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CB200 carb issues

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Oddjob:
NGK caps are supposed to be 5K resistance. You could try measuring one and seeing what it is and then when it's hot to see if it changes.

Just bought some NGK caps for future use, might as well get them whilst they are available, seems it's something to do with the stuff the body is made from, shortage or no longer made I believe.

Sesman:
Yes, Ken. I can believe it. I had to wait 4Months for the last lot…yes, 4 months😳

McCabe-Thiele (Ted):
Looking back on the post not sure if you need higher or lower coil resistance - be handy if you knew what they were when the bike was built so you could source the right one.
Probably not relevant but as V= IR a lower resistance would mean a bigger current ?
Would higher resistance meaning lower current demand help supply more spark at higher revs - I'm way out of my depth here just thinking out loud in the hope it can help.

IIRC the 400 runs on 4.6 Ohms so if a 200 has half the cylinders & 1 coil would that be a similar  sort of figure?

My online search suggests the CB200 coil is 4 ohms according to the below three sellers.

.https://www.amazon.com/Ignition-Coil-Honda-CB160-CB175/dp/B079M69MW1

.
https://4into1.com/ignition-coil-honda-cb-cl160-175-200/

.
https://www.aliexpress.com/item/1005003463624926.html

Sesman:
Hi, Ted. Unfortunately not. The voltage on the secondary HT side is a function of the coil inductance ‘L’ and the rate of current collapsing when the points are opened. The resistance of the coil simply self limits the primary current and alters the collapsing current time constant….The trick with coils is to ensure that the secondary HT side insulation is sound. The magic in coils is much, much more to do with transformation ratio (eg the number of primary/secondary turns and the quality of the transformer core (yoke) material and design. That gets us the ⚡️. Energy is a function of  voltage squared/ resistance x time. The voltage on the secondary side is very large, but so is the coil secondary resistance.The time is very short of course (joule integral). Basically that’s what produces the bang.

I could be wrong, but I’m sure there is a thread somewhere, where Ash constructed an ignition coil tester to simulate the ignition process and coil performance. Apart from open circuit (continuity testing), I’m guessing the most common cause of failure is insulation failure, whether that be in the coil structure our downstream on the HT leads, caps and plugs.

Just for completeness, the back EMF created in the coil primary circuit as a result of collapsing current (points opening) drives a current. It’s this voltage and current that arcs across the points causing damage to the points surfaces. That’s why it’s important to have a good condenser (capacitor). The arching also extends the collapsing current time constant, which is counter productive to good spark production.

I know, I know. A tedious subject that many are fully versed on, but if it helps somebody out there to understand the basic mechanism it will improve their fault finding. Apologies to all who may feel patronised, this item was not for their benefit.🫣

Johnwebley:
Thanks gentlemen,
When it gets a little dryer and warmer I shall check all my plug caps for resistance,

What is the refresh rate on the coil?

Can you estimate how many times a second is to many?

The difference between 4 and 5 ohm,

Back later

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