ken-rand said:
My question is I am to go and look at a 1975 MK3 850 (located in Spain) for a friend from the pics it looks very nice indeed, however what should I look for, what things can bite you in the arse and cost mega bucks to fix.
If it's been well looked after, then, hopefully, there shouldn't be any expensive hidden problems that might show up later.
A lot of 850 Mk3 camshafts were not hardened correctly so the lobes wore down quickly but most of those original camshafts will have been replaced by now.
One thing worth checking is if the original gearbox layshaft drive side ball bearing has been replaced with the NJ203E roller bearing (or Hemmings 6203TB special ball bearing) upgrade.
The electric starter sprag clutches are not particularly robust and they can kick over-centre or occasionally break - especially if the overload backfire device is not set correctly, however sprag problems appear to affect some Mk3's more than others.
D rods?
Many Mk3s had what are referred to as "D" conrods, and there is a certain amount of controversy as to whether those D rods had an inherent weakness resulting from the way they were manufactured which caused them to break prematurely, however there are opponents to this who maintain that the D rods are perfectly OK.
If the owner will allow it, you could remove the petrol tank and check the frame spine tube for any signs of collision damage (ripples behind the headstock however a slight bowing of the spine tube is normal) and with the tank off, it would also be a good time to check the underside for any cracks or repairs around the tank front mounting studs.
The oil tank can split at its lower mounting so a worthwhile modification is to have the oil tank reinforced at that point.
