Aftermarket Ignition Coils

Hello all,

Still trying to figure out how to work a forum and all so thanks for your patience. I have been trying to revive an 82 XJ650 Maxim. I am currently at the point where I can get it to crank though I am pretty sure I have no spark. I am starting to wonder if there is an issue with the coils. Does anyone have any recommendations on new ignition coils that wont break the bank? I appreciate all the help. Just a note.. I am also not a mechanic lol.

 

First of all check the battery under load. On the XJ bikes there can be enough power from the battery to crank the engine but not operate the transistors in your TCI. If the transistors don't work there will be no sparks at the plugs. You should have at least a 10 volt reading on the multimeter when cranking the engine.

 

Honda 750 cois are priced low.
but before you start buying things you do not need you will want to do a few tests.

1st battery voltage drop test record battery sitting voltage then battery voltage drop when cranking. must be 10 volts or better during test

Ohm out the ignition coils primary wires and secondary wires
ohm out pickup coils

you may want to replace the ignition fuse with an inline blade fuse holder
with the intention of replacing the whole fuse box at some point.


when doing secondarys you can leave caps on for initial test just add the 2 caps value to expected readings.
many times the plug wire gets corroded and needs to be trimed back a little after you remove cap.

this post wil have specs fo ignnition and charging system and many other things

The Ultimate Relay, Switch, Sensor, and Diodes Guide

XJ650 models:

Pick-up coils
1982-84 XJ650 Maxim: 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982 XJ650RJC Seca (yics engine): 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range

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

Spark plugs:
0 ohms per plug

 

well people, it sure seems I should get myself a multimeter and educate myself on how it works. I appreciate all them help. I will follow up with my findings.

 

There is a thread on the site explaining how to use a multimeter someone will know where it is.

 

Read This First

How to Use a Multimeter and Read Schematics and Wiring Diagrams.

 

I got a set of coils off ebay that were advertised as compatable with an xj750. they were cheap so I figured I'd take a risk.
they ohm out at 5 ohms primary and 15k ohms secondary. would this combination of resistance blow the TCI on my 81 xj750 Seca ?
I measured the ohms with the caps off. They came with their own caps. If the caps have no resistance, does this make a difference ?

 

Will the CB750 coils work on xj650 maxim and seca?
the Chinese coils, described as compatible with xj750s, were terrible. The bike ran rough and the the control display did flip flops.
They OHMed at 5 ohms primary and 15k OHMs secondary with "0"k caps. Yes coils that are too high in resistance mess with the TCI