Broken Bolt, Helicoil, options? KC help?

I thought I already had a thread going about this but I can't find it so it must have been my other broken bolt problem (got it out!).

I was putting the finishing touches on a new-to-me NU50... new pipe, belt, DR kit. When I was tightening the head bolts one of them broke. I tried left handed drill bits, easy-outs, etc. When I started I was dumb and didn't remove the engine from the frame and because of this my hole was not in the center. Now that I have the engine on the bench I have drilled out almost all of the bolt (except one side) and I realized that this hole was previously drilled out and I believe a helicoil was used. So now I am not sure what my options are. If I am even able to get the rest of the bolt and the helicoil out, will I be able to use a helicoil kit again? I have never re-tapped (but have a set) and never installed a helicoil. I called a small engine shop and they said they "could try", not leaving me feeling very sure.

I would love to hear your ideas, successes, failures, etc. If someone in Kansas City could help me get this fixed up I got all the free beer and pinball you can stand.

Re: Broken Bolt, Helicoil, options? KC help?

Stephanie Rose /

Possibly , but would have to see a picture to better give you an answer. We had to use a Helicoil and re thread both holes on an express and just stuck bigger studs in and double nutted them and the exhaust is tight with no air leaks. I will have my bf read this thread and see if he can help, he is way more experienced with this issue

Re: Broken Bolt, Helicoil, options? KC help?

pm*d

earl is your savoir

Re: Broken Bolt, Helicoil, options? KC help?

You should be able to pull the hellicoil out like a spring and install another. if the hole is already drille bigger you can try a keensert or keysert, they use a bigger hole for the same size sert, actually come in a variety of wall thicknesses. Another nice thing is they use standard taps.

(edited)

Re: Broken Bolt, Helicoil, options? KC help?

Send pics , good videos. Good luck.

Re: Broken Bolt, Helicoil, options? KC help?

Leo, I got the PM thanks! I will give you a shout later today, your suggestion is much appreciated and knowing someone that can do machinist work locally would be awesome.

Maciek, Thanks for the videos! I came across timeserts (sp?) and keenserts in my google searches but just took them as another brand of helicoil. Now that I see your videos and have watched them both... I believe something more like a keensert was used on my bike. On my lunch break I plan to take a closer look. Judging by the second video you posted I am really hoping they used a keensert as it looks easy to remove without damaging the tapped threads and just insert a new keensert! Sounds like Leo's guy can help me out if I can't figure it out but your videos encouraged me to give it try number 10 before I try a professional.

Re: Broken Bolt, Helicoil, options? KC help?

So I took a look and the insert that was used doesn't appear to be a helicoil or a keensert. It does have two notches directly across from one another at the top (where the keensert video shows 4 notches). Anyone know what type/brand of insert this might be. I hope its as easy to remove as a keensert.

Re: Broken Bolt, Helicoil, options? KC help?

Timeserts are nice when you have limited wall thickness to work with, but the installation taps and tools aren't cheap.

It looks like some of the smaller keysert brand have two notches only, probably come out the same way.

Here's another removal video:

(edited)

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