- Joined
- Nov 20, 2008
- Messages
- 1,362
OK so it’s a long way from the Yellow Peril. After I bought my 1st Norton in 72 the 1st Norton owner I met had a heavily Norvilized yellow cafe. I always loved his bike and so when I saw this for sale locally it reminded me of my buddy way back and I had to have it. I’ve owned it for 2 years and finally got some time to try to get it running.
Appearently this bike had been running since being rebuilt but had a bad wet sumping problem. I was hoping to rebuild the oil pump or replace the conical seal in the tc and maybe fire it up but I discovered a pile of other problems now that I have the time to really look more closely. When I 1st saw the bike I remembered feeling some looseness in the header pipe bolts but they were nice and tight the 2nd time I saw it and took it home. After finding the swingarm bushes and rubber mounts are fried I decided to check the threads in the exhaust ports. They are real bad. Then I discovered the left side header had a lot of oil in it and there was a small pool at the mouth of the port.
I’m thinking worn guide, bad seal or a prob with an oil ring on that side. Peering in the spark plug holes you could see freshly honed cylinder walls and fresh valves. I took the rocker covers off to have a look, all 4 adjusters looked like this:
I’m thinking wrong valves or push rods. A compression check showed 120 on both sides but the motor/tranny was moving so badly in the loose isolastics I didn’t try putting oil in and re checking and I was happy with 120lbs anyway. A leak down test showed 25% leakage on the left side and mostly fom the ex. valve. There was nothing noticable from the crankcase. So I pull the head and the 1st thing I see is this:
tiny little ball bearing parked in the valve cut out on top of the piston, WTF? It’s .095” I checked my compression and leakdown testers but they don’t seem to be missing a check ball? The 40 over pistons are nice and snug in the bores. You can see the misty oil deposite on the piston top and where I wiped my finger around the perimeter. There is no patern on the cylinder wall from a gibled oil ring so I’m trying not to take the jugs off. I poured gas in all intake and exhaust ports and the valves are nice and tight with practically zero seepage. Now I think that ball bearing got caught in the exhaust valve when I did the leakdown test and that's why I had the 25% leakage reading. The bright side is it’s got new: pistons, valves, and guides.
Appearently this bike had been running since being rebuilt but had a bad wet sumping problem. I was hoping to rebuild the oil pump or replace the conical seal in the tc and maybe fire it up but I discovered a pile of other problems now that I have the time to really look more closely. When I 1st saw the bike I remembered feeling some looseness in the header pipe bolts but they were nice and tight the 2nd time I saw it and took it home. After finding the swingarm bushes and rubber mounts are fried I decided to check the threads in the exhaust ports. They are real bad. Then I discovered the left side header had a lot of oil in it and there was a small pool at the mouth of the port.
I’m thinking worn guide, bad seal or a prob with an oil ring on that side. Peering in the spark plug holes you could see freshly honed cylinder walls and fresh valves. I took the rocker covers off to have a look, all 4 adjusters looked like this:
I’m thinking wrong valves or push rods. A compression check showed 120 on both sides but the motor/tranny was moving so badly in the loose isolastics I didn’t try putting oil in and re checking and I was happy with 120lbs anyway. A leak down test showed 25% leakage on the left side and mostly fom the ex. valve. There was nothing noticable from the crankcase. So I pull the head and the 1st thing I see is this:
tiny little ball bearing parked in the valve cut out on top of the piston, WTF? It’s .095” I checked my compression and leakdown testers but they don’t seem to be missing a check ball? The 40 over pistons are nice and snug in the bores. You can see the misty oil deposite on the piston top and where I wiped my finger around the perimeter. There is no patern on the cylinder wall from a gibled oil ring so I’m trying not to take the jugs off. I poured gas in all intake and exhaust ports and the valves are nice and tight with practically zero seepage. Now I think that ball bearing got caught in the exhaust valve when I did the leakdown test and that's why I had the 25% leakage reading. The bright side is it’s got new: pistons, valves, and guides.