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Discussion Starter #1
Did the early CB/CL 350 have resistor spark plug caps? I replaced mine assuming they were, but someone told me Honda didn't use resistor caps on them. So, if I have resistor caps on a bike not designed for them, do they compromise the spark strength (I still have all original ignition components)?
 

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Assuming the coil is up to par,to begin with, building up the extra charge to overcome the resistance will just produce a slightly hotter spark. No different than widening the gap a little to produce cleaner low speed running (a little fatter spark helps things burn cleaner). In the late sixties, new bikes came out of the crate with a two piece metal cover over the plug caps, most likely for static suppression. We popped them off an tossed them in the trash when we set up the new bikes, so you wouldn't get shocked when you rode in the rain.
 

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Yes they did. They are a 5k ohm cap.
Did the early CB/CL 350 have resistor spark plug caps? I replaced mine assuming they were, but someone told me Honda didn't use resistor caps on them. So, if I have resistor caps on a bike not designed for them, do they compromise the spark strength (I still have all original ignition components)?
Sent from my Moto G (4) using Tapatalk
 

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One way to be certain is to take a multimeter and test your caps.
If they are non-resistored then you should not be getting any (or very low) ohm readings at all.
 

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Discussion Starter #5
I have new NGK resistor caps on it now, but was wondering if they were correct. Plugs look like the bike is running rich, so I was thinking the spark might be a bit weak for some reason. New OEM air cleaners, stock jets, carbs synched and tuned, floats at the correct level, valves adjusted, timing is correct, advance is working. I'm at a loss as to why it's rich. It runs great and revs freely as high as I dare take it, plenty of power. Idles perfectly, instant response when I blip the throttle at idle.
 

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You could try raising the float level (lowering the fuel level) a mm or two. That will lean out the mix.
 

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What plugs are you running? What exhaust? Stock air box?
 

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Plugs are not the final judge. If not fouling, and it's running great, don't try to fix what doesn't need fixing. Plug cuts are just an indicator. If really worried, have the exhaust analyzed.
 

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Discussion Starter #9
I'm running BP7ES plugs to keep them from fouling. Stock air boxes, stock CL exhaust at first, and then I changed to stock CB headers with Emgo Dunstall copy mufflers. The rich condition was present with both exhausts, but it does run better with the CB exhaust. I am planning on adjusting the floats to lower the fuel level in the bowls as a last resort.
 

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You might want to consider going with Iridium plugs and non-resistored caps. I used to have an overly rich condition on my bike also and the B8ES plugs I used kept fouling all the times.
Then I switched to non-resistored caps and iridium NGK'sw and not a problem since. The bike runs better also.
 

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regardless of whether it makes sense to you or not, fuel level in the bowl plays a role in fuel/air mixture.
 

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regardless of whether it makes sense to you or not, fuel level in the bowl plays a role in fuel/air mixture.

+1

The jets are the size of the straw through which the fuel is sucked. The float level controls how far up the fuel starts. The higher the fuel level, the less vacuum that is needed to pull the fuel into the carb body. So if the fuel has an easier time getting into the carb body, then you run richer across the board.
 

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Discussion Starter #14
Well, I bought some non-resistor NGK caps and installed them today. They are smaller than the 5-ohm caps, about the size of the originals that came on the bike, so I'm guessing that a '69 originally came with non-resistor caps. The bike started easily and idled nice, so we'll see, I'm riding it some tomorrow and will see if they make any difference.
 

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Discussion Starter #15
Thought I'd update this post. The non-resistor caps made no difference. I'll be pulling the carbs off in the near future and adjusting the float levels a couple millimeters more and we'll see what happens.
 

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The lack of resistor caps would only piss off they guy listening to his radio next to you at the traffic light.
They suppress the raido interference noise.

Too much resistance will be a probelm but not having any shouldn't make much if any difference.
 

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The lack of resistor caps would only piss off they guy listening to his radio next to you at the traffic light.
They suppress the raido interference noise.

Too much resistance will be a probelm but not having any shouldn't make much if any difference.
The majority of plugs sold today have the resistors built in, I find it strange that you can't seem to find non resistor caps in the US for most of our bikes.
 

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Discussion Starter #18 (Edited)
Update: I took the carbs off (again) this past weekend and dropped the float level from 26mm to 29mm. The bike started and ran ok, so I took it for a 2-mile spin around the neighborhood. When I returned, I pulled the spark plugs and they weren't black any more - the insulators were white. Way too lean, so I'll take them apart again and change the level to 27.5mm and see what happens.

5-17-19.jpg
 

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The majority of plugs sold today have the resistors built in, I find it strange that you can't seem to find non resistor caps in the US for most of our bikes.
NGK non-resistor plugs are available in the USA at most ALL chain parts stores, and the caps available from most sites that supply the 4s like 4into1.com and cb750supply.com
 

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Discussion Starter #20
One last update to this old post. A couple months ago I reset the float levels one more time (to 27.5 mm), and now the plugs look spot on. Bike runs great, too. Strong through the entire rpm range, no spitting or stumbling, immediate idle drop to 1100 rpm when the throttle is closed. I'm a happy camper with the carb problems finally out of the way.

6-7-19b.jpg
 
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