The Breva is now up to 80,000km so I decided that it was time for a service. And since we are in partial lockdown due to Covid, I had plenty of time. The alternator belt was last replaced seven years ago, so now was the time to learn how to do it. I read everything I could on the Guzzi forums and ordered the belt from Mario at Thunderbikes in Perth.
First job, remove the fuel tank.
Then I put her on the bench and jacked her up so I didn’t have to scramble around on the floor.
Moved the oil cooler out of the way, and removed the alternator cover. A bit cramped getting the top screws out, but took my time.
Before I moved anything, I tested the belt tension with my fingers so I had an idea of where I was heading. I moved the coil out of the way to access the lock nut and screw. This tightens up against the alternator to tension the belt. There’re two bolts holding the alternator in position. One undid easily but the other refused to loosen. The nut at the rear was turning with the bolt. Eventually I inserted a spanner from above the left-hand cylinder onto the nut – there was just enough room and I had to get a workshop light to see what I was doing. This held the nut, and the bolt let go with a loud “crack”. (I would have liked to put some grease or CRC 5.56 on the bolt but access wasn’t possible.)
The alternator didn’t move enough to simply lift the belt off. I rotated the lower pulley crank shaft nut and wedged a screwdriver between the belt and the pulley, and she slipped right off. The belt was in good condition – I have seen photos of them being quite worn and shredding. For info, it was a Gates 4PK725, available everywhere. I replaced it with a Moto Guzzi belt, so we’ll see how it goes. The Gates was slightly smaller in diameter than the Guzzi belt and seemed more substantial.
The new belt slipped on with a turn of the crank shaft nut. Tightened up the belt by turning the tensioner screw and lock nut. I assessed the belt tension as I went – should be able to turn the belt 90 degrees the gurus reckon, and that’s how the original belt was when I tested it. Then tightened up the two alternator bolts, replaced the coil, belt cover and oil cooler – job done.
It took me two hours and I wasn’t hurrying.
It’s handy to have a variety of tools. I was continually changing from Allen keys to inhex ratchets, and so on. This el cheapo Kinchrome ratchet which I found in a “Sale” box was worth its weight in gold. Removal of the cover screw (up at 2 o’clock) would have been tedious without it.