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pick up coil query

Started by fjman, December 25, 2010, 07:07:12 PM

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fjman

How does the wiring go from the pick up coil to the cdi? I understand that there are 3 wires. (black, orange, gray). I can't tell exactly where the wires should be just by looking at the diagram. It's a 1984 yamaha fj1100.
I made a previous post already. It sparks but somehow the engine hesitates to start. groundings are fine. strong battery. starter spins fast.





andyb

If it's getting spark, describe/define that.  Fat spark, or wimpy little orange glow?

Do you get any sound of firing at all?  Misfires, farting through the carbs or pipe?

Did the bike run before anything major has been done?  After reading your other posts a bit, it sounds like you've been quite deep into this motor.  Good job!  That being said:

If you've got fuel, you'll know it.  Crank it for a bit with the throttle off and the choke full-on, pull a plug.  Smells like fuel, yes?
If you're getting any spark, you should be getting at least some noise from the motor trying to snap, crackle, and pop.

Because of your recent service, I'd be inclined to make absolutely sure that you don't have the cams 180 out. 

Past that, standard troubleshooting should see you through.  It's possible that you're firing the coils backwards (1-4 lighting when 2-3 should and v/v).  You could also have a crap connection (high resistance) somewhere that is allowing only a very weak spark that is blown out, so to speak, by the cylinder's pressure.  Dirty plugs, wrong gap, buggered HT leads, blah blah blah, lots of simple stuff that I'm skipping here. 

Back to the basics then.  Spark, fuel, compression.  Fuel's easy and it sounds like you're making sparks, cam timing can be an interesting one.  If the starter spins the motor over quite easily, is it possibly not building compression properly and thus giving the starter an easier job?

Appears to be a UK model bike (judging by the speedo?), so the TCI  needs to see the black wire as a ground.  The orange and grey appear to flash a momentary change in resistance (spec is 149-182ohms) to trigger the TCI lighting things.  It doesn't seem to me that it should matter if they were reversed (O + Gr), and if you're getting spark, you're getting spark.  Without doing some intentional grinding/drilling/hacking it shouldn't be possible to get the ignition timing too far out of whack, so we can assume that the spark is happening at appropriate times (if it's firing the correct coil off, as mentioned above). 

I've got the CDI version, or I'd go see what the pinout should be.  Sorry about that.





andyb

If it was mine, honestly I'd look for continuity between 1+3 and 2+4 on your TCI because that would indicate ground.  Course, it could start armageddon, also.

At a guess (usual disclaimers apply) and some digging for internet pictures, my money is going to go onto:  orange and grey on 1+3.  Apparently the FJ TCI is interchangable (well, physically, but the curves aren't right) on things like the XS1100, and I found a clear picture of one.

Appears that yamaha used the same PCB for most of the TCI's in that era, so it'd make sense that they'd have kept the pinouts the same and save money on assembly and wiring, though the settings that alter curves are different, and some had a vacuum triggered advance.

racerrad8

I just check the P/U from my bike and it is:

#2 - Black
#1 - Orange
#3 - Grey

Randy - RPM
Randy - RPM

fjman

thanks for the help. I'll look into it asap. A bit busy with the holidays. I've installed the cams by following the markers on the bearing caps. I saw one thread about cams here in the site. I get an occasional backfire in the pipes. The bike was running before the rebuild. I'm getting some noise from the engine like a snap,pop its trying to start. If I remove the plugs its wet with fuel.