easiest way to get to the coils

82 Maxim. I am fighting the dreaded no spark issue. I need to see if I have voltage to the coils, but them babies are buried. Any thoughts, tips, or hints would be appreciated. As a side note, I bought the bike non running, carbs were crap. Fully rebuilt now, and now no spark.

I'm actually dealing with the same issue with a '78. On the '78 the coils are mounted on the frame underneath the tank. I ohm'd out my coils and they seems to check out okay (I think). Manual shows how to test. The primary was 4 ohms and the secondary was about 18K ohms. I'm assuming that is okay. You will want to test out the coils, but also the condenser could be bad. I'm thinking my condenser is bad. From what I read, the condenser is just a capacitor. Capacitors are notorious for drying up over time. My bike had been sitting for 26 years, so I wouldn't be surprised in the least if the condenser is bad.

I tested the capacitance of my condenser using my meter and it gave me readings of about 243uF instead of 0.26uF as indicated on the condenser plate. I'm assuming that is bad. What I'm not sure of is whether or not a bad condenser will keep you from getting spark.

Well, I know I'm not helping you any. But, I'm learning something in the process and maybe passing this info along could help someone later on.

My issue has been 'no spark on left side'. I have my condenser removed and I still get a spark on the right side (although seems kinda weak). So, I guess the condenser does not affect the spark to the plug. So, I don't think a bad condenser would cause a no spark condition (maybe someone will correct me if I'm wrong).

I'm still trying to figure out how to get to them. Tanks off, but they are buried and I don't know how to get to them.

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Mine (on the '78) are easy to see and get to after removing the tank. Not sure about your particular model. Here's a thread which may help.

http://www.xs400.com/forum/showthread.php?t=8643

http://www.xs400.com/forum/showthread.php?t=11272

or
http://www.lmgtfy.com/?q=maxim+tank+removal

I didn't preview further, I am sure your answer is listed in both places. (82 coil access) (with focus on the tank removal)

Alright, coils are fine, 3 ohm. Pulled side cover off to check the pick ups. Old nasty fuel ran all over my garage floor. 1st, how do I check the pick ups, and 2nd, I'm glad I didn't get this thing running.

Pickups test in the proper range. Good thing for the +/- 10%. So I am assuming my ignitor is bad.

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Hmm, a new no-spark, first cheapest fix, is to take off the wires from both the coil, and the plug. Cut off 1/2 inch (10 mm) of wire, from Both sides. My theory is that one or both sides, have been tarnished to the point of it no longer works. (unsubstantiated) By cutting out the 1/2 inch, you will put the spike/screw into new fresh wire.

(get new plugs/wire/caps. last time I got them from my local yamaha guy, for just over 10bucks. (2 plugs, (listed in my signature) 2 to 3 feet of wire. and I would suggest the NGK 5k resistor caps. if you can't find just get what you can.

Then if you still suspect no spark, be carefull of testining with out the spark plug in, the manaul clearly warns that you can destroy your TCI.

One weird thing I did notice was that with key on, the was 10.5 volts on my meter with the positive in the plug boot and the other side grounded.

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Here`s my post on testing the pickup coils.

http://www.xs400.com/forum/showthread.php?t=10824

imo - one of these will most likely go before the TDI or coils