Ignition Coil problem? Maybe battery?

I have a XJ700X (maxim X).

My bike has been intermittently running on 2 or 3 cylinders the past few days, and is a real dog to start.

1st - this battery sat DRY for 5 years - and I have been using it to run the bike for the past week. Amazing, huh! Obviously, it is crapping out on me because it is hard to get started, and the starter is grinding like crazy. My question is, could having a bad battery make the thing run like crap once it is started? Specifically - can it make some of the ignition screw up so bad that not all cylinders are firing?

2nd - I tested the resistance of my coils. This one really has me confused. The primary side tested okay (I measured the resistance between the two small wires inputting to a single coil, and I did this for both coils.) BUT - the manual said to test the secondary side, I should measure the resistance between the spark plug cap and the red and white input wire to the coil! For this reading on both coils I got infinite resistance, which means no connection. However, I know I am getting some spark because I pulled out the plugs and watched. (I think the manual is wrong)

My brother's XJ650 (different bike) manual says to test the secondary resistance between spark plug caps 1 and 4. When I test this resistance, I get 34 KiloOhms on both coils. The secondary resistance that the manual gives me (mind you - with the method I talked about above, not this one) is 12 KiloOhm. When I look at my electrical schematic, it shows the secondary coil to run between two spark plugs.

What does all of this mean? Can my coils be the problem? I did not test the Pickup Coil Resistance, but I assumed since I was getting some spark in all of my cylinders, that this would not be a problem.

So - are my coils the problem? Is my battery the problem? I am thinking it is definetely electric, because right before I washed my bike (I am kicking myself for wanting it to look good), everything was working. And I am assuming that carb problems don't drastically change so that two carbs go out at once, and then one comes back, and then the bike won't start up.

Also - will the sidestand relay allow the bike to turn over but not fire? I don't think this is true.

Thanks for listening to my rambling. You guys are awesome.

 

I also forgot to mention another symptom. When it was idling just prior to its painful demise, the tach would go down to zero, and then jump back up... Is this indicative of not getting spark in a certain cylinder? What does this mean?

 

Hmmm... I may just solve this one yet... It appears that I was supposed to pull the plug caps off when measuring resistance. But that should have just added 10KOhm - not 20.

So it still might be the coils.

But I suspect the battery. I have a new one charging in the garage. I will let you guys know tomorrow.

 

But I could just keep talking to myself, kinda fun! Or maybe I am crazy...

Electrical stuff tends to make me crazy. Bad carbs - no problem. Electrical gremlins tend to ruin my day.

 

A bad battery could definately cause you some ignition headaches. A battery not only stores a charge for starting purposes but also acts as a buffer to help regulate over all system voltage. If you have system voltage spikes and valleys due to a subpar battery it could be causing your coils to act up, resulting in engine misfire, sputtering and surging.

Let us know how it runs with a fresh battery.

 

Hey richard03, sorry I don't have info on the Maxim X.

The Yamaha XJ650/750 manual shows a picture of testing the coil between the two high tension leads with the plug caps on. I didn't see any documentation of taking the caps off or leaving them on!

Pick up coil resitance 650 ohms +- 20% at 68 degrees F. (for the XJ750)
700 ohms +- 20% at 68 degrees F. (for the XJ650)

Spark plug cap resistance 5k ohms for No. 1 & No. 4
10k ohms for No. 2 & No. 3

Primary coil resistance 2.5 ohms +/- 10% at 68 degrees F.

Secondary coil resistance 11K ohms +/- 20% at 68 degrees F.

Troubleshootings suggests:
1. check entire ignition for poor connections
2. check battery for low voltage and specific gravity
3. check fuses for weak connection or open circuit
4. check resistance of ignition coil primary and secondary
5. check pickup coil resistance
6. if all of above check out okay - final conclusion is faulty TCI

If all was fine until you washed it, I would be checking the connections for corrosion, dampness, shorting out, also look into the TCI for possible water/moisture intrusion. Maybe put a hair dryer on it for a bit?

 

Thanks... will do. I will be putting a fresh battery in it right now!

 

Your battery is part of the problem. Your coils should show something on the secondary resistance reading (not infinity) as you experienced with your brothers coils. I expect that the secondary lines on your coils are corroded and should be replaced. Even with the caps in place, you should be able to see resistance, albeit slightly higher (usually 5K more resistance built into the cap) than normal. Looking forward to hearing your problem is fixed.

 

Well, I was getting a reading between the caps on cylinders 1&4 and 2&3. I wasn't getting a reading between the primary coil and secondary, which is what the manual said to check. Personally, I think the manual is wrong. I would rather have infinite resistance between the primary and secondary coils.

On to the good news... The bike runs now! I put in the new battery, and once I got the carbs synced again, it runs better than before!

Also - I was able to get the brass caps off of my idle mixture screws without damaging the screws.

I am having a good day!

Thanks for the help guys!

 

Another lesson to learn about batteries. IF left in a discharged state too long sulfation will occur. This appears as white crystaline deposits on the lead plates. Once this happens the battery will never go back to full strength. It can also occur if the battery is not well maintained leaving the plates exposed due to low fluid level. So check your batteries once a month and replenish with distilled water. I just rescued a buddy on the roadside when his bike quit due to a bad battery. Pulled it and the fluid level was at the bottom of the plates. New battery time!
On the other side, a local hog rider has kept meticulious care of his battery and it has served his Harley well since he bought the bike new. He bought the bike in 1999. Yep...seven years on ONE battery!

 

You gotta be kidding me! Seven years? I'm a good boy and have never seen anything beyond 3 years. I gotta get educated on this, I'm changing batteries every spring even with a floating charger and regular checks on the acid level. Grrr.... of course none of my batteries are standard save the Max and run $50 plus everytime. I simply accept it as operating costs.

 

I am dead serious! Only guy I know that has had one last this long. Best I ever got was 4 years. This is an Army Colonel in charge of a research base here in town. He wouldn't lie. I even accused him of that when he first told me. After getting to know him I now trust him implicitly. Seven years and he bought the bike in Alaska. Maybe they sell heartier batteries there!

 

Might well be. I've read that there is not a single trickle charger in existance that will keep your battery in top shape over the winter season and that only good old fashioned TLC (ie regular checkups every two weeks) is the only way to ensure a live battery come spring. Sigh, I guess I keep hoping, I am fairly lazy.