I have a 2012 Stelvio - built in March 2012 however it is I believe fitted with mk 3 version of the flat tappet system, Larger oil ways feeding cylinder head cam area, higher output oil pump and lower profile camshaft (which produces lower HP 102hp and higher torque ) but still the flat tappet cam follower - Guzzi claim these mods make this later cam system wholly reliable. The mods they have made make a lot of sense and should certainly help the issue if not maybe even completely solve the problem.
Later that month rollers were fitted from i believe engine number 12596, my engine is 12536 so 60 units too early. Rollers are claimed to be used to reduce noise and not a cure for the Mk 3 flat tappet according to Guzzi technical department.
I am unaware of any failures of this latest cam system and can find no evidence anywhere of it failing.
But Guzzi in a way have me locked into main dealer servicing to maintain the warranty on the cam replacement if it does fail.
I have found a way to check the cams followers for failure far in advance of any major damage being done and its not expensive.
It may be of interest to anyone with concerns about this problem.
Millers oils from Yorkshire, (millers oils.co.uk) offer an oil analysis service which can detect abnormal particles of metals in the oil these would show up excessive wear of individual components by the metals they find in the oil at an almost microscopic level. They say they know what would be normal for most engines and can identify metals from camshafts, bearings, followers, pistons and barrels along with a host of other components as individual wear. once analysed the report outlines possible problem areas. If they are unable to id then a comparison test can be carried out after a period of time / mileage and that comparison would show up wear rate differences of particular metals in the oil ie alloy/ steel/ iron/case hardened metals etc.
The single test is £24 and the two part test £39.95.
I have no connection to Millers oils but think this may help put to rest worries for people concerned about premature wear on the Cams/ followers and also identify the failure long in advance of any engine damage being caused. How Moto Guzzi / Piaggio. might react to the test I am not sure but I do think it would give very good grounds for a warranty case in advance of a lot of noise from the engine.
Regards Jake.