Cb360 Reassembly Help

cb360j said:
Lol thats for sure! I swear I can pull the entire engine out in twenty minutes then have the bottom end taken off in another 20 or less. There was one day when I was replacing the kickstart shaft that I removed then stripped the bottom end 2 times in just a few hours. Then I had to again when I felt like it didn't feel right.. again.. And then there was the first time I took it out of the frame. And ive taken the top end apart at least 7 times. cb360s are the most labor intensive motorcycles I swear

Ha, you'll get it right eventually. I had to open my 360 engine up 3 times before I got it all squared away - it was also my first build so there was a learning curve.
 
cb360j said:
Lol thats for sure! I swear I can pull the entire engine out in twenty minutes then have the bottom end taken off in another 20 or less. There was one day when I was replacing the kickstart shaft that I removed then stripped the bottom end 2 times in just a few hours. Then I had to again when I felt like it didn't feel right.. again.. And then there was the first time I took it out of the frame. And ive taken the top end apart at least 7 times. cb360s are the most labor intensive motorcycles I swear
Nope, 350, 450/500 are much worse in my opinion. With those you have to remove engine every time you need top end off. As you've found out, pulling engine is a quick process on 360 :mad:
 
Maybe labor intensive wasnt the right word. They are the most finicky. They refuse to run right unless very very particular conditions are met lol, they remind me of drawing in solidworks. I am constantly having to fix rebuild errors. I had a 2001 ducati 749 that when removing the fairing, though it was little twisty d ring things... WERE SUCH A PAIN TO PUT BACK ON. Changing the oil on it was even a little annoying,.
 
You'll be a 360 expert soon enough then 'everything' on them is quick and simple ;D
 
cb360j said:
They refuse to run right unless very very particular conditions are met

Once you hit her sweet spot. She will run super for years of fun.
 
crazypj said:
Yeah, makes life a little boring when they get reliable ;D

Ha, Im currently planning phase restoration #4 for Cherry bomb now!

Making her into a completely different machine...AGAIN.

Kinda overwhelmed at the moment though. As I'm Also planning phase #2 for the Black Knight.

Then Id also like to re-paint Piglet. hahaha
 
trek97 said:
Ha, Im currently planning phase restoration #4 for Cherry bomb now!

As I'm Also planning phase #2 for the Black Knight.
These statements made my day.
 
Back up and running! :) Soooooooo last night I took the top end back part, the cam chain tensioner (the actual bottom piece) had moved when the initial destruction happened. So I threaded a piece of all thread in it and pulled it down. Fixed it. Compression still seems low, and I think A leaking head gasket could be to blame. I can see some bubbles coming from between the head and the jugs when it’s running for a little bit.
Also, got a little bit of popping out of the exhaust. And fuel comes back out the left carb a little. Any ideas? Maybe a bad head gasket is to blame?
I’m gonna retime it tomorrow to hopefully elimate the popping. Also going to re set the valves just to cure some boredom, and hopefully that will make the fuel stop coming out the back.

These stupid points that I bought from common motor, after the last set broke, are beginning to break exactly like the last set so I’m a little irritated with that. I’ll have to try and find a genuine Honda set.
 
Did you use a split cam chain w master?

You could have checked valves for leaks by filling the intakes and exhaust ports w alcohol, letting them sit for 30min - 1hr.

Head bolts can benefit from being torqued to spec then sit 24 hours, then, one at a time - relieve and retorque again to required spec.

Ive got OEM Honda points - never an issue.

If it has a bent valve there's a chance you will need a new valve guide since running it.

Example of testing for valve leaks in my 400F w alcohol through intakes and exhausts filled w alcohol, after honing valves.

11494-031118094009-462054.jpeg


11494-031118094009-46221419.jpeg
 
OEM or aftermarket head gaskets are not designed to be re-used, (although people do and 'get away' with it) it's another reason I much prefer solid copper , they pretty much last forever. Check the 6mm bolts at ends of head are torqued properly plus are not stretched or otherwise damaged. (pull, plugs and use a box end, they should only be about 9/ft /lbs) It's VERY easy to over tighten and either strip thread or stretch bolts, I remember checking 6mm bolts (long time ago, probably 1980's?) of the techs in shop everyone (averaged) about 14ft/lbs, myself included. I got a lot more careful after that, 72~110 inch pounds feels like it's going to fall out but is correct (although it was probably another 20+ yrs before I bought an inch pound torque wrench- which I rarely use - even today) I would re-check everything before deciding to pull it apart again, rushing means you may have something close but not right. When testing valves with alcohol, 30 seconds is more than enough, in fact may books used to say 10 seconds as valve is never closed that long in a running engine plus valve head and seat work harden as engine is running
 
I did use a split cam chain with a press in master link. Don’t let anyone tell you it’s easier, it’s just as hard as splitting the engine.

I’m thinking I’m going to take the engine apart, though I don’t have a compression tester I don’t feel any compression on my finger when rotating through on left cylinder. , it would just make sense to check the rings and the valves anyway. Hopefully I don’t have a bent valve, even though it would be the easiest to fix... the machine shop here takes forever to get things done and if I’m replacing one valve would it make sense to go ahead and do every single one of them?
I’m just speculating since nothing is apart at the moment
 
It doesn't make economic sense to replace all the valves if they are OK although fitting oversize intake valves is a good idea (exhaust valves don't need the 1mm oversize, they could be even smaller than 28mm and you wouldn't loose power) Because the valve stem is pretty big diameter it's very difficult to bend valve bad enough to crack the guides, I've only changed them when worn oversize and even then rarely as very few engines got high enough miles (but a lot of abuse)I don't mind revving pretty stock motors to 11,000 or more in my bikes (but the 390 didn't get much over 9500 as it had 'heavy' pistons, wasn't sure rods would take it))
 
Question:

In the manual it doesn't say anything specific about when adjusting the cam timing that when you tighten down the cam sprocket to the cam, the left cylinders lobes need to be pointed down towards the engine. Is this something that is absolutely necessary? I didn't pay attention to this when assembling, just set the cam timing, then bolted the sprocket on, then turned the engine over where the lobes were all pointed down then re installed everything.

Could this be the reason I was getting fuel pushed out the carb? The valves work properly. Ah! Just keep finding reasons to take everything apart. that will ensue this afternoon.
 
If you did cam timing properly it will be exactly like in manual. As long as the 'line' on cam sprocket was completely level (or very very slightly tilted down at front to compensate for new chain) it will be fine as on the 360degree rotation the lobes will be up at TDC. (valves on overlap) The only time its a problem is when your a tootrh out (as you found out already)
 
Well. The cam timing was perfect. I had a sneaking suspicionabout that left cylinder intake valve since it was pushing fuel out of the carb.
Bent valve. It was super difficult to pull out of the valve guide.

I pulled the head off. And looked and the valve was sorta pushed up. I shined a light in the intake and light shines all the way around.
The framing square is all that I had that was perfectly straight for reference. When I roll it on a piece of granite it “bumps” every time it rolls. So to me that means bent. All the other have no issues though.
 

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