Coil help xj700 maxim 1985

Hi.
I have tested the primary and secondary resistance to find both secondaries open circuit. The bike starts and runs. Albeit not very well. ..I'm rebuilding
I have tested as it says in the manual.
Am I missing something here? It says it should be 12k ohms. I'm getting nothing. I'm getting 3 ohms on the primary.

So a few questions:
1. Should I definately be getting 12k ohms between one of the primary wires and the plug cap contact?
2. If they are open howcan the bike run
3. Can any aftermarket coils work with the correct rating?
4 Does any one know of any aftermarket stuff? Upgrades etc

Thanks
Carl

 

NO! There should be no resistance between the primary and seconday side; they are two separate circuits and there should be infinite resistance (i.e. no physical contact between the two circuits).

XJ700 air-cooled models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.7 ohms +/- 10% = 2.43 ohms - 2.97 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
12K ohms +/- 20% = 9,600 ohms - 14,400 ohms acceptable range


Spark plug caps:
1985 N/NC models: 5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range
1986 S/SC models: 10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range


Spark plugs:
1985 N/NC models: 0 ohms per plug
1986 S/SC models: 5K ohms per plug

 

Where do i pin for the 12k ohms please? The end cap contact and earth?

 

primary is pin to pin, secondary is wire to wire (remove cap)

i have the same bike (well 86). upgrade to the dyna coils. (this is a case where the better aftermarket upgrade will be better than an original/oem replacement. an oem replacement is more than the dyna coil, and a used original will have or will soon have the same issues. something is bad in your coil. there should be no contact. period.

 

What do you mean wire to wire?
I have attached the page from the manual. It clearly shows from the pin to the connector. I'm totally confused now.

 

Plug wire to plug wire. #2 wire to #3, and #1 to #4 The plug wires are at opposite ends of the secondary coils.

The service manuals have errors, and that is one of them.

 

So just to try and clear this up. If I put one end of my meter inside no1 plug cap and the other to no 4 plug cap I sound her 12k ohms ??

Did I read the caps have resistors in them or am I just imagining that?

 

no. if you go from plug cap to plug cap you should read 22K ohms
12 k for the coil and 5 k for each spark plug cap they have resistors in them.
spark plug caps unscrew off the wires

Secondary side (spark plug wires, without their end caps):
12K ohms +/- 20% = 9,600 ohms - 14,400 ohms acceptable range

Spark plug caps:
1985 N/NC models: 5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

 

Ah thank you xj550h. Just tested they are all fine so that rules out the coils then

 

have you tested the pickup coils? you do that from the connector on the tci unit.

have you done the valve clearances yet? it is really the first place to start.

are you running with the airbox?
what have you done as far as cleaning the carbs.

 

Valves done. I'll check the pick up.
Yes airbox. Straight rubber boots though.

 

We've been working through some possibilities in a private conversation.
I think at this point it looks like the carbs work was done correctly.
He thinks the rich condition on #2 has been corrected now, but is still having a flat spot at around 3k.
The slides are moving freely, and fuel levels were wet-set on the bench.
Air jets were not removed.
He did a running synch today.
I know people have used straight hose for airbox boots before, but don't recall any negative consequences being reported.
My thought is that a set of proper airbox boots should be sourced and installed just to be sure that it's not the hose causing the flat spot.
A used set will be fine as they rarely crack, and can be re-softened by soaking them in a mix of oil of wintergreen and rubbing alcohol; one part oil to 3 parts alcohol. Soak overnight.

I wanted to bring this back to the collective in case someone has more insight to the problem than I.

 

I did notice the plug spec fitted are slightly hotter them they should be. Someone has put ngk bp6es rather than bp8es as specified by the manual. My unstanding is the 6 denotes a hotter plug.

Remember though it was running fine before i started. Perhaps I'll change them if I can't figure it out.

 

Two heat ranges is more than a little hotter. That could be contributing, and could be causing pre-detonation to occur. Do the insulators have flecks of aluminum on them? Do the ground straps show signs of erosion or melting?

 

Straight rubber boots? What did you use?

Get the right spark plugs. Get a couple seats and do a plug chop. Post the results

2 things I haven't seen mentioned: carb sync and colortune. Have you?

 

I used plumbing tubing with plastic support pipe. Done a carb sync but do not have colortune. 2nd pot is rich. I've leaned it a bit on the mixture screw. I've ordered new boots and got new plugs coming. I may pull the carbs and check fuel float levels again.
Dunno what normally causes a flat spot though

 

Ps What's a "plug chop" by the way?

 

Lack of air-velocity through the carb, which keeps the slides from lifting enough to meet the fuel demand of the engine is one cause.
Thre are many other causes, but I think that is what we are dealing with in your case.

 

A plug chop is performed (in a 4 stroke motor) by running the bike at the road speed that corresponds to the rev-range you need to check the fueling at (mid-range, top-end, etc.) and then hitting the kill-switch to shut the motor off. Pull the plugs (fitting the spares you carried with you) and looking at the color in several places (ground strap, base ring, insulator).
On a 2 stroke engine the insualtor color is really important, so the plug threads actually get chopped off of the plug to expose the insulator).

What you want to see is a grey to tan color on the base ring, and a distinct line of color about halfway up the ground strap. Grey to tan on the insulator is good to see as well, but that takes several hundered miles to develop. ( the classic read is white = very lean, grey = lean but OK, tan = near perfect, various shades of (dry) black = rich).

 

https://www.ngksparkplugs.com/about-ngk/faqs/spark-plug-faqs/how-do-i-read-a-spark-plug

Ps. Do the plug chop on some open road with little traffic. Be safe. You can't start slowing down before you kill the motor. That negates it. Nor do you want someone's bumper up your butt.

Literally, get on some open road, cruise in your flat spot a bit, hit the kill switch, pull in your clutch, and coast to the side of the road.