Helicoiling a plug thread in-situ

[fatboyzed]

I dont know about heads on bikes, but i coat the drill and tap in grease, it catches the swarf.
once this is done a drop of retaining compound on the outside of the helicoil and wind it in, let it set THEN break the little bit off, and run the correct tap through to suit the one on your plug.
Be warned tho helicoils dont like it much if you constantly remove and refit.
You can buy solid helicoils or recoils IE they are like a thin pipe with a thread on the outside and inside.
the other option is to buy a two pot mix of liquid metal smear it on the plug push it in and wait a week THEN FLICK IT FAST.

[Flip]

Artery clamp:

The local model shop might have them.

A helicoil is a permanent repair, they are a hell of a lot stronger than the aluminum alloy the head is made of and they have a larger surface than the original thread had to screw into.

I have never heard of anybody loctiting helicoils in, you would be just as likely to glue the coil onto the plug and take it out next time you unscrew the plug, its the spring in the coil that keeps it in place. It's also good shop practice to apply anti-seize to plugs before they are screwed in, it stops these problems occurring.

[Slavvy]

Well, I've succeeded. I cut a narrow strip of rag about 8x50mm and stuffed it down into the bore with the cylinder at TDC. Then I cut the bent handle bit off the helicoil tool and got a mate to weld a rod onto the end of it, then weld the handle onto the end of the rod so the tool was about 30cm long. Wound the helicoil in, then snapped the tang off by twisting with a flathead screwdriver. Used grease on the screwdriver to retrieve the tang.

I cut a long piece of metal coat-hanger, bent the end into a hook and sharpened it with my dremel tool. That let me fish the rag out. Plug now winds in and seals!

Thanks a lot everyone, I definitely learned something here and your tips were very helpful. In the end I didn't loctite the helicoil but I put coppergrease on the plug, I'm banking on this making the plug come out easier than the coil, thus preventing it from winding out when I take that plug out.

[schrodingers cat]

Won't take the heat. In fact loctite theoreticaly won't either, but I've pulled a helicoil out of a head before and it had loctite still OK on the upper turns.

Theoretically correct. The heat softens the loctite but when it cools it resets. Where you get into trouble with a helicoiled (loctite'd) plug thread is pulling the plug with the head warm/hot.

Of course too lieral a dosing can sometimes lock the plug in... Nickel paste or grease or copperslip on the plug thread fixes that.

PS - Also theoretically, best to use nickle paste between steel and aluminium. Copper in a alloy steel sandwich promotes electrolysis. In reality it doesn't REALLY matter

[Slavvy]

Irrespective I've gotten it running, took it around the block just a little while ago and ran great. Thanks everyone!

[Drew]

Glad it worked out man.

[nzmikey]

had to do the same on my 96 Hornet 250 , but we took the head off , 2hrs from putting it in the garage& the bike was stripped , took the head to cycle spot the next day & got it back ($80 to put the heli in ) then spent sunday putting it back together , started at 10 & was riding by 2.30pm

[Drew]

had to do the same on my 96 Hornet 250 , but we took the head off , 2hrs from putting it in the garage& the bike was stripped , took the head to cycle spot the next day & got it back ($80 to put the heli in ) then spent sunday putting it back together , started at 10 & was riding by 2.30pm

Six and a half hours to remove and refit a head?

Bloody Honda poofs!

[nzmikey]

Six and a half hours to remove and refit a head?

Bloody Honda poofs!

ok ok so there was some fucking around & piss drinking .

[Drew]

ok ok so there was some fucking around & piss drinking .

As befits any DIY spannering, ya should have drunk the booze while you worked, and still not had time for two dudes to get through a box of Heineken. (Oh yeah, honda boys. I meant a box of vodka cruisers).

[nzmikey]

As befits any DIY spannering, ya should have drunk the booze while you worked, and still not had time for two dudes to get through a box of Heineken. (Oh yeah, honda boys. I meant a box of vodka cruisers).

Vodka Cruisers ........ it was raspberry daiquiris thank ya very much but yes there was enough consumed to make the job a lil slower than normal .

& I am sure i have heard about you from a couple of my friends , were you not the person who had an a lil while ago . ( doing mono's in Shorts & Jandals ? )

[scumdog]

As befits any DIY spannering, ya should have drunk the booze while you worked, and still not had time for two dudes to get through a box of Heineken. (Oh yeah, honda boys. I meant a box of vodka cruisers).

Fizzy beer type en-garage type drinks are a no-no.

Too much burping and farting...

Spirits are the way to go....