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Discussion Starter · #1 ·
So its been a while since I last had issues with the CB360. I took it to a guy on my local forum who specializes in vintage bikes. He tweaked my clutch, adjusted valve clearances to spec, and synched my carbs for a low price. The bike ran perfectly for a few weeks. Now I am down to a single issue that has plagued me before:

Anytime that I ride the bike for an extended amount of time (longer than 25 minutes) I have issues with idling at stoplights. The revs will go down to the 1.3k range and stay there for a good 5-10 seconds. Then it will start to stumble, stutter and the bike will die. I can restart the bike right afterwards with no trouble, but to keep her going, I need to lightly apply throttle to 1.5-2k RPMs to stay "alive". I thought about just adjusting the idle screws to a higher RPM this is probably bad for the engine and plugs.

What could be the possible culprit? Compression is good (155 left, 160 right) carbs are rejetted and synched, spark plugs are slightly dark but otherwise good. Someday I am going to try out a new condenser that I had lying around, and I have a new battery and plugs coming in sometime in the mail. Thanks in advance!
 

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I'd say you're on the right track thinking about the battery, and condenser. Also, it might not hurt to re-check that carb sync. Although it does sound like something electrical or battery related..

Also, new plugs never hurt anything.

GB :mrgreen:
 

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Discussion Starter · #3 ·
mmmhmmm...
I was "google"ing this problem and I saw a bunch of responses on motorcycle and car forums that the problem is the condenser overheating and on its way out. I don't know why I didn't replace it when rebuilding the ignition. I will give it a shot this weekend.
 

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Discussion Starter · #5 ·
So I had some time today to mess around. All I did was install the new condenser from MikesXS. Is there a wrong way to install a condenser? The MikesXS one had both wires the same color. I hooked it up one way and the bike was able to idle, but any throttle made the bike die. I flipped the wiring and the bike "ran" as it did with the old condenser.

I will do a testride some other day
 

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krukster86 said:
So I had some time today to mess around. All I did was install the new condenser from MikesXS. Is there a wrong way to install a condenser? The MikesXS one had both wires the same color. I hooked it up one way and the bike was able to idle, but any throttle made the bike die. I flipped the wiring and the bike "ran" as it did with the old condenser.
I'm going back over 30 years to my Navy "A" School training, but I don't think the condenser (which is really just a capacitor) is polarity sensitive. If it was an electrolytic capacitor then it would be a different story, but for our purposes I think you can hook it up either way. Keep in mind my memory is failing me these days.
 

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Discussion Starter · #8 ·
Yeah I think you are right. I tried swapping the wires back to how they were at first and I had no problems. I guess maybe the condenser was improperly grounded or something.
 

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Discussion Starter · #9 ·
I decided fuggit and went for a test ride. I saw no change in performance when riding. I went out for about 20 minutes, didn't get a chance to idle at any intersections. So I pulled into the driveway, pulled up a chair and let the bike idle for a minute (literally), sure enough it would stumble a bit, recover for another 15 seconds, stumble and then it died. I don't think it is a condenser problem, but what the heck I have a new one now :cool:

Anywho I will have to wait and see what happens with these new plugs and the new battery.(still "order pending completion" according to OldBikeBarn :evil: )
 

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krukster86 said:
Is there a wrong way to install a condenser? The MikesXS one had both wires the same color.
Not in this case - the two wires from your stock condensor are blue and yellow - coresponding to the blue and yellow point wires. The new condensor wires can go to either one. There are actually two condensors in a single unit.........
In this case, the capacitor grounds through it's case to the coil frame to the frame itself.

Did you powdercoat or anything???
 

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How about new coils? Didn't read your entire build thread but did you keep the original coils or replace them with fresher ones? It's amazing what new coils will do for your ignition. Ever since I installed a pair of Dyna 3 ohms in my 350, the ignition has been amazing. NIce, powerful combustion and rock steady idling. I also used a hotter plug, B7ES and the electrodes are now a perfect tan colour.
 

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Discussion Starter · #13 ·
The frame is not powdercoated. Hopefully the new parts will solve the issue, if not/until then I can just deal with this little quirk and move on with riding the bike
 

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My 350 is doing the same thing, running sweet but, at idle she will be doing fine then stutter and stall.
I think the sync is out and I am going to put the holes in the head for sync screws to use my Morgan Carb Tune.
My buddy Edgar set the carbs up for me initially but, the idle was too high once she really warmed up and I messed with the adjustments and screwed it up.
Two Morgan Carb Tune syncronizers will syncronize all six of my CBX carbs, I am sure I can make two of them work for my Scrambler.
 

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Discussion Starter · #15 ·
A feller I bumped into at the Mods vs Rockers show in Chicago on a CB350 ranted about the same problem. Whats funny is he was in back of me when I was pulling into the street of the event, and our bikes stalled at nearly the same time while waiting to be directed to a parking spot. He says that for daily riding he sets the idle to be high (nearly 2k) and doesn't have problems.
 

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Discussion Starter · #17 ·
Not in great detail. I hooked up a multimeter to the battery and revved the engine at different RPMs and saw the volts perk up to the range indicated in this diagram:
http://www.electrosport.com/technical-r ... iagram.pdf
I am going to try this again since last time I did this was months ago.
 

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Discussion Starter · #18 ·
OK checked the system: more than 13.5V at 2500 RPM and lower than 14.8V at 5000 RPM. So it looks like that is in the clear!
New spark plugs are in stock, battery is on backorder at OldBikeBarn. I am hoping those will do the trick. If anything else I am going to clean the points.
 

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krukster86 said:
OK checked the system: more than 13.5V at 2500 RPM and lower than 14.8V at 5000 RPM.
New spark plugs are in stock, battery is on backorder at OldBikeBarn. I am hoping those will do the trick. If anything else I am going to clean the points.
You can just use jumper cables and leave them connected to verify operation. If the batter is bad then it'll run poorly until you get a good battery.

A lot of people think you can't jump start or leave a car battery connected to a motorcycle batter and that is simply not true.
 

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Discussion Starter · #20 ·
er what? :? sorry I am not really following what you are trying to say there Mike
 
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