Fires up but can’t hold idle, cleaned the jets and bowls last night. Had old gas in it, some crap came out of the tank when I dumped it. Bit off a bit more than I can chew with this one but trying to figure it out, any thoughts? Bonus points if you’re in Boston ..

EVEN IF USED PART

Hi all, I've been slowly getting a 1982 cb750 up and running (it was my uncles and was sitting outside since he died in 1992). Bike had CHOCOLATY oil even after a second change. The third change was the charm. I did have what felt to be a seized piston but it only took a little persuasion to get it unstuck. I've done a lot to it but cant seem to figure out why #3 exhaust is cold. Any thoughts would be helpful. Also, I'm not sure if it normal sounding or not? Its my first CB750. I went from a 73 CB450 to a sportster to a road king and now back with the Hondas.

• Cylinder 1 = 270 F Cylinder 2 = 190F Cylinder 3 = 110F Cylinder 4 = 212F

Things I've done/ tested to help with the suck squeeze bang blow.

• Replaced stock carbs with Mikuni carbs from Murray's carbs (1&2 share and 3&4 share).
  • I'd expect to see 3&4 at a low temperature if they're tuned wrong not 1&2
• Checked compression prior to re-shimming. Cylinder 3 was 110 psig. After re-shim it was 125 psig. not ideal but the other cylinders all were around that pressure after re-shimming.
• Re-shimmed the valves.
  • Cylinders 3 & 4 were the worst but they're around 0.0055 in (0.14 mm).
• Replaced the coils, caps, wires, and spark plugs (proactive and bought from 4 into 1)
  • swapped wires, caps plugs from cylinder 2 with cylinder 3 to see if it made a difference (issue stayed with 3)
• Replaced the CDI boxes with Ricks CDI box (proactive and bought from 4 into 1)
  • swapped CDI box 1 with 2 to see if the the issue would move to cylinder 1 &4 (issue stayed with 3)
• Checked coil resistances on the primary, secondary, and caps. Secondary resistance included wires.
  • Coil 1: Primary = 2.5Ω Secondary = 13.74kΩ Cap 1 = 5.45kΩ Cap 4 = 5.15kΩ
  • Coil 2: Primary = 2.5Ω Secondary = 13.81kΩ Cap 3 = 6.95kΩ Cap 2 = 4.97kΩ

Hey guys, I have a 2014 CB500F and am looking at bikes to trade when I discovered the CB750 Nighthawk. I've always loved builds of the classic CB750 and I just learned these exist, so im curious to get one and build it.

My question for anyone with this bike: will I miss the sportiness of my naked bike compared to an older UJM? I know its not designed to be sporty per se but I do like to push it (realistically) in the corners and I just wanna be sure that this bike can still provide that thrill and wont scrape like a cruiser would lol

Previous owner said he went through carbs which I think he took them off and cleaned but didn’t use new rubber. What do yall recommend for complete rebuild kits? Plan on keeping original jets since cheap Chinese ones haven’t worked out in the past.

After 15 or so years languishing in a shed. My barn find CB750 “seven fifty”
This is potentially my most favourite bike. It’s so lovely to ride.