Modern Vespa

I've bought a mirror for the ET3 and am having a bit of a challenge getting the bolts into the headset. I think the threads are starting to go and in my enthusiasm to get the bolts in have added to this. Basically i got the start of the bolt to bite and then felt the thread go, so its a bit of a cross threaded mess now.


Can anyone confirm the thread size, are they M8x1.0?

I'm not sure, but if it only went a little way in before stripping it can probably be saved by very patiently running the (correct sized) bolt in without the mirror just to re-tap/form the threads.

You can also tap and run a slightly bigger bolt or a helicoil. But once the metal is gone there's no going back so I'd start with the smallest and gentlest repairs first

Thanks,

I'll try again with more patience next time. There does seem to be quite a depth that's not stripped so it might be a case of removing some of the cross threaded bit and then gently trying to get a bolt to bite without too much force.

Take it to someone and have the threads cleaned up with a tap.

taps are cheap if you want to try to clean it up yourself, but it's critical to use the right one

Yeah, and thats the point that I'm at now. Knowing the size is critical. Measuring the bolts that came with the mirror, they are M8 1.25 and this is the same as the bolts that hold the seat down on the PK so i'm expecting that's what the headset is.

I've now discovered that my cheap ebay tap and die set has useless taps in it so will look to get a semi-decent set.

Once ive done that i'll have a bit of a practice before I try again on the headset.

practice on some nuts, especially if you've got some crusties sitting in the corner...

I had the same problem 1 week ago, messed bolt threads and so... tried not to panic and used a M8 tap to clean it, new M8 bolt and done.

I only used taps on college 40 years ago ... even so I didn't scare and did it

Ps: Got it from Amazon a couple of years ago, good quality:
https://www.amazon.de/gp/product/B0058CPERY/ref=ppx_yo_dt_b_asin_image_o02_s00?ie=UTF8&psc=1

I was going to, I've also got the frame for the PK100 sat here which has the same size captive nuts to hold the saddle on, they're full of rust and paint so should be good for practicing on.