CB 360 no label parts build!

Mmmm cylinders bored. Nos .75 pistons ready to fire
 

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I was digging through the bin of parts that came from Po and these gauges were new in box. Score or not? Don’t know anything about them. This tach doesn’t have any tach cable input so I’m guessing it goes with some electronic sending unit which I don’t have.
 

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Just learned from YouTube that I can tap into my coil wire and it will read the spark which represents a revolution of the engine. Learned something new. I think I’m gonna use them because I have them. If they break because they suck I will just replace.
 
Stayrad said:
Just learned from YouTube that I can tap into my coil wire and it will read the spark which represents a revolution of the engine. Learned something new. I think I’m gonna use them because I have them. If they break because they suck I will just replace.
Mine is just a sensor wire that wraps around the plug wire. No need to cut anything open.

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So I just bench tested the engine .....getting smoke out of the left cylinder. Everything is fresh so I’m banging my head against the wall on why this would be happening. All I can come up with is that the cylinder was overbored, forgot a valve seal, rings weren’t aligned right. My answer to all these things is “surely not”

I’m about to break it back down. Any advice from the cyber world before I do that?!?
 
Great thread!, and perfect timing as i’m about to do a top end rebuild on my 360.

What pistons did you use, .75 oversize gs850 pistons??

Steve
 
I actually am just using CB360 pistons at .75 over I’m about to do the top end today to figure out why I’m getting smoke out of the left cylinder.
 
Did you oil bores when re-building? Rings are on right way up and in correct positions? New valve guide seals?
 
crazypj said:
Did you oil bores when re-building? Rings are on right way up and in correct positions? New valve guide seals?

I didn’t do oil rebores I broke the engine down yesterday and the ring gaps were not 120 degrees off. I must have moved them on accident when installing cylinders.

So I put them120 degrees apart fired it up yesterday and now I’m only getting a small amount of smoke out of both when accelerating. I’m hoping that’s just because it’s a fresh build. compression is good. The cylinders do have the cross hatch pattern after bore so I’m hoping those are holding a little oil that’s burning.

Now my next prob is the Charlie’s place electronic ignition

Turns out 360 has 2 different types of spark advancer. Mine is the one that has 369 stamped on it. Not only that but mine is one of the 5percent that is stamped on the opposite side. So much wasted time figuring that out.






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Rings not spaced at 120 won't cause oil burning. It's more likely second ring is in upside down plus they need bedding in which is why it's already less smoke than it was originally
 
CB 360 no label parts build!

crazypj said:
Rings not spaced at 120 won't cause oil burning. It's more likely second ring is in upside down plus they need bedding in which is why it's already less smoke than it was originally

Cool, by end of day today all smoke was gone.

Now to tuning. Ugh!!!!! I hate this part. Feel like I’m running in circles.

So far....
Cam chain tension - check
Valves - check
Timing - perfect (Charlie’s place ignition)
Plugs - new
Coils - good

The problem
Starts easy and idles perfect
Goes flat at 1/4 throttle or less

Thought it was jets so I tried every combination. Currently running 145 pilot and 160 main 2 turns out

Now I’m thinking it’s the advancer
Springs are tight and pull back but maybe too tight.

The reason I think advancer is that I tightened the cam bolt that holds the advancer on. Slightly over finger tight and it ran horrible. I loosened it to confirm that the advancer could flex and it ran better but still can’t get past quarter throttle.




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Are you using Mikuni VM carbs? It isn't possible to jet stock Kei-Hin to work with K&N or Uni's and cheap pods just restrict airflow over 6K
 
crazypj said:
Are you using Mikuni VM carbs? It isn't possible to jet stock Kei-Hin to work with K&N or Uni's and cheap pods just restrict airflow over 6K
Ya they are vm30s


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The pods are the ones sent with it from dime city. They don’t look like they cover the holes. Also it’s flat just revving it without the pods


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VM30s really are much too large for the CB360. that may not be your issue entirely but it's contributing
 
MiniatureNinja said:
VM30s really are much too large for the CB360. that may not be your issue entirely but it's contributing

So I messed with advancer tonight and it seems to be working right.

What is messing with my head is that it idles perfect. Starts up immediately and idles like a champ.

Just for fun I tried a 45 pilot and a 170 main and it did this weird thing where it would die when I took bike off kick stand and held upright. When tilted on kick stand it would idle.






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You need to go through carbs and check things like float levels, etc.
There is a ton of (mis-) information on VM30's. If you fit new plugs and just let it idle, they will be black within a minute or so, pilot is probably too big Plugs are almost always 'dark' but shouldn't be sooty.. A major issue is the slide cut-away, it's too big in stock carbs so air speed drops as throttle is opened. Low airspeed means you don't get fuel drawn up emulsion tube and motor cuts out.
'Conventional' carb tuning doesn't really work when your pretty much starting from scratch (normally you fix main jet size then work backwards, fine for racing but not so great on the street where you need low/midrange~80% of the time)
 
Super helpful. Thank you I will try that. Would you say it’s possible to get the vm30s tuned for regular street riding?
 
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