I'm no expert, but my 1979 has copper core plug wires and 5K Ohm resistor plug caps. You shouldn't need resistor wires unless it's interfering with your communications devices.

I work in a m/c shop and one of the most common tuning mistakes we see is people adding resistor wires "because that's what they had". If you aren't absolutely aware of the need for those wires, that is, if they were simply on the bike when you took delivery, then I'd get rid of those ASAP.

Note that some Electronic Ignitions require 5K Ohm plug caps, but used with copper core wires.

i make my own cables, using copper core ignition, Packard wire, an NGK 5K caps, every connection is soldered and water tight. as has been mentioned resistor plugs should not be used, they cause MORE resistance and a weaker spark to fire. carbon cables are a NO NO.

if you zero your VOM, if it's not digital, it reads 0. if you place a copper ign. wire of 2' between the leads it's 0. if you add a 5K cap and test again it reads 5K. ... if you read less than 5K with this set up you have a degrade/ resistance/ corrosion issue.

He really did not say he had carbon resistance wires. perhaps he was just measuring from one end to the inner spark plug cap connection.

I put my handy multimeter on my 1k cables, and see 860 ohms on the R, and 945 on the left.

It's fairly clear he said he had "1K cables", which I interpreted as 1K Ohm since he measured near that on both sides with an Ohm meter.

If he was measuring through the cap, I'm not aware of a 1K Ohm cap. Both the original equipment and the more common NGK replacement caps are both 5K Ohm.

This occurs once a week at the shop, so I don't think it's jumping to conclusions. Previous owner suspect they need new plug wires, so they run down to the local auto parts store and say "gimme 2 sparkplug cables", not knowing to specify copper core. When they can't get the bike to run right, they sell it and blame it on the carbs.

I had wondered about that "1K"...thought it possible he had resistance wire....then thought that maybe he has the silicon insulated cables with the resistor caps, I saw some with a funny looking "1", followed by a serif K, and some sort of unidentifiable symbol (very small)... that were not resistor types. I'm not sure who made and sold them. I have a photo here someplace of those cables. My guess at the time was that they were shortened versions of some sort of car cables. I looked pretty carefully at the coil ends of those cables.
Real carbon cables can cause problems even if they measure OK....but somewhat rare unless quite aged.

Update...
I have an /7 with points...the spec for this bike is a 1k cap, which I did replace from Motobin, for my bike. ( I didn't buy them from the local auto store..???) Please be aware I'm new to all of this, and likely say one thing, mean another. My apologies. Yes, I know 5k cap is the more common, and my bike could run that version fine, from my reading.
My measuring was from cap to end of each cable. In retrospect, I realize the flaw in my thinking. I have a better understanding now about resistance in cables. The reason I posted was I was trying to run down a problem. While my existing cables were a bit "tired", they were not the problem. I did find a reference from Snowbum that there is about an 20% variance on ohm's in caps. My mistake was equating ohm's with "connection quality".

The issue is likely the diaphram on the R carb. It basically was coming off the slider. My advance unit was very grotty as well, needs serious cleaning and lube, along with finding washer replacements. I have ordered a replacement diaphram, which also includes the slider and needle jet. The flat top carbs on the 80 /7 seem to have the "all in one" units. ATU maintenance underway as well.

Again, sorry to start a thread with an odd question, that really has no relevance. I have learned a bunch though, so all is not lost. At least for me.

Robert,
Sorry, I referenced you without a citation. I didn't put this all together until just now, you jumping into this thread. Anyways, you deduced my poorly explained/understood approach.
For fun, I did test the new cables, the ohm's are very close to 1k, cap to cable end. Cap to cap, through the coil is 15,400 ohms. The existing cables looked to be fairly old, so replacing them was as much "piece of mind" than anything. Sure, hope was there for resolution, but based on ignorance, not experience.
The real issue is running wonky above 4k rpm, ohm question was just a starting point. Not well thought out in retrospect.

Looking forward to installing spiffed up ATU and new diaphram in R carb. Should run better... 🙂

The real issue is running wonky above 4k rpm, ohm question was just a starting point. Not well thought out in retrospect.

Looking forward to installing spiffed up ATU and new diaphragm in RH carb. Should run better..

14792 -
No apology needed. It was a very good explanation. I will apologize for the bunny trail off to resistor/ carbon/ suppression sparkplug cable land.

In my defense, and for your future reference, remember that the carburetors are the only part of a motorcycle that are adjusted while the engine is running (that is, in a dynamic state). Therefore, before any type meaningful carb adjustment can commence, all other static tuning adjustments must be verified as perfect. That means timing set, ATU lubed, new sparkplugs, valves adjusted, and YES even sparkplug cables and caps inspected. So you were 100% on the correct track.

Additionally, you should note that it is best practice that whatever is done to one carb, should also be done to the other. This motorcycle is a "twin", as in "identical". One way to reason through this is understand that whatever caused the diaphragm on one side to rupture has been done equally to the other, whether this be age, fuel additives, or number of up/down movements.

Speaking of fuel additives, I highly suspect that the common fuel additive known as Seafoam destroys diaphragms and o-rings. So if that is the cause of the burst diaphragm, then you also find some o-rings in need of replacement.

Hope this helps.

Thanks Wobbly,
Yes, several experienced inmates have strongly opined that the static tune up bits are the first stop with troubleshooting. Roger that. Also, I'm likely to replace the other side as well, first looking to solve/confirm my problem. (That and they're $80 a pop.)
I think my issue was that of the diaphram coming loose from the slider, not breaking down with holes in it. I believe it was a shadetree replacement, and simply came loose, then stretched out a bit. Because I'm new at this, I opted to buy a replacement unit and avoid the shadetree reattachment process for now. Grazi for the seafoam tip, haven't used that. With ethanol gas being almost as bad, seems like rubber bits don't stand a chance today.

Excited to feel the acceleration of the mighty 80/7 once again. That and going over 50 mph will be fun. Expecting to be up and testing by tomorrow. Supposed to be decent weather ...yea.

That and they're $80 a pop.

At that low price, a good friend would buy us all a set !! 😆

Best of luck with the repairs. Have you made yourself the homemade vacuum gauge for balancing the carbs yet? That will really help you finish up the carb adjustments in a first class manner.

In place of Seafoam, if you only need to stabilize the ethanol, try Stabil (Wal-Mart) or StarTron (Home Depot and boating supply houses, like West Marine). They're also both excellent in your gasoline powered lawn and garden equipment.

Last thing... I live in a county with more farm animals than people. After an episode of spark knock and poor running I've learned to bypass the local gas station, and drive the 7 miles into town to find a station that pumps high test on a regular basis. Otherwise you may get a slug of ethanol way over the limit.