Topic: Mystery threaded insert problem when trying to split the engine case.

[HaaJeHaa]

I'm trying to split my engine cases to fully rebuild my engine. I've removed all of the the bolts, but I've encountered a problem that I can't seem to see the solution to. I've attached a few pictures showing the issue. In the front of the engine theres this "bolt" with a unknow head with no hex/allen/etc, just a small hole. From the underside the "bolt" is M6 threaded. I've tried to to screw it out and drive it out, but its stuck. I've even tried to drill it out, but it seems to be of hardened steel and eats away drill bits.

Theres no mention of this "bolt" or stud in the clymer or owners manual. I've done a few searches and nothing. In photos and youtube videos, this hole seems to be emty?

Any ideas on what this is and how I get it out?

Thanks
-HJ

[pjlogue]

That's a #$%* of a spot to work on it.  My best suggestion is get reverse twist cobalt drills and drill it out.  Cobalt drills will drill through hardened steel. 

Looks like someone mistook a open hole and decided to put a helicoil in it and then ran the 6mm bolt in there where it seized up over time.

-P.

[kmb69]

.....
Theres no mention of this "bolt" or stud in the clymer or owners manual. I've done a few searches and nothing. In photos and youtube videos, this hole seems to be emty?

Any ideas on what this is and how I get it out?

Thanks
-HJ

You are correct. That hole is not suppose to have a bolt in it.

Have you tried drilling the head off from the top?

[Flyin900]

It looks like someone put in a threaded insert from the bottom case, maybe they stripped the case hole originally??? The bolt on top wont turn at all? It looks like some silicone around the base of the head and it also looks really close to the back of the case where I suspect you can't get a socket on it?
Can you get an open end wrench on it to grab the head of the bolt; if so I would heat the area with a propane torch to get it nice and hot and then try to remove the bolt. Maybe a little PB Blaster release agent to cool the hot bolt area as it will pull the agent into the threads as it cools down, just don't have your face over the vapour that is released.

Last resort is a Cobalt drill bit which are a much harder material if you must drill the head off and can be purchased as a single unit in the right size for the job.

[HaaJeHaa]

Thanks guys for fast answers! 

There's no "bolt head", its just a round tip sticking out on top. Hard to measure, but its about 11mm in diameter.  So can't get a socket, or anything really, to grip at that side. Both sides is equally hardened, and my drill bits aren't hard enough.

Guess I must go and purchase a few cobalt drills!

I've now drilled out and tapped nearly every cover screw because the previous guy wrenching on this engine surely did not know anything about how it really is done... The engine even missed a few crancase bolts  I just need to have all the parts inspected and correctly reassembled 

[kmb69]

.....
Guess I must go and purchase a few cobalt drills!
.....

If they are really hard, you need to spin your drill relatively slow and use oil or WD40 for drilling lube.

[flybox1]

dremel the bulk of the head off, or shape the head a bit to better get the drill bit started.

[Medyo Bastos]

Try using a ball buster clicky there ~> https://www.lockmasters.com/ecommerce/CatalogItemDetail.aspx?CID=171&IID=3471


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[madmtnmotors]

Did you remove the transmission shaft carrier bearing and its holder? This bearing holder (under the shifter cover) spans both halves of the crankcase and must be removed.

[PeWe]

Easy to miss a small M6 bolt from the bottom case close to the neautral switch. And one bolt in the starter motor compartment. I have hammered some on the cases when open and a bolt forgotten. More than once :-)
Pure luck that I did not strip the thread.