CB360 running on one cyl...timing moved

[ShortyLaVen]

Hey guy! Im working on my newly acquired '76 CB360 and its now only running on one cylinder. I had an issue of it bogging down under load between 3 and 5k rpm. I checked float height, cleaned and set my points, and set my timing. After firing it up again I found that it only runs on the left cylinder. I took the points cover off (I read the points wires can short out to the cover) and still the same thing. After that I checked my timing again, and the left cylinder is slightly retarded (light comes on just past LF), and the right is very retarded (light doesn't come on until T mark). Im assuming that this could cause the right cylinder to not fire, but what caused the timing to move? All screws are tight.. maybe when I set the timing before the advance was stuck, and now its unstuck? Any help is greatly appreciated.

 

[ShortyLaVen]

Thanks for the replies! I reset my timing (I always turn it counterclockwise like is proper) and reset points, still only running on left cyl. I have not taken the advancer off yet, but when I do I'll be sure to grease everything up good.. I static set the time only because my strobe isn't handy (left it at work). I can see the righthand points firing however so I'm going to move on to the carbs... maybe the diaphragm didn't seal right or something...I'll post back with what I find

 

[ShortyLaVen]

Well... I can't believe I didn't notice this before..... while I was putting everything back togehter I found there is NO SEAM BETWEEN THE HEAD AND CYLINDERS!! whoever worked on the bike last (the previous previous owner) smeared a nice coat of JB Weld around the entire thing!! So that prettt much does it, im going to do a complete tear down. Or at least a top end rebuild.. To quote a famous person in history, "Shit just got real." At least winter is coming!

 

[trek97]

I found there is NO SEAM BETWEEN THE HEAD AND CYLINDERS!! whoever worked on the bike last (the previous previous owner) smeared a nice coat of JB Weld around the entire thing!!

Before we freak out, stop for a minute and take a breath. Post a pic. Because unless your 12 inches tall, a chinese contortionist or using a mirror and a bright light, seeing the head gasket is virtually impossible.

Are you talking about between the head cover and the head? OR the head and cylinders?

The head cover and head dont get a gasket, only a smear of Hondabond. AND its easy to see. And its gray...like JB weld.

The head and cylinders do get a gasket. Its hard to see.

I can see the righthand points firing however so I'm going to move on to the carbs... maybe the diaphragm didn't seal right or something

The diaphragm doesn't have anything to do w the non firing issue. Theoretically, it would start and idle just fine if the diaphragm wasn't even installed in there. Hell, you could probably ride the thing up to 30mph, 3000rpm or so, before noticing an issue.

Pull the left plug out, plug it back into cap, ground it on engine and hit the starter button. To see if you got spark at the plug.

If it dont have a spark at the plug...

A wire came unplugged, or going to ground, or fouled plug or something simple like that.

swap plugs or try a new plug.

double check static time...keep in mind the plug sparks just as the points "open"

Ive always unplugged coils and used my fluke meter to static time. So, not 100% sure how you did it. If you had your key turned on for a length of time its possible she's fried the coil or something?

If you see the plug has a nice bright blue spark...

Crack Open the bowl drain and make sure she's got fuel sitting in the carb. Maybe float needle is stuck closed.

Did you mess w the Air/fuel needle at all?

 

[ShortyLaVen]

I was totally unaware of this Hondabond... good to know! It is the head cover seam, I didnt have my coffee yet haha. It still looks like a tweeker gobbed it on there to me tho, but I suppose it could have been an overzealous mechanic...

I will double check for spark and compression. I kniw the float bowls are full, I've double checked that already. Thanks so much for your help, and thanks even more for baring with me!

 

[ShortyLaVen]

Just got home and started testing. Spark, good. Compression, 120 on both cylinders, checked with throttle wide open and electric starter. Points and timing checked and rechecked once more. Fuel in bowls checked and petcock checked. I'm going to top off the tank to see if the extra pressure helps out at all. Maybe the bowl fills while sitting but its not drawing enough fuel when running?

Also, here's a pic of the goop around the cylinder head. Note that there is none on the right side, only the front and left (I'm going to assume this isn't a big issue and someone was just trying to stop an oil leak). I also noted that my case was stamped as though the cam chain tensioner was replaced, maybe this was the work of a lazy dealership mechanic?

 

[trek97]

wow, yes thats a mess.

if the bowls are full and floats are set to 18.5mm it will have plenty of gas to idle a couple minutes. even w tap shut off.

if you got spark at the plugs and timing is close it should start right up and run.

idk ???...pull the carbs, clean and check a/f & pilot circuits.

 

[ShortyLaVen]

Got it to run on both cylinders!!! It was the petcock as it turns out, wasnt feeding both lines properly. The line to the right carb was flowing strong, but the other was just a trickle. Enough to fill the bowl after sitting a bit, but not while it was running. Now that I got that figured out, I took it for a ride. The bogging still persists between 3 and 5k... im thinking I need to sync the carbs? But I dont have the right nipples for the vacuum ports. Is there anything else I can use for this job? I sent a PM to the fellow here that makes them, but I'd like to figure something out in the mean time..