damonbauer
New Member
I’m having a heck of a time getting my ‘72 CB350 running properly. As of now, it only runs on the LEFT cylinder. Here’s what I’ve done/tried/troubleshot:
- Rebuilt carbs. Set floats with carb in the vertical position, with the float tang just barely resting on the float needle); they are at 25.6 - 26.4 mm
- Checked compression at each cylinder by shoving a paper towel in each, starting and watching the paper towel shoot out (yes, poor man’s test but it’s all I got)
- Check (two different sets) spark plugs have spark by grounding the wire & plug, then starting
- Battery is at 13.11v
- Getting power all the way to the points
- Adjusted the cam chain tensioner
- Gas in the tank, petcock allowing gas to flow to carbs. Bowls are filling.
Now… for where I think the problem is:
- Installed new ignition points
- The points plate was slightly bent, so I pounded it on an anvil as flat as I could
- Points cam advancer seems to operate smoothly
- Timed properly, at least how I understand it. Gapped left point to spec, then rotated plate in order to get test light to fire at LF. Then adjusted right point to get test light to fire at F, 180 degrees after LF.
Finally, I know the right cylinder isn’t firing properly because:
- The left exhaust header is SCREAMING hot, but the right is barely warm (I can keep my hand wrapped around it while the bike is idling)
- While idling, I can independently pull the left throttle cable at the carb only, and the bike revs. When I pull the right throttle cable at the right carb, the bike dies.
- While idling, when I pull the left spark plug wire from the spark plug, the bike dies. When I pull the right spark plug wire from the spark plug, the bike continues idling.
- While idling, I have to keep the throttle slightly open, or the bike dies.
OK… that about covers it.
I’m about 75% confident that I’m setting the timing properly (can I get confirmation here?):
I think I’m on the compression stroke by holding my finger over the spark plug hole, rotating the engine and feeling a bit of air as well as hearing a “pssssst” sound. Once the rotor passes TDC, the rotor jumps and advances really quickly. So I stop at the LF mark and set the point. Then, I rotate 180 degrees to the F mark and set the point.
Could the fact that I had to pound the points plate flat be causing the points to misfire? Am I missing something obvious? Any help appreciated, I’m getting pretty discouraged :/ I’m happy to take pictures or videos if that would help! Thanks!
- Rebuilt carbs. Set floats with carb in the vertical position, with the float tang just barely resting on the float needle); they are at 25.6 - 26.4 mm
- Checked compression at each cylinder by shoving a paper towel in each, starting and watching the paper towel shoot out (yes, poor man’s test but it’s all I got)
- Check (two different sets) spark plugs have spark by grounding the wire & plug, then starting
- Battery is at 13.11v
- Getting power all the way to the points
- Adjusted the cam chain tensioner
- Gas in the tank, petcock allowing gas to flow to carbs. Bowls are filling.
Now… for where I think the problem is:
- Installed new ignition points
- The points plate was slightly bent, so I pounded it on an anvil as flat as I could
- Points cam advancer seems to operate smoothly
- Timed properly, at least how I understand it. Gapped left point to spec, then rotated plate in order to get test light to fire at LF. Then adjusted right point to get test light to fire at F, 180 degrees after LF.
Finally, I know the right cylinder isn’t firing properly because:
- The left exhaust header is SCREAMING hot, but the right is barely warm (I can keep my hand wrapped around it while the bike is idling)
- While idling, I can independently pull the left throttle cable at the carb only, and the bike revs. When I pull the right throttle cable at the right carb, the bike dies.
- While idling, when I pull the left spark plug wire from the spark plug, the bike dies. When I pull the right spark plug wire from the spark plug, the bike continues idling.
- While idling, I have to keep the throttle slightly open, or the bike dies.
OK… that about covers it.
I’m about 75% confident that I’m setting the timing properly (can I get confirmation here?):
I think I’m on the compression stroke by holding my finger over the spark plug hole, rotating the engine and feeling a bit of air as well as hearing a “pssssst” sound. Once the rotor passes TDC, the rotor jumps and advances really quickly. So I stop at the LF mark and set the point. Then, I rotate 180 degrees to the F mark and set the point.
Could the fact that I had to pound the points plate flat be causing the points to misfire? Am I missing something obvious? Any help appreciated, I’m getting pretty discouraged :/ I’m happy to take pictures or videos if that would help! Thanks!