1976 Honda CB360T - The first step is admitting I have a problem build
- Thread starter 620dark
- Start date
620dark
You can always get it running with time or money.
Yea, I was all happy walking out of the Autozone with a set of hotter plugs in my pocket and decided to snap that picture.
So here's the thing - I've torn down the motor, and can't find anything wrong. The rings were all back in their proper places on both pistons. What the heck (other than way worn bores) would cause a piston ring to catch and hang up like that?
The only other thing I can think is that I dropped a valve seat, but the valves look fine! So strange.
So here's the thing - I've torn down the motor, and can't find anything wrong. The rings were all back in their proper places on both pistons. What the heck (other than way worn bores) would cause a piston ring to catch and hang up like that?
The only other thing I can think is that I dropped a valve seat, but the valves look fine! So strange.
620dark
You can always get it running with time or money.
I was able to poke the ring with a screwdriver - believe me, I didn't trust my eyes either! The head gasket rings are intact - that was my immediate thought after I saw the rings intact.
The valve springs look intact, but I'll pop the valves out anyway just to see what's going on. I need to measure the bores of the cylinders as well.
The valve springs look intact, but I'll pop the valves out anyway just to see what's going on. I need to measure the bores of the cylinders as well.
mydlyfkryzis
当有疑问时踢你的敌人在生殖器上，你可以道歉后
You aren't using any, err, substances, that might make you, err, see things that aren't there?
No way the ring is out of the groove without the groove having been damaged.
I can't even speculate on what you were seeing, especially if you could manipulate it with a screwdriver..
No way the ring is out of the groove without the groove having been damaged.
I can't even speculate on what you were seeing, especially if you could manipulate it with a screwdriver..
620dark
You can always get it running with time or money.
I was only high on life ;D
All seriousness aside, I had a great ride, and pulled the plugs to examine them. I had to look about half a dozen times to convince myself, and even after I poked it with a screwdriver I still wasn't believing my eyes. I stuck a little USB borescope camera I have in there, and it didn't tell me much more as it couldn't focus that close, but it was what it was. My next step is to measure the bores with my fancy newish bore measuring tool (that I didn't have when I built this motor). Wouldn't it be funny* if the motor was bored out and I put stock sized rings in it?
*funny as in "time to start drinking"
All seriousness aside, I had a great ride, and pulled the plugs to examine them. I had to look about half a dozen times to convince myself, and even after I poked it with a screwdriver I still wasn't believing my eyes. I stuck a little USB borescope camera I have in there, and it didn't tell me much more as it couldn't focus that close, but it was what it was. My next step is to measure the bores with my fancy newish bore measuring tool (that I didn't have when I built this motor). Wouldn't it be funny* if the motor was bored out and I put stock sized rings in it?
*funny as in "time to start drinking"
620dark
You can always get it running with time or money.
Ok, data from measuring and poking today and some fun pictures!
As you can see, there's no obvious damage to the rings or piston:
According to my boreometer (heh), the left bore is 2.6395". The service limit is 2.6417" and the "good" range is 2.6382" - 2.6386". So pretty close to good?
Finally, my ring gap installed is 0.53 mm. The service limit is 0.8 mm, and the "good" range is 0.2 - 0.4 mm. So, close again?
Tomorrow I'll remove the valves from the head and make sure I haven't dropped a valve seat or something goofy like that. This problem really has me, uh, "ringing" my hands. Heh. Heh heh.
As you can see, there's no obvious damage to the rings or piston:
According to my boreometer (heh), the left bore is 2.6395". The service limit is 2.6417" and the "good" range is 2.6382" - 2.6386". So pretty close to good?
Finally, my ring gap installed is 0.53 mm. The service limit is 0.8 mm, and the "good" range is 0.2 - 0.4 mm. So, close again?
Tomorrow I'll remove the valves from the head and make sure I haven't dropped a valve seat or something goofy like that. This problem really has me, uh, "ringing" my hands. Heh. Heh heh.
Buh-dum-Bump or Wha- Whaa-WhaaaaWorst cb650 ever said:
ok i dont know a dang thing about what all is required when installing + .25 rings. Is there any actual machine work required when doing this? Or, simply a good hone and make sure cylinders are still nice and round?
you could order a pair and measure them up.
I mean really. Its only money.
620dark
You can always get it running with time or money.
I already ordered a set of new (to me) jugs, with good used pistons and rings, so I think I'll start there. This is so weird, I can't really explain what I saw. I still need to remove the valves from the head to make sure I didn't do something weird with a valve seat.
I did notice that the pistons have a good amount of play side to side on the wrist pin, but that should be normal, right? There's no detectable play up and down, just left and right on the rod, which allows the piston to center in the bore, right?
So damn weird. My brother and I installed the removed piston and its rings in the removed jug, and it fit snug as it should.
I did notice that the pistons have a good amount of play side to side on the wrist pin, but that should be normal, right? There's no detectable play up and down, just left and right on the rod, which allows the piston to center in the bore, right?
So damn weird. My brother and I installed the removed piston and its rings in the removed jug, and it fit snug as it should.
crazypj
Split personality, I fake being smart
trek97 said:
You file the ends of oversize rings to get the correct (usually minimum) gap in bore.
It's a PITA with 3 piece oil rings because they are so thin.
It can be done with a file but a proper gapping tool makes life a whole lot easier
http://www.cylinderheadsupply.com/4288.html
You can get them for abut $30.00, this is just the first one I found online
Was the problem on left cylinder?
Looks like valve may have scraped the cutaway in piston slightly?
620dark
You can always get it running with time or money.
crazypj said:
Good eye PJ, when the tensioner stopped, uh, tensioning, the previous owner spun the motor over enough to slightly bend one valve and nick the piston with the older valve. I smoothed the nick and replaced the valves - if we journey back to December 25th, 2012 in this thread, you can see the carnage. Note that the valve actually broke as I was removing it - it was not broke in the head:
