Hi folks
I could really do with some guiding help here.
I am stripping my Guzzi EV 2004 and when reading the workshop manual (and ChatGPT-40), the advice is to set up TDC rotate the flywheel until the LHS piston is at the top of its stroke and the arrow mark on the flywheel should be in line with the crancase mark.
When I do this the “S” mark on the flywheel is in line with the crankcase mark.
Could someone confirm all is OK with the “S” being in line when the LH piston is at the top of its stroke and why does the reference sources (Manual and Chat) say it should be the arrow in line ?.
The 2 pics show the flywheel in the position with the LH piston at the top of its stroke with the “s” aligned with the red mark on the crankcase.
Many thanks
Remember. It is a 4-stroke. The crank will align with ‘S’ (for sinistro = left; ‘D’ being destro = right) every rotation, but you want the compression = firing stroke. Every other stroke.
I usually ignore the marks, take off the rocker cover(s) and check that both valves are closed at TDC.
Hi Stoneman
Thanks for replying. In fact I do have the rocker cover off and I am checking each time that I am on compression (both valves closed). But what I dont get is the manual and Chat both say to get the timing spot on, the arrow mark on the flywheel needs to align with the crankcase mark, but how can the arrow AND the “S” both align when the piston is at the top of its travel.
Thanks
The arrow is a line on the side of the crankcase to the side of the circular opening, probably has a rubber plug in it about the size of a 2p. The S is engraved on the edge of the flywheel and is visible through the circular opening.
I hope this helps.
Hello Dicky, just reading your concern, if you take anything apart take a picture, but don’t worry these engines are very uncomplicated.
When you remove the flywheel you’ll find the crankshaft is paint marked with the flywheel as with the camshaft, it’s pegged, you can
see the marks on the camchain cogs in your picture. Ps why are you stripping it down it looks pretty good to me. All the best Roy
My bad 
As @Chris950s says, on the bell housing (when the gearbox is in place), the timing mark lines up with the window and crankcase mark.
To be frank I almost always ignore them and just find tdc through the spark plug hole on compression before checking and adjusting valve clearances.
Always followed up with throttle balancing.
Looking at it, have you just done the clutch and main bearing seal? Make sure that the seal is just flush with the casings. Pushed too far in (there is no Beemer-style register to stop it) it can blank off oilways 
Putting the gearbox back on, spend some time with the clutch rod seals and clutch-arm lubing. Always pays off given the rear-wheel crud that gets thrown at it.
Have fun 
Hi Roy
I have suspected a lack of power since I got the bike 5 years ago. I checked the cylinder compression and found it to be 90-110 psi so a little low. My books say should be around 145psi.
So I am taking my time this winter and giving it a thorough overhaul.
Thanks
Hi Stoneman
Thanks for your advice, I will change all the clutch seals as you suggest.
Thanks Chris