Griso 1100 was launched in 2005 but deliveries only really started in 2006. The model was produced for two years really, 2006 and '07 a few were sold in 2008 but were simply plated as that year.
The 8V commenced production in 2007 but once again deliveries only started in the next calendar year. Early 8V's were plagued by several problems besides the flat tappet issues. The rear main bearing flange was prone to leaking and the gasket between the sump spacer and the block was prone to blowing out and lowering oil pressure leading to horrible noises but rarely failures.
The big issue though was obviously the flat tappet fiasco. Early engines had chilled cast iron tappets. These were quickly found to be failure prone, more so in some markets than others, and there was a recall for these motors to replace the chilled cast iron tappets with forged steel ones with a DLC, (Diamond like Carbon.) coating on the sliding face. Unfortunately these too proved to be unreliable and although there was at least on further update to the manufacture the system continued to fail. Sometimes they take longer on one engine than another but they will ALL fail, no ifs or buts.
Be aware that if you are thinking of buying a pre-'13 8V or any 1200 Sport 8V even if you check with a dealer or Piaggio and are told that there are no outstanding recalls on the bike you are looking at it will not mean that the bike has been rollerised as there was never a 'Recall' for rollerisation. In 2012/13 the Piaggio 'Service MotoGuzzi' portal announced a 'Technical Update' which stated that in the event of failure, providing the bike had a full service history and entirely at Piaggio's discretion they would provide a kit for rollerisation but the owner would have to pay for the install. Yes, it sucks, but that's the way it is.
The reality is that these bikes are now seven years old at the youngest. Few have a full history and Piaggio just wants to wash its hands of the situation. A free kit is unlikely unless you have a dealer willing to go into bat for you.
While rollerisation usually fixes the issue on rare occasions the bottom end will fail after rollerisation due to bearing contamination by DLC debris. As I say, rare, but of the couple of hundred rollerisations we've done we have subsequently lost about five motors, one of which was mine.
The answer is to simply purchase a post '12 model as the swap over from flat to roller tappets on all models except the 1200 Sport was in the first half of MY 2012. While there are bargains to be had in buying a flat tappet machine there will always be an element of risk. I've seen engines with sub-10,000km that have completely trashed top ends. I've also seen bikes in their 30's that are only showing the early stages of wear. I'm pretty sure I know why they fail now and it depends on two things, climate and use. The other annoying thing is that until the DLC has all gone and the parent metal of the tappet starts to erode there will likely be no signs anything is wrong. No odd noises or running problems so to the unfamiliar the bike may appear fine. As a general rule if you choose to buy a flattie the lower the mileage on the bike the better!
Checking to see if a bike has been rollerised is very easy. Just take off a rocker cover and look, (There are plenty of pics on the web of what to look for.). If you also want the shop to pull a cambox to inspect the flat tappets? On any model other than a Norge you can pull the left hand cambox in fifteen minutes. If they want to charge you a stupid sum, (One poor sod I know was charged $2,000US for this 'Service' to be told his tappets were fine. They weren't!) tell them to go get a big black dog up themselves!
There are four different rollerisation kits available. They vary greatly in price. That info, and the cheapest way to rollerise, is also widely available on the net. I for one have covered it pretty comprehensively, it's not worth repeating here. If your Google Fu is so bad you can't find it it's probably best you don't look for a flattie!
The other issues associated with all the W5AM Guzzis are them having been 'tuned' by idiots who don't know what they are doing, (There is a thread on this board covering what to do and not to do to the throttlebodies. (That's on a 2V Sport but the principles are the same for an 8V) The other thing is the dreaded grease phobia of Mandello workers. The swingarm bearings and shock linkage are rarely, if ever, packed properly with grease and this should be addressed asap as replacing the swingarm bearings is a right, royal PITA and the shock linkage costs a couple of hundred bucks complete but is within a few dollars of buying the bearings, seals, pins etc. so it isn't worth rebuilding a rooted one.
The long and the short of it is that a well set up and correctly mapped 8V is a magnificent thing. This is not to take anything away from the 1200's, 1100's or 850's with the old 2V motor but in terms of performance there is simply no comparison.
In the same way that diehards here love their V11's I am a CARC bike tragic and 8V evangelist! The loss of this platform I consider an enormous step backwards for Guzzi but judging by the reaction to the V85 I'm in a minority on that score. No skin off my nose but it's a shame that the most advanced engine they built has been shitcanned in favour of an other 2 valve, pushrod, lawnmower engine.