then keep applying the AeroKroil as you heat it. It will boil and probably catch fire if using a flame so stand by with an extinguisher. If the tank hasn't been removed already (I assume it has) do so. A high temp heat gun works well as there is no open flame. At any rate, get the boss area around the broken bolt (after it's been drilled for the Easy Out) smokin' hot....after you've thrown the Easy Out in the freezer overnight. With the boss smokin' after soaking in AeroKroil and a super cold Easy Out, the broken stud *should* come right out. The secret is to not get in a hurry and really get the boss around the stud super warm; warm enough so the AeroKroil is boiling away as you spray it on. Good luck.

 

To answer your other question, Yes the bolts are necessary - the boots hold the carbs to the bike, the carbs wouldn't fall out with one loose boot, but the boots MUST be sealed to the head. If you glue it on, the wear and tear and vibration would eventually break the seal of the glue, and inturn break the vacuum.

 

You have arrived where you do not want to be. Both of those fragments will need to come out.

There's not enough room to do the drilling and extracting on the two inside manifolds.

Whatever you do ... DO NOT make the situation worse by taking a chance that some process "Might" work.

If you can't perform the work ... or, don't have the skill and the tools to remove the two broken-off Cap screw fragments. Take the head off and and bring it to a machine shop.

Get all the discusson you need done, right on here, first ... then, do the right thing.

Good luck.

 

I just wanted to update everyone that I had to drill and re-tap the holes. I was able to drill and retap them myselves which let me purchase a nice tap and die set. Purchasing the tap and die set was a GREAT investment as I have busted off two other nuts that I couldn't extract and had to re-tap.
Thank you all for your help and support. I hope to have my bike out onthe road this weekend (just waiting for the gasket kit to arrive).

Shawn