need help please,heli-coiled head bolts wont tighten

[redskinman]

Finally figured out today why my head kept coming lose last 3 rides on my 82250r,I kept finding 2 nuts loose on it.Finally realized those 2 cylinder bolts are spinning in place.Took head off and tried to tighten them.I didnt know it but it looks like these have been stripped out and helicoils put on.I have no experience with heli-coils,do these wear out over time? Is there a better way to tighten the studs then with visegrips? I tried 2 nuts together on 1 stud but they kept turning.Can I take them out and put locktite on the helicoils?
thanks

[cbx1170]

heli coils when installed right dont move. no need for loctite either. I have put in hundreds in motorcycle 6,8,10,12,14mm and dozens in aircraft parts 8-32,10-32,1/4-20. get someone to help and carefully remove old one, unspiral it, and install a new in properly prepped holes. helicoil size taps are needed to ck this. clean and dry. there are thread locking style helicoils also. they have 1-2 bent inwards helicoils in center. fastener will not come out on its own. a LITTLE anti-gal lube or moly on bolt threads is OK.

[oscarmayer]

^+1
if that does not work, you may have to look at finding a larger srud and tapping all holes to take next size studs. I may have to do this on my son's racing ATV due to it being a 17-18HP 125cc engine and it has 15.5:1 compression which is causing stock studs to lift. i got litttle stronger ones but who knows how well they will work. if all else. iw ill movce to next sized studs.

[redskinman]

ok guys thanks for advice

[tri again]

Not sure if there;s enough metal but we used actual inserts on aluminum cases,
if that's what they're still called.


They are like short pipes, threaded on the inside and outside and go into the stripped holes.
Those can get 'glued' in and then allow bolts to be reused many times with less worry.

[sblt500r]

i've never had luck with a helicoil holding on a head stud. they don't seem to be able to hold the torque. had time serts hold, but not heli coils.

you can also get steped studs. m10-m8, so you don't have to drill out the head.

[redskinman]

i've never had luck with a helicoil holding on a head stud. they don't seem to be able to hold the torque. had time serts hold, but not heli coils.

you can also get steped studs. m10-m8, so you don't have to drill out the head.

what are "steped studs" and where do I get them?
Upon further inspection of bolt looks like what I thought were helicoils arent helicoils.Since Ive never actually seen in person a bolt that did have helicoils thats what I thought it was.I now think the threads from inside the cylinder have came out with the bolt when I unscrewed it.Never seen this phenomona before either.

[Dirtcrasher]

I've seen it plenty of times.........

A helicoil or threaded insert (depending on wall thickness) will work.

I suggest a mill or other dead nuts vertical boring/drilling etc machine be used.

Stepped studs are thicker/larger on one end and OEM on the other; All you do is tap the cylinder head/base or wherever they originated...........

Wish I could help right now but I'm into other things far to deep.