Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: guest381 on November 18, 2009, 03:14:13 PM
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Been having a few problems (a whole raft of 'em really) been going through the ignition system as the spark is puny. Ignition coil is out of spec slightly 10 ohms (secondary winding is supposed to be 5-7 ohms). But the magneto coil is a country mile out, pick up coil is right in spec but the source coil is 220 ohms when it's suppose to be between 84-156 ohms. Tried the spare magneto I had laying about but it had similar resistance. Is this normal? Any other problems that could cause a weak spark? (I've fitted new plug and ignition coil)
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the figured I have are
Ignition coil primary 0.48 to 0.72 ohms @ 68f
secondary 5.2K to 7.8K ohms @ 68f
source coil (brown & red wires) 84 to 156 ohms @ 68f
pickup coil between white/green and green wires
and white/red and green wires
(this is a center tap coil, green being the center wire)
92 to 138 ohms @ 68f
I assume you mean 10K ohms for your ignition coil secondary? not 10 ohms.
I wouldn't think the 220 ohms you are seeing on the source coil is indicative of a problem if it means there are a few more windings causing the higher resistance, as more windings mean more induced current, if however it's due to a bad joint or corrosion somewhere in the windings then it may be a problem....it's ages since i measured mine.....might have a look this weekend.....oh...and your meter may not be too accurate? unless of course you have a good old avo or similar.
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Yep sorry ment 10k. The contacts on both source coils have clean contacts, but I cant see that both coils had the same fault at very similar values resistance (only 8 ohms difference)? Am I just unlucky?
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either the center tap has a high resistance joint somewhere between the connector and the point it meets the winding....or it's ok