Cali EV Rear Suspension Mount

Technical Big Block Tonti and Loop Frame models
#1

I am refurbishing a 97 EV and have found the upper suspension mount thread to be worn. Parts List says that it should be M6 * 35, but these do not hold. Either corrosion or previous-owner brute force has opened the holes up. The earlier Cali1100i/EV 8mm screw will not fit and I suspect that the suspension mount is smaller diameter than the earlier frames. (Can anyone confirm?).

Oddly enough, a good-old British Association (OBA) will screw in and hold. I know that OBA is nominally the same as M6, being 1mm thread pitch, but with slightly different thread form and outside diameter. (6mm OD instead of M6’s 5.794mm-5.974mm OD).

I know that the screw does not, in fact, do much other than retain the suspension unit on the mount, but I don’t want to unnecessarily weaken the mount post.

I could (I know) simply tap out to M7 * 1.0, or alternatively I could drill deeper and then re-tap M6 * 1.0 with longer screws.

I would appreciate any suggestions or prior experience.

#2

If that’s true that’s a bit mad reducing it from M8.

#3

I did not explain myself well.

The earlier ‘KD’ frames had 14mm Suspension Mount Posts with M8 screws. The later ones had 12mm posts with 6mm screws.

Don’t ask me why; one of those strange, but true Guzzi Cosmic Mysteries?

Might be to do with Guzzi/Piaggio moving away from Bitubo Air Shox to those nasty Sachs-Boge things. I now have some decent adjustable Hagon Shox as the original Bitubo Units died.

#4

Yes must be because the mounting eye size changed.

#5

Update…

Decision made i.e. drill deeper than the current 21mm and re-tap M6 * 1.0. This will not weaken the mount post and only requires longer screws.

Will update when the frame is back from the paint shop and re-assembled.