Bought a CB360, was running only on right cylinder. Has spark, compression, fuel in the bowls. I took the carbs off and went through them, replaced some o-rings and gaskets. Left side cylinder would pop, bike would idle around 2000 rpm. Sync’d the carbs by feel using an old string from one of my instruments. Adjusting the carbs at the main screw I could get the left side to run but the right would run rich or flood. Or the right side would run and the left side would starve. This bike is pissing me off and I’m not really sure what I’m dealing with. Need suggestions and tech advice. I know just enough to know how little I know.
Cb360 running on one cylinder
- Thread starter MacGyver
- Start date
These are CV carbs, so you have to sync by either pointing an infrared thermometer at each header and adjusting to get temps to match, or with vacuum through the sync ports on the outside of each carb.
Welcome to DTT.
If you don't already have the Official Honda workshop manual, get one. It can really save the day.
Besides a proper sync, sounds like you need to dial in Air/Fuel mix, on both. (eingine at operating temps, hot)
The left pilot circuit may be clogged.
To get it idling at 2krpm you're actually feeding fuel through the main primary. working around a clogged pilot.
This could cause the right to idle rich, as its feeding through pilot and main primary.
Post pics of your bike. Does it have stock filters/air boxes or pod filters or no filters?
If you don't already have the Official Honda workshop manual, get one. It can really save the day.
Besides a proper sync, sounds like you need to dial in Air/Fuel mix, on both. (eingine at operating temps, hot)
The left pilot circuit may be clogged.
To get it idling at 2krpm you're actually feeding fuel through the main primary. working around a clogged pilot.
This could cause the right to idle rich, as its feeding through pilot and main primary.
Post pics of your bike. Does it have stock filters/air boxes or pod filters or no filters?
Are your carbs factory to the bike? If so the vacuum adapters you ordered may be too small to fit. Stock carbs use 6mm adapters - They can be ordered from crazyPJ on here or from Common motor collective. https://www.common-motor.com/honda-360-tools
What type of filters are installed?
Numbers on the gauge really dont matter to you. They just need to be tuned the same at idle.
And now the entire pilot circuit is clear? Fuel enters at the main primary-feed hole to pilot jet under screw (liquid fuel is then atomized)-feeding atomized fuel to A/F adjustment - then onto the 3 small holes in the bore.
Its the 3 small holes that get easily plugged and can be a bitch to clean as there is a large cavity they are fed through. The cavity can hold a large amount of trash, and can only be accessed w cleaner, compressed air and thin wire entering through the holes. Dont remove the plastic plug to the cavity itself.
An old pic I snapped spraying cleaner through the large A/F mix hole and the 3 small pilot circuit holes...
Set up A/F mix according to manual.
If this is all clear your problem may be a vacuum leak. Check insulators (rubber boots at the head) for cracks or they can easily be permanently warped by over tightening the two screws to the head. I coat the gasket w a little Hondabond.
Add a drop of heavy oil to the felt seals on linkage shafts, ensure the caps are in place to seal the outboard shaft ends.
Links to carb stuff Ive done...
http://www.dotheton.com/forum/index.php?topic=27417.msg885289#msg885289
http://www.dotheton.com/forum/index.php?topic=63133.0
What type of filters are installed?
Numbers on the gauge really dont matter to you. They just need to be tuned the same at idle.
And now the entire pilot circuit is clear? Fuel enters at the main primary-feed hole to pilot jet under screw (liquid fuel is then atomized)-feeding atomized fuel to A/F adjustment - then onto the 3 small holes in the bore.
Its the 3 small holes that get easily plugged and can be a bitch to clean as there is a large cavity they are fed through. The cavity can hold a large amount of trash, and can only be accessed w cleaner, compressed air and thin wire entering through the holes. Dont remove the plastic plug to the cavity itself.
An old pic I snapped spraying cleaner through the large A/F mix hole and the 3 small pilot circuit holes...
Set up A/F mix according to manual.
If this is all clear your problem may be a vacuum leak. Check insulators (rubber boots at the head) for cracks or they can easily be permanently warped by over tightening the two screws to the head. I coat the gasket w a little Hondabond.
Add a drop of heavy oil to the felt seals on linkage shafts, ensure the caps are in place to seal the outboard shaft ends.
Links to carb stuff Ive done...
http://www.dotheton.com/forum/index.php?topic=27417.msg885289#msg885289
http://www.dotheton.com/forum/index.php?topic=63133.0
Doesn't look like it's been mentioned yet, but running on only one cylinder is a classic symptom of a dead or dying battery on the old Honda twins.
Hook up some jumper cables from your car (keep the car turned off) and run the bike again. If you have both cylinders running then it's time for a new battery on the bike.
Hook up some jumper cables from your car (keep the car turned off) and run the bike again. If you have both cylinders running then it's time for a new battery on the bike.
trek97 said:
This could still support what Matt suggests, since it's getting to the point of alternator voltage over battery voltage.
trek97 said:
I attempted to clean them out with a wire already, kind of hard to tell if I got anything done.
Carbs are stock, if they are original, I don’t know.
I’ve got pods on the bike, but they’re mashed up to fit around the battery box, need to move it and replace the pods.
Battery is brand new, not a battery issue.
MacGyver said:
Yea, no shit its hard tell if they are clean.
Cheap pods can have a lip inside that block airflow to circuits. (if I recall correctly)
These carbs are difficult to make run properly w pods of any kind. I had best results w K&N. To stand any real chance w pods the carbs will require mods by crazyPJ,
A new battery doesn't necessarily mean a good battery. Is it charging properly?
also, you installed carb kits?
Are the kit jets same sizes as original jetting?
As long as the original factory jets are usable condition. I highly recommend re-installing them.
just keep the new float valves and seats.
New kit A/F needle springs have sharp edges that can shave brass and aluminum flakes. The original springs are ground smooth on ends.
Are the kit jets same sizes as original jetting?
As long as the original factory jets are usable condition. I highly recommend re-installing them.
just keep the new float valves and seats.
New kit A/F needle springs have sharp edges that can shave brass and aluminum flakes. The original springs are ground smooth on ends.
Sounds like sync to me. They are really sensitive to it and my 360 would come alive when vacuum synced, and often run on 1 cylinder when it was just bench synced.
That being said check the battery and charging like these guys said too.
That being said check the battery and charging like these guys said too.
cb360j
Been Around the Block
When my 360 is low on fuel, like reserve levels, it will only run on the right cylinder at idle, butttt if you rev the piss out of it when riding and low on fuel the second cylinder will somehow get fuel and somehow run. So.. maybe check fuel? It is super finicky that way.
It also really wants to be synced like advco said.
It also really wants to be synced like advco said.
