- Joined
- Feb 12, 2013
- Messages
- 1,559
My 74 850 is stripped. How do I know if I have the "D" con rods that are supposed to fail if an engine is not put together correctly. I have been sifting through many of the past threads and seen what people have written about them. The general feeling is that they are bad news, but someone mentioned they got a bad name because a sloppy racers engine came to grief because of his sloppy engine work, and the rods got the blame. How true is this?
I have plenty of time because she who ought to be obeyed is going on about the amount of money I have poured into these two Nortons, and I should have bought a more modern bike instead of this 850. Where is the fun in that. I got the blah, blah, blah this morning when I told her it cost me $230.00 to have the lug welded back on the r/h c-case [ top one where it bolts to the g/box cradle ] and 5 new crank case to cradle/iso mounting bolts.
Interesting the amount of slop between the bolts and the holes in the engine. Disgusting actually .
Its funny as well that when I checked the l/h valves, none were bent, but I do need two new exhaust valves. I thought the l/h valves must have got bent as a result of the two l/h con rod nuts working loose, but although there is a minor witness mark from the valves touching the piston, it is more that they have cleaned the carbon off the piston tops. How lucky is that?
The reason for the engine to appear to have leaking valves can probably be put down to carbon holding the l/h exhaust valve open. When I pressure tested before removing the head, air just pissed out the exhaust on the l/h cyl. On the bench, putting petrol into each combustion chamber, and blowing compressed air down the ports indicated the inlet valve were not leaking, but both exhaust vales were. Both ex valves have started to pit so two new ones are going to have to be ordered.
Dereck
I have plenty of time because she who ought to be obeyed is going on about the amount of money I have poured into these two Nortons, and I should have bought a more modern bike instead of this 850. Where is the fun in that. I got the blah, blah, blah this morning when I told her it cost me $230.00 to have the lug welded back on the r/h c-case [ top one where it bolts to the g/box cradle ] and 5 new crank case to cradle/iso mounting bolts.
Interesting the amount of slop between the bolts and the holes in the engine. Disgusting actually .
Its funny as well that when I checked the l/h valves, none were bent, but I do need two new exhaust valves. I thought the l/h valves must have got bent as a result of the two l/h con rod nuts working loose, but although there is a minor witness mark from the valves touching the piston, it is more that they have cleaned the carbon off the piston tops. How lucky is that?
The reason for the engine to appear to have leaking valves can probably be put down to carbon holding the l/h exhaust valve open. When I pressure tested before removing the head, air just pissed out the exhaust on the l/h cyl. On the bench, putting petrol into each combustion chamber, and blowing compressed air down the ports indicated the inlet valve were not leaking, but both exhaust vales were. Both ex valves have started to pit so two new ones are going to have to be ordered.
Dereck
