1976 sportster no spark
#1
1976 sportster no spark
so I picked up a 76 I was told it ran until they moved the coil and changed out gas tank and put a new battery on they were jumping it with out a battery coil has power to it but nothing to the sparkplug wires and ohms are 0.35 to the + and- and nothing form the + to the sparkplug with and no volts to the plugs wires at all and the bike does not have a kill switch or start button it just has the wires where should I start does it sound like I need a new coil? thanks
#2
You will need to gete these two Factory manuals ...
99484-78 Service Manual
99451-78B Parts Catalog
Search eBay and Google for the part numbers.
There are ohms tests in the FSM, but they are not definitive. If they come out right the coil may still be bad. The only true test is to install a known good one and see if the problem goes away. If you buy a new one and discover the old one is good it is not a waste of $s. A good spare coil is like any other good, useful tool to have in your shop.
The ohms tests are done between the two primary terminals [electrical] and between the two secondary [spark plug wire] terminals - with all wires etc disconnected. Should be 4.7 to 5.7 ohms primary and about 16000 to 20000 secondary.
The tests that you did are not correct; i do not know if they would have caused any damage.
One side of the coil has a white wire that originates with the RUN switch. That terminal should have 12 volts. The other terminal has a wire from the ignition module/points - it carries a signal not a voltage.
Please put some punctuation in your posts.
Welcome! to wrenching on an IronHead - that has been messed with by how many previous owners [POs]. This will be a journey. Hope we can help you along.
99484-78 Service Manual
99451-78B Parts Catalog
Search eBay and Google for the part numbers.
There are ohms tests in the FSM, but they are not definitive. If they come out right the coil may still be bad. The only true test is to install a known good one and see if the problem goes away. If you buy a new one and discover the old one is good it is not a waste of $s. A good spare coil is like any other good, useful tool to have in your shop.
The ohms tests are done between the two primary terminals [electrical] and between the two secondary [spark plug wire] terminals - with all wires etc disconnected. Should be 4.7 to 5.7 ohms primary and about 16000 to 20000 secondary.
The tests that you did are not correct; i do not know if they would have caused any damage.
One side of the coil has a white wire that originates with the RUN switch. That terminal should have 12 volts. The other terminal has a wire from the ignition module/points - it carries a signal not a voltage.
Please put some punctuation in your posts.
Welcome! to wrenching on an IronHead - that has been messed with by how many previous owners [POs]. This will be a journey. Hope we can help you along.
#5
Join Date: Jan 2011
Location: Southeast Michigan 15 Minutes East Of Hell
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Power to coil ... is there power coming out of the coil ... pulses? ... Have you checked the points, breaker plate, and don't forget the advance mechanism ... It can ( and usually does freeze ) this wont cause loss of spark but will definitely make it hard to start
#6
Take a day or two and work thru all three of these threads; you'll be glad that you did
Ironhead Charging System Checkout
http://xlforum.net/vbportal/forums/s...ad.php?t=39146
Start System Testing
http://xlforum.net/vbportal/forums/s....php?t=1610248
Ironhead Voltage Drop Testing
http://xlforum.net/vbportal/forums/s....php?t=1608465
Ironhead Charging System Checkout
http://xlforum.net/vbportal/forums/s...ad.php?t=39146
Start System Testing
http://xlforum.net/vbportal/forums/s....php?t=1610248
Ironhead Voltage Drop Testing
http://xlforum.net/vbportal/forums/s....php?t=1608465
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