The owner has bought the big bore kit from Gutsibits, so I presume that will all fit well 
As stated the sump extender is well cheap, but I can’t see how that would help move the screw on filter outside.
Now I’ve heard that that the filter was an ‘add on’ from Guzzi, that explains it. At least they did add some form of filter, which is more than LAverda ever did! Bit like Brit bikes having the gear change on the wrong side - that came from moving from hand change to foot change, but the tight arsed companies didn’t want to spend the money on moving the gear change across to the more logical side. The Japanese started with a clean sheet so obviously started with the change on the left. The Brits only moved when they were losing sales, but it was all too little too late, hence the demise of the British bike industry along with the car industry. Stupid and greedy management profiting from the glory days and not re-investing, combined with an idle work force with overly powerful unions, killed the British motor industry.
You can get a sump extension that moves the oil filter outside of the sump, but that version is not cheap!
That sounds like a great idea I will recommend it to the owner. It’s far more likely to get more filter changes if he doesn’t need to take so much of the bike apart to do it!
It talks about a different dipstick. Doesn’t it just have more oil in it? Presumably the pick up level is unchanged?
No it has the same amount of oil with a sump extension, the pick up is ducted through the extension down to the sum, hence the need for a longer dipstick. The benefits are that the crank does not drag through the oil bath in the sump and the oil is further out in the breeze for cooling.
I have a sump extension on my bike with air ducts cast in from front to back to allow cooling air to pass all sides of the oil in the sump.
Filter does not need changing with every oil change. I can’t remember what the ratio is as I only have a filterless loop-frame Guzzi now. On that one, I drop the sump every second oil change to check the filter screen and clean the sludge out of the sump.
Moto Guzzi may not suggest changing the filter every time you change the oil, but then they thought it was OK to firstly not filter the oil and then when that didn’t work out, to hide the filter inside the engine. I can assure you that you should change the filter EVERY time you change the oil on ANY engine.
My manual says oil filter should be changed every 5 oil changes, and many big-block Guzzis have covered massive mileages on that regime. Presumably the ratio depends on the volume of oil compared to the dirt-holding capacity of the filter. These engines also have centrifugal sludge traps in the crankpin which will deal with a lot of particles in the oil. But I’m not really an expert, as I only have 40 years experience in vehicle design and development!
PS - My loop has done 58,000 miles with no filter but rigorous oil changes at correct intervals. I took the big end caps off last year and they were all good. The biggest problem loops have is when they shed the chrome from the bores and it gets into the bottom end.
Just looked in there…
That’s been in there for 30000km, oil changed every 5000 (fully synthetic 10/60)
I’m not casting any doubt on your career, my apprenticeship was with British Aerospace, but I have always been taught that one changes the filter with the oil and given how inexpensive filters are I can’t see an issue with this. I tend to use HiFlo filters which are at the very least up to OEM spec and often exceed it and to the trade they cost buttons and on the vast majority of bikes are easy to change. If everything is OK then maybe a filter can last longer without being totally compromised, but why add restriction when it is unnecessary. Filters are so cheap and oil and engine wear so expensive.
I look after a Jota for a friend and that has no filtration either; he simply has to change the oil extremely often; It is so often he does it himself. The advice is to change the oil every 1000miles, but never more that 1500. With modern oils and filtration the mileage between oil changes is extended massively. From memory I think my van has an oil change every 40,000miles or every two years. (Vito). Given the cost of decent oil filtering it has much merit IMHO.
+1 this - I have used sump extensions, it turns out the modified max. level corresponds to the min. mark on the stock dipstick. My second bike came with an extension already fitted, plus a homemade or modified dipstick, but unfortunately I found one day the rod had fallen off into the sump, so that was the end of that. So I got a stock dipstick and used the min mark as max., and the end of the rod as min.
The chap who owns the bike has bought a new sump with built in exterior oil filter. I look forward to seeing it 