CB360 - Lean Idle

I have a ’76 CB360T. Yes, it has the shit pod filters, but I made a good baffle for the stock muffler so it has good back pressure. It runs great after some fiddling. The timing should be good (but I’m going to triple check) and it runs strong.

My problem is at cold idle it has a very lean condition, idle floats and it sneezes. But once it’s warm it stops and doesn’t happen until I crank it up the next day.

I don’t believe I have a intake leak, I've checked. Yes, I know it’s possible I have a tiny crack, or something that seals itself after heat expands, but I don’t think so.

A/F mixture is good, after some playing it’ll pull to redline and feels good. The original mixture caused it to fall on it’s face around 5,000 rpm. Unsure of the current jet sizes, as again, it’s running good so no need (and I don't remember from when I rebuilt them last). I’d normally leave well enough alone, but I’d like to get this thing as perfect... as possible.

I was going to go up on the slow jet, sound like the place to start? Just wanted to see what others thought.

Have you considered sending them to PJ to mod for the pods? He's got some special mods that light these carbs up and will gain you hp and top end. I was pushing 110 mph on my 75 with just his mods and a hd clutch.

It's definitely your pods causing the issue at idle. I'd start with richening up the idle jet. Or, send them to PJ. It's money well spent, and not much money at all, really.

Sounds completely normal to me, leave the choke half closed till the bike warms up. Some bikes just want some choke and little more throttle when they are cold to be happy. I leave my chokes on about half till I'm out of town usually, I have about a mile of 25-35 mph before I even hit a highway. After that they run perfectly fine. They will sure as shit let me know when they want it open too.

We are all so used to having fuel injected or electronic carbureted engines that do mixture/choke for us that we forget that at one time most gas engines vehicles had manual chokes, you had to actually use them when engines were cold for a little while to keep the thing happy. I grew up with one such farm truck that had to have full choke to start and had to have half choke for around 10 minutes before it was happy.

frogman said:

We are all so used to having fuel injected or electronic carbureted engines that do mixture/choke for us that we forget that at one time most gas engines vehicles had manual chokes, you had to actually use them when engines were cold for a little while to keep the thing happy. I grew up with one such farm truck that had to have full choke to start and had to have half choke for around 10 minutes before it was happy.

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So true. I have a 79 Chevy C10 that I haven't put the choke back on. It runs very well once it warms up. If you try to drive off within a minute or two of starting, it likes to bog or even stall.

I still think you should consider PJ's mod. Hahaha It's the best thing for these bikes that isn't stamped Mikuni.