75 CB360 Done but with a carburetor issue

MiddleClassChops

MiddleClassChops

New Member
Hey guys. Finally got my CB360 to an almost ride-able condition. Here are a couple pics.





Has a little issue when running, here are all the pertinent facts. I'm at about 3000 ft elevation. The carbs have stock jetting 35, 68, 100. Pods and open cocktail shakers. Timing and valves have all been double checked and the coils are brand new XS650 coils. Here's the problem. I'll start the bike up and it will run and idle like a champ. I'll roar off down the road but most of the time when I slow to stop, it will die and then there's no getting it started again. I was thinking maybe clogged slow jets and was also thinking I want to throw some mufflers on, maybe 2 from a CB750 to quite it down and help with back pressure. You guys have any other input? I've been through a ton of threads in the past few days and have found some helpful info but wanted some personalized advice.

Thanks
Kellen
 
Good Work on the bike! Looks clean and that seat's rad. Are you sure you're getting fuel to the carb? What do the plugs look like after it dies?
 
Thanks! The seat is Ostrich leather that I had around for another project. I think I'm getting good flow on the fuel. If I pull the lines and open the petcock, it flows normal. I'll need to run it again and check the plugs. The last time I checked the plugs was before I replaced the coils and they were black and wet, but hopefully should be different now.
 
You have stock jets, pods (get some good ones, it will never run right with those), and an open exhaust. Recipe for shitty running.

You need to rejet. You're probably running way lean, and as a result running too hot and overheating.
 
Thanks for the input SONICJK. That's good advice. I'm running EMGO pods right now and do want to throw some mufflers on. With the pods combined with the elevation, think I should probably go up 3 sizes on the primary and secondary.
 
Leave the primaries alone. It is a rare day when you have to change out the primaries on these carbs.

I'd bump up to 110 on the secondaries and see how it does. You'll never get these carbs running 100% with pods, only with the stock air box or by having crazypj mod the carbs to handle the pods.

Your elevation shouldn't require too much in the way of extra fueling, so don't go crazy with the jetting, either.
 
Sonreir said:
Leave the primaries alone. It is a rare day when you have to change out the primaries on these carbs.

I'd bump up to 110 on the secondaries and see how it does. You'll never get these carbs running 100% with pods, only with the stock air box or by having crazypj mod the carbs to handle the pods.

Your elevation shouldn't require too much in the way of extra fueling, so don't go crazy with the jetting, either.
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Elevation would be less fueling no? Less air less fuel.
 
That's correct. What I meant to imply is that because of his elevation, he shouldn't need to upjet all that much.
 
He said his plugs were wet and black before so I would assume they would be similar even after the coil change. It leans me away from it running lean.....get it. ;D
 
The color of the plugs don't mean much unless a proper plug chop was done. Just driving around and then looking at the plugs doesn't tell you anything about your fuel/air mix.
 
Sonreir said:
The color of the plugs don't mean much unless a proper plug chop was done. Just driving around and then looking at the plugs doesn't tell you anything about your fuel/air mix.
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WHAT? Maybe not in every instance but most of the time there is some indication on the plug if there is a fuel issue. I know you know your stuff but saying that is slightly ridiculous.
 
Alaskanrocket said:
WHAT? Maybe not in every instance but most of the time there is some indication on the plug if there is a fuel issue. I know you know your stuff but saying that is slightly ridiculous.
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It may tell you "generally" if you have a fueling issue, but as far as tuning goes, that won't tell you shit.

You have to do plug chops to get an accurate reading at each jet "stage" (if you will)
 
Back up a little shall we. For sure, checking the plugs and finding them dead dry or soaking wet does tend to indicate a problem but plug choips ONLY work at WOT because that's the only time you have the plug at its operating temperature. Anything less than that doesn't tell you much at all. Yes you can make the plugs change color, but you have no idea what the motor wants of what it's getting. At lower laod plugs should not be Krispy Kream color or some Starbucks color. The tip should be white (clean - not boiled) at WOT with a 1-2mm mixture ring at the base of the porcelain.

At lower revs and lower loads, it's not telling you much outside of very coarse indication. It won't get the jetting right.

Send your carbs to PJ and beg him to modify the air jets for you and fit whatever filters he says work.
 
Thanks for all the input. I built this bike with very little time spent int the forum so the issue with CB360s and pods is pretty new to me. I'd like to send them to PJ to get worked over so I'll wait till he sees my PM. I'll see what advice he has on filters other than stock.
 
For the record I just want to say it wasn't the original poster that was throwing a shit fit. That would be me. :) So nobody be mad at him, just me.
 
SONICJK said:
Elevation would be less fueling no? Less air less fuel.
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Actually less air at elevation causes rich running. At higher throttle settings, the lower air pressure also leaves the slides lower....this leans it a bit....For his elevation, stock jetting is about right, and slightly rich (this is assuming stock) at isle and low speed jet area....
CV carbs are somewhat self adjusting for elevation....A little rich down low and right mid throttle up is usually O.K. stock...

His pods may be blocking air intakes, the emgo's are small and may cause rich running.

The only real way to tell is check the plugs....


Edit: Maybe you meant there was less fuel needed because there was less air, if so, you were correct...Read it quickly and realized later you may of said it in a way that confused me...I get fuddled sometimes...LOL
 
Michigandude said:
Where do people put the battery with open middle frame?
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I have a tiny little 2.5ah battery that you can see in my picture. I welded a little platform for it to sit on just behind but between the rear motor mounts.
 
The problem is...The pods. Its gonna run rich midrange (3000-5000)rpm.
The smaller 100 main secondaries are a bandaid to correct this problem.
Anything above 4500 or so, and its gonna be lean, WAY too lean.
She probably wont do over 6500 in any gear OR 70mph in 5th or 6th for very long, before she starts popping and getting hot.

If you install 110s or more, this will help w upper rpm lean condition. However, She will start cutting out and fouling plugs during midrange rpm operation.
 
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