1974 CB360 Engine Troubles (I think)

rsjudka

Active Member
Hey everyone!
I'm not exactly sure how to start, this is my first time posting but I've already read a ton of the posts on here!

I recently purchased a 1974 CB360 for some mechanic (or so he claimed) and for the first 25ish miles it ran without any problems.

Now, I'm having an issue where white/blue smoke is coming out of the right exhaust as well as some oil. It is also occasionally popping while revving the bike.

I think the bike also is only running on one cylinder (when I unplug the left spark boot the bike dies, but runs the same when I unplug the right spark boot). I tested both coils and they seem to be working properly.

Finally, there is also a weird ticking noise that sounds like it's coming from the top of the engine.

I've done some basic maintanance to it (changed throttle cable, changed oil, replaced a cracked top triple tree) but haven't messed with the engine much.

I feel like these issues could all be related, but I'm extremely new to motorcycles so I'm not sure.

Could someone point me in the right direction to get started? Also, if you think this is more serious of an issue, should I just take the bike to a shop? I would rather much work on it myself.

EDIT: Also forgot to mention, when I ride the bike, for the first 5 minutes or so it feels as if the bike is half powered, can't get over 30 mph. Bike has a very deep growl noise. Then, all of the sudden, the bike rides fine, great power. Sounds like it should (aside from the ticking).

Cheers,
Robert
 
rsjudka said:
Could someone point me in the right direction to get started?


Start here...
http://www.dotheton.com/downloads/CB360T.pdf

Check for proper oil level, Cam chain adjustment (engine at operating temperature), Valve adjustment (engine cold), Points gap / Timing check and adjustment (Stroboscopic timing light - engine at operating temp), Carb sync check and adj - Air/fuel mix adjustment (on center stand, engine at operating temp).

In that order. :)
 
rsjudka said:
Hey everyone!
I'm not exactly sure how to start, this is my first time posting but I've already read a ton of the posts on here!

I recently purchased a 1974 CB360 for some mechanic (or so he claimed) and for the first 25ish miles it ran without any problems.

Now, I'm having an issue where white/blue smoke is coming out of the right exhaust as well as some oil. It is also occasionally popping while revving the bike.

I think the bike also is only running on one cylinder (when I unplug the left spark boot the bike dies, but runs the same when I unplug the right spark boot). I tested both coils and they seem to be working properly.

Finally, there is also a weird ticking noise that sounds like it's coming from the top of the engine.

I've done some basic maintanance to it (changed throttle cable, changed oil, replaced a cracked top triple tree) but haven't messed with the engine much.

I feel like these issues could all be related, but I'm extremely new to motorcycles so I'm not sure.

Could someone point me in the right direction to get started? Also, if you think this is more serious of an issue, should I just take the bike to a shop? I would rather much work on it myself.

EDIT: Also forgot to mention, when I ride the bike, for the first 5 minutes or so it feels as if the bike is half powered, can't get over 30 mph. Bike has a very deep growl noise. Then, all of the sudden, the bike rides fine, great power. Sounds like it should (aside from the ticking).

Cheers,
Robert

Engine is f*cked most likely but small possibility it's electrical. The spark plug "boot" is a separate slip-on piece. There is a brass spike in the boot that pierces into the center of the spark plug wire. Pull the boot off, cut off 1/2-inch of plug wire, and reinstall.

On the engine stuff- put on a pair of Mechanix gloves. Start bike. Immediately touch headers a few inches from head. Both should be getting warm. Go for 5minute ride. Check headers. Both should be HOT. Most likely right will be dead cold. Try above spark plug fix. Re-test.
 
Agreed with both of the last 2 posts. The carbs on the 360 can be very finicky especially if the intake or exhaust has been modified (pods, open exhaust), and the slightest bit off sync can cause running on one cylinder.

It's good practice to do as red said and make sure you're getting a good bite on the spark plug wires.

I would start there, making sure you have spark on both sides: pull plugs out and turn the engine over with the spark plug in the holder and the threaded part touching the engine - you should see a nice blue spark on each side. If not, test your coil on the suspect side.

Once you can confirm spark, 100% go through and do the manual maintenance procedure trek recommended. Follow it to a T. If you are worried about it at all, there is a great set of videos on YouTube by Common Motor Collective that go through all of the procedures in the manual step by step for the Honda twins. They were very helpful for me my first time around.

The ticking is most likely loose valve tappers and will be adjusted in the maintenance procedure. The bike 'warming up and running fine' sounds like carb sync to me.


Sent from my iPhone using DO THE TON
 
rsjudka said:
EDIT: Also forgot to mention, when I ride the bike, for the first 5 minutes or so it feels as if the bike is half powered, can't get over 30 mph. Bike has a very deep growl noise. Then, all of the sudden, the bike rides fine, great power. Sounds like it should (aside from the ticking).

This sounds like the points shorting out. Do you have the gasket under the points cover? I paint the inside of my points covers with the liquid tape.
 
redwillissuperman said:
Engine is f*cked most likely but small possibility it's electrical. The spark plug "boot" is a separate slip-on piece. There is a brass spike in the boot that pierces into the center of the spark plug wire. Pull the boot off, cut off 1/2-inch of plug wire, and reinstall.
So if its not an electrical problem, is it not possible to fix the engine? Or would it just require some extra work?

redwillissuperman said:
On the engine stuff- put on a pair of Mechanix gloves. Start bike. Immediately touch headers a few inches from head. Both should be getting warm. Go for 5minute ride. Check headers. Both should be HOT. Most likely right will be dead cold. Try above spark plug fix. Re-test.
I have checked the engine heat. On startup the left side warms up but the right side is cold. After a 5 minute ride, the left side is burning hot and the right side is only warm. Would it being warm be different than being dead cold?

Thanks for the tip on the spark plug fix, I will definitely try that out when I have the time!
 
advCo said:
I would start there, making sure you have spark on both sides: pull plugs out and turn the engine over with the spark plug in the holder and the threaded part touching the engine - you should see a nice blue spark on each side. If not, test your coil on the suspect side.
I've tested for spark on both sides and I do see a blue spark. However, I'm not sure how big the spark should be.

I have also tested the coils just to see if that could be the issue, and they both spark (as for how big the spark is supposed to be, I'm not sure).
 
irk miller said:
This sounds like the points shorting out. Do you have the gasket under the points cover? I paint the inside of my points covers with the liquid tape.
I do have a gasket I plan on installing under the points cover. I have noticed some oil leaking through the points and am waiting for the seal and rubber plugs to come in some I can try to stop that leak.

Should I invest in some new points or first wait to stop the leaking, then see if the issue continues?

Also, if I need to replace the points, should I replace the coils too?
 
Jesus! Just do what I said to do. then we can go from there. ::)

Dont go blowing your money on parts you may not need. Spend it on the tools you need to find which parts you need.

sync gauges...
http://www.ebay.com/itm/2FastMoto-2-Carburetor-Synchronizer-Carb-Vacuum-Gauge-Sync-Tool-Honda-/201802347691?hash=item2efc5b74ab:g:rYkAAOSwNnRYkQV6&vxp=mtr

Gauge adapters should be bought from crazypj right here on DTT (probably cheapest)
or...
http://www.common-motor.com/honda-360-carb-ports

timing light
https://www.harborfreight.com/timing-light-with-advance-40963.html
 
Here we go, let the attitude begin. Good luck, my man. I hope you get it sorted. Maybe when we're allowed to, we'll talk about how to diagnose certain symptoms. But for now, listen to mom.
 
Some other quick things to try:

While the engine is running, squirt carb cleaner into right carb throat. If the right cylinder fires, you have a fueling issue.

These aren't "fixes" but it's an easy way to pinpoint your problem areas.
 
irk miller said:
Here we go, let the attitude begin. Good luck, my man. I hope you get it sorted. Maybe when we're allowed to, we'll talk about how to diagnose certain symptoms. But for now, listen to mom.

Haha I knew I would catch hell when I wrote that. ;)
Its just the guy is talking about buying coils...When hes got blue smoke and oil out of the right cylinder and a ticking sound from top of engine.

Which reminds me...first thing is a compression test. I believe I have read guys post. They have rented compression gauge from Autozone etc.
Or buy a compression test gauge.
So do a compression test. Your valves may be out of adjustment. (ticking sound) If a seal or guide is worn this can cause oil to enter cylinder. OR it may need fresh piston rings and bore work OR you may have a bent or cracked valve.

Test compression, Adjust cam chain tension. Then check valve clearances. etc

Once youve solved the blue smoke and oil problem. Then start looking at the rest of your list.
 
Thanks guys for the all the advice so far! I'm going to order all the tools to do the regular maintenance first, and then see whats next.

And sorry guys about all the questions, I've just been reading up so much online about people with similar issues and thought I was heading in the right direction (for example, replacing the coils :-[)

Just out of curiosity, because I may have done this a few times, how bad is it to run the engine on the side stand?
 
As long as the oil is kept at proper level and the bike is sitting on level-ish ground its not an issue, to idle on side stand for a little bit. But for maintenance stuff it should be done on center stand. Honda had a bulletin come out in 1976 that recommended changing the oil pickup to a better later design. (CJ360 oil pickup) To prevent it drawing air when idling on side stand. If it does draw enough air to run head dry, the head and camshaft will be toast. Seems it can happen pretty quickly. I have the later, improved CJ360 pickup installed in mine. And I still avoid letting it idle on sidestand.

Also, the early 360s (yours 1974) had a cam chain guide recall. If the guide was replaced by dealer your engine # on the case will have punch mark on it.

Yep, make sure the engine is runnable first. Then concentrate on getting it running.

Like I posted before Autozone may be able to loan you the compression gauge. If you find compression is low. Say, 140 or less add a teaspoon of oil in the sparkplug hole and try it again. If compression tests higher, this shows worn rings/cylinder. If compression remains the same you may have a leaking valve.
 
Yeah I read about the cam chain guide recall, thankfully my bike has that punch ;D

Thanks for the tip about the compression test.

I won't have any time this week to work on the bike (starting an internship :) ), but as soon as the weekend comes I'll get on it 8)
 
The best way to do a compression test on 360 w CV carbs is pulling the carbs off.

Im sure youve read plenty about the top end oiling issues. You could also pick up a tube of 3-bond. You will need it to re-seal the head cover, when you change out the leaky cam shaft seal behind the points and advancer. Since you have that seal you could dig into that and take a peek at your cam and tappet surfaces to ensure its not eaten up by running dry.
When you install the oil seal be sure to lube it up pretty good. If rubber oil seals are installed dry. The friction caused by the rotating parts will instantly burn the sealing edges and it will leak again.
DTT member, "Sonreir" sells the 3 bond at sparckmoto.com

The workshop manual explains how to remove and re-install the head cover in good detail.

Keep us up to date w some pics.
good luck.
 
Sorry everyone I've been really busy with finals and work and life and haven't really been able to work on the bike until today.

I was able to do the compression test, and sadly my bike is at 70 psi on both right and left cylinders :( After adding the oil the readings go up to 85~90psi on both sides. Is this a big enough of a change to show worn rings/cylinders? How low is too low of a reading?

Also, not sure if this affects anything, but I bought the bike with aftermarket mufflers, they look like 16" shorties. Would this affect the compression test?
 
No shorties wont affect readings. Did you have the carbs off the engine? If not pull them off and re-test.
Then go through and adjust valves. Honda manual will tell you how to adj valves. Valves will be the only adjustment you make w a cold engine.
Then re-test. And report back.
 
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