Honda Twins banner

1 - 3 of 3 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Hi everyone -- thanks in advance for the advice.

I have a 1974 CB360 that I bought a couple years ago. It wasn't running at the time but I restored it and got it running pretty well for a few summers but then the right cylinder started cutting out when I gave it throttle. I couldn't figure it out so I brought it to a shop and the mechanic found a tear in the carb diaphragm. (It has the original carbs). He replaced both diaphragms, and also replaced the points because he noticed they were old.

The original problem with the right cylinder seems to be fixed, but a new one popped up. It’s taking throttle now, but in general is running pretty rough.
When I’m going along at a consistent speed it does ok, but then when I try to give it a little gas both cylinders sputter/ bog so bad that it actually loses speed. If I then open the throttle all the way the misfiring stops and the rpm’s climb and the bike accelerates. It still runs kind of rough but it will at least snap out of the sputtering thing with the additional throttle.
It also sputters when I’m accelerating slowly/ moderately. If I start out from a stop (or the lower end of any gear really) and give it consistent throttle the rpm’s will climb until 4 thousand or so and then it’ll start sputtering and I’ll have to give it full gas.
It seems to get worse as the engine heats up.
Lastly, sometimes when I put in the clutch and coast the bike just dies. I heard that that can happen when the engine gets hot (and has happened to me in the past) so I’m not sure if it’s related, but I figured I’d include it just in case.

Some things to note: the carbs are not professionally synced but it was running fine last year and nothing in the carbs has changed except for the diaphragms. Just to double check though, I cleaned all the jets to make sure that they're not clogged. I also don't think it's the coils because I swapped them out with an old one I had and nothing changed.

Any ideas on what this might be? Could the new diaphragms be bad? Or could it be timing-related, with the new points? Or maybe even the advancer?

Thanks for your help!
 

·
Registered
Joined
·
13 Posts
Well, I've been struggling with a similar problem with my 71 CL350. If you've been into the carbs, you should probably check adjustments again. Set idle down around 1200, adjust mixture to get peak rpm on each, synchronize carbs so the slightest movement of throttle moves both throttles, adjust idle speed so the exhaust feels the same on each cylinder, then reset idle speed by turning each speed screw the same amount. I hope this helps. I did have to check and reset my floats to spec, according to my carb model as they differ from one type to another. In my case the floats were too high, causing a rich mixture. If i shut fuel valve while riding the engine recovered and ran well until the bowls went dry. If shutting off fuel has no effect, the level is probably already too low.
 

·
Registered
Joined
·
13 Posts
There is good info in the first entry in this group by longdistancerider, titled carb info for 350's and 360's. Page 3 has some of my complaints.
 
1 - 3 of 3 Posts
Top