82 xs400j testing pickup coil's & intro

[filterx]

hey...

Firstly, new here & I've been following this forum for the last few weeks so most of you have seen before - neighbour gave me a 82 xs400j which hadn't been plated since 1992 etc, etc etc.

I'm fairly mechanically inclined and fortunately have a patient Yamaha dealer in my town. I'm an avid dirt biker (1986 Honda reflex & 2005 Honda crf250r) and do most maintenance myself

I've down loaded all the manuals, and have followed everyone's excellent advise for most of the issues I've run into so thanks in advance for this..

OK - right off checked for spark and noticed nothing on the right side and OK on the left. put in new plug's same so put this on the back burner for a bit.

Started my electrical check from the fuse block which was toast so replaced and rewired. Then started on ALL connection's which I've cleaned, tested (fixed if needed) and dielectric greased

Back to the ignition/spark issue (I did a forum wide search and could not find an answer for this)

Pulled the coil's/plug wire's (tested cleaned etc) then swapped over wiring and confirmed that I could then get spark on RIGHT and nothing on the LEFT which pointed me to the pickup coil's.

1) I've pulled the whole pickup coil wiring harness out and stripped off all the casing from the rubber grommet back to the connector to confirm there's no visual break's and to expose the connections just past the grommet

2) My Yamaha dealer was a bit vague about this so what I did to test is to set my meter to ohms x1k to test for continuity and tested as follows'
a) BLACK to BIEGE - YES continuity
b) BLACK to ORANGE - NO continuity

3) Does this confirm that the BLACK to ORANGE pickup coil is bad and if not is there another test???????

If this is correct and one of the pickup coils is bad I'll be in the market for a working used set since my dealer is telling me they are NLA. (there are some on ebay if I have to go this way) but I'd rather buy from someone here

thanks
filter

err this should have gone in to the electrical section

 

[Charles]

I guess it's a bot too late, but did you try swapping just the plug wires and boots? A lot of times it's a bad boot/wire.

 

[filterx]

I guess it's a bot too late, but did you try swapping just the plug wires and boots? A lot of times it's a bad boot/wire.

hey man..

easy enough to put the pickup's back in so never to late but....

if i'm getting a strong spark on the left and nothing on the right, by pulling the coil's and swapping just the connection then getting a strong spark on the right and nothing on the left, I assumed this would eliminate most issues with the coil's, spark wire/cap's, & spark plug's although I've been called stupid more than once

tia
filterx

 

[Charles]

Perhaps I misunderstood. I assumed you swapped the wires, boots AND the coils all at once. If so, then you won't know if the wire of the boot was the culprit. Basically, I swap plugs first, then plug wires/boots, then coils. That usually pinpoints the issue.

 

[16VGTIDave]

Sounds like you've done all the right testing Filterx. I'd go over the wiring once more to see if it is a broken wire before you order another set of pick-ups.

 

[XSLeo]

I'm not sure on your pickups but on the XS650 there is a spec for the amount of ohms for the pick ups. The XS650 uses two pickups in one unit. They have a common ground with two hots.
Test the ohms from each hot to the common ground. 80-81 the spec is 550-850 ohms. The 82 up speced at 630-770 ohms.
I don't know if this helps but it seems your repair manual should have a spec for the pickups.
Leo

 

[salbuca]

Hey there im new to the fourm but I seem to be having the same problem on my 82 xs 400 maxim...spark on left side none on right or intermittent on right side. this is driving me crazy ive had the bike striped multiple times trying to find something, my readings for the field coil is 7.7 ohms which is a lot higher then the book says could that be the problem? also my ignition coils read 3.3 ohms when I did the primary test.. the book says it should be 2.75 am I to far out of range are the coils bad?

also this is my first project picked her up not running changed plugs got it going only to find the misfire and it dies then wont start again. ive read a couple posts that seem to have the same problem but there was no resolution on either of the posts I could find.

Any help would be greatly appreciated I am getting very frustrated and borderline wanting to call it quits and cut my losses make it look pretty and sell it off.

cheers
SB

 

[XSLeo]

On the 7.7 ohm feild coil, It will work but the alternator output will be low. It won't charge the battery fully. The TCI can be very voltage sensitive. The low battery voltage causes lots of ignition troubles.
On most electricalpecs therfe is a tolerance, usually 10%. 2.75 + 10% = 3.025. Your coils may or may not be the problem. I might try a different set if I had them.
I would check the battery, if the voltage is low, recharge it with a charger. Once charged, start the bike and check the battery voltage at idle and 2500 rpms and 5000 rpms. Report back with the voltages.
Leo

 

[salbuca]

Hey there it's been a while I got the bike running for a while with a new set of pickup coils...it ran solid for a couple months then it lost spark again ... What I've noticed is when I crank the bike ovr the battery voltage drops to about 11.4 even after a trickle charger over night with full battery charge it still drops .... Am I looking at a grounding issue or is my stator coil/ generator be causing the lack of spark? I've gone through all the other checks and when I turn the key from on to off there is a spark so I don't think there's issue with the coils or wires bit I'm not sure if this is normal for this to happen...thanks for the previous response maybe you could give some insite to this issue ?


Cheers
Sb

 

[16VGTIDave]

If you are getting a spark when you switch OFF the ignition switch or kill switch, then I'm going to guess that your TCI module is shot. The TCI module is supposed to power down the coils if there hasn't been an ignition event in about 10 seconds, to prevent the coils from over heating. This isn't happening with yours, and that is why you are getting a spark when you turn it off. I had the same symptoms when my TCI module went bad.

 

[salbuca]

I have two boxes and I know one used to work I'm mot sure if maybe the cold is affecting it bit when I bypassed my kill switch the bike ran untill I turned it off then no spark again... Is this a symptom of a dieing box or maybe wet contacts ? It does dip to around 5 degrees at night in the garage... would moisture in the box be a factor with it ? If not is there a way to test the tci unit to see if it's actually out of commission? Thanks again

 

[16VGTIDave]

It could be bad solder joints in the TCI module. Or moisture. Or failing 30+ year old components. The testing procedure is in the manual, and it is fairly simple.

 

[salbuca]

Awesome thanks for the reply picked up a new box It worked well for 3 days then the rain came had it parked for 3 days and now I have the same problem .... Would the moisture be destroying tci boxes or would over charging be destroying it ? also are there any after market style of tci's or an upgrade available?

 

[16VGTIDave]

The TCI modules are supposed to be weather proof - when they were made 30+ years ago. Have you tried taking it inside and placing it on a heat register, baseboard heater, radiator, or what ever you heat your home with for a day or 2? Removing the cover would allow any moisture to escape faster.

Electronics are sensitive to voltage. Too high, or too low, a voltage will cause components to fail.

 

[Scorpio1963]

5* at night

 

[xschris]

That's what happens up north.