A good idea, thank you @royston, hadn’t thought about that!
timeserts are better than helicoils from what I’ve read, a bit stronger. never used helicoil myself but have a timesert fitted, they don’t have a snap off but can be finished off with counter sink bit after fitting. i think this reduces the available thread and wouldn’t use a countersink unless i had to. they are a very neat job.
Thanks @sidthedid, I’ll take a look at timeserts
Worth noting that if you do use a helicoil in situ you will have to break the insert tab off with long nose pliers, you cant just punch it off as is normally the case.
Another tip for drilling in situ is to grease the drill bit. Drill a small bit at a time withdraw, clean and reapply grease.
By the way is the thread only partly stripped and could you get by with a slightly longer bolt - I had this on a gearbox level plug. Obviously check clearance with important spinning stuff in the gearbox first
1 Like
Thanks @Mr_P, this is what I was referring to earlier when I mentioned tangless helicoil.
Good advice on greasing to catch the swarf, and yes only appears to be partially stripped so would be interesting to see if a longer bolt would suffice! Will check the spinny stuff, haha!
1 Like
I forgot to mention, my FD repair was a timesert. This followed the reasoning (by the engineering shop) that there wasn’t enough thickness of metal for a helicoil. This might also be the case here.
The machine or tool that installs the timesert folds over the edge on the inside, so that it holds fast. It was a great repair and never leaked. 
2 Likes
I have recently done the one on my Norge gearbox. As stated above use grease on the drill bit and low speed so as not to throw swarf everywhere. I used a timesert insert and used green loctite to seal the insert in. The wall of the gearbox is not very thick and I do not think a helicoil would hold as well.
1 Like
Thanks @Mhirst1211! How did you get straight access to drill? Assume norge access is similiar to stelvio
From memory, strung the rear of the bike up with a chain block from the garage roof. I had to remove the offside footpeg mounting plate and the ‘lamb chop’ plate that holds the gearbox and main stand. Exhaust was also removed. This gave enough room to get a clear run at the drain plug hole. Drilled slowly, tapped to size for the insert and counterbored with the tool in the kit for the insert. I fit the insert using loctite hot strength green to insure it was a good fix and oil tight. Hope this helps.
2 Likes
That’s amazingly helpful, thank you so much @Mhirst1211!!!
Do you recall where you got your time-sert kit supplied from?
We use them at work. The kits are expensive so would ask about at some local engineering works to see if they have one.
1 Like
Also looked at these. They appear to have a slightly oversized thread that will self cut. If you fit it with some loctite it should hold ok.
3 Likes
Hi Adam Where abouts are you? I have a Wurth Timesert kit for M10 x 1.5 that I bought to repair a caliper mount in the front forks of one of my bikes. You could borrow it if it is suitable.
2 Likes
That’s a kind offer thank you @Don-Spada, I’m going to see how it holds for now and hope I can get to winter before I need to sort it properly. I’m based in Bolton.
1 Like
The timeserts made by Wurth that I used where stretched outwards using the mandrel in the kit, and helps to pull the insert into position. The countersinking tool slides over this to recut the sealing face square to the new thread, just incase it is out of square with the original face.
As a tip, don’t put locktite on the full external thread if fitting onto a hot engine - the stuff sets up before the insert is fully home… In the 1970’s a 1" helicoil tap was £100, and you needed 2 of them!
2 Likes
For info.. this is the kit I used to successfully repair the thread after I’d snapped an exhaust bolt flush in the head on my Fazer 600.
Can’t recall what I paid, £35 ish (in 2012).
1 Like
Thanks @KingOrry, that same kit from Wurth now is £193.66!!
Fer Flips Sake.!!
Anyone needing that size let me know 
2 Likes
A pair of needle nosed forcep pliers can easily grab the tang through the large aperture. Just helicoiled both the level and drain plugs on my G5 and got both bits out. However,the aluminium gearbox material on a 1979 Guzzi is a surprisingly hard to rethread for the insert. Hope your later machine is easier.