Chris (Many thanks to Chris) has suggested the following tip as the studs that hold the barrells onto the crankcase on older bikes tend to corrode and jam into the recesses designed for them.

This is generally caused by years of road salt, combinbed with Galvanic Corrosion (Basically the aluminium corrodes because of contact with the steel).

Chris's tip is a very simple yet effective idea which saves you from thumping the barrells and breaking the fins. You hit the plate shown below in the photo while holding the barrells in your hands and the pressure should force the studs down, releasing the crankcase. Make sense? See below.


Place the nuts (M10 x 1.25mm) on either side of the plate (Drawing below) as above and secure with a 17mm spanner.

Give the plates a good hit to break the seal then be patient as it will take a while to get the barrels through the studs with a punch and WD40.