8v/4v same things . personally i wouldn't touch an 8v that didn't have rollers . the cost of fixing it is approx. £1200 IN PARTS .
there have been 3 different versions of followers/cams . the only ones 100% reliable are rollers.
there have been 2 oil pumps .
if the cams/followers go , even an oil flush doesn't get all the bits out. ( first one i ever did , the sump was soooo clean it was suspicious ! )
changing the oil at 3k is always going to help.
are you using 10/60 ?
failure mileages .
Griso 3-5k mls , these bikes are used mainly round town
1200 Sport 4-10 k mls used in and out of town
Stelvio 10 k upwards used mainly out of town
here is MY experience of why they go .
i worked on a stelvio with an oil pressure gauge ....
cold start 80+ psi , test ride 6 miles , back in w/shop 20 psi , fiddle with oil pressure relief valve
cold start 90 psi , test ride back to w/shop 22 psi . NOT GOOD . i expect to see a min of 55-60 psi hot .
.
i go and meet a man in a pub 50 miles away , he tells me a story of BMW 1200lc pre-production with same problem .
H-D had a similar problem
he works for a reputable company that solves problems for manufacturers .
he asks what i do to ease the problem , i tell him , he agrees that what i do helps , but will never solve it.
oil takes 20 seconds to get from sump to rocker arms , i checked this for myself.
condensation, i don't think is a factor , oil temperature IS .
look at early and late stelvio's , oil cooler size went up 50% ......
the problem is going away slowly , but last week i did a Griso with 9k mls on the clock , i measured the clearances with ...a screwdriver .
8v/4v= 8v in total or 4/side
2v = 2 / side