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Steve
Steve, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 6844
Experience:  30+ yrs. experience, MMI, HD technician, HD early, engine rebuild/performance, bike builder, kit bike program manager, CCI 2001-2004
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2006 sportster 1200xl rear cylinder not firing been to dealer

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2006 sportster 1200xl rear cylinder not firing been to dealer twice and both times they said it had a fouled plug. I rode home from dealer about 40 miles and it was fine now same problem. I have changed the plugs, I took off coil and ohmed it out and it falls within range in clymer manual, any ideas?

Hi bansheenut,

what ohm readings did you get?

does your coil have 2 or 3 primary terminals?

Steve

Customer: replied 6 years ago.

Steve,

I have the coil here now, it has a plug on top with 3 teminals and primary readings are 0.8 and secondary readings are 5.8

Bansheenut,

do me a favor......with your ohmmeter on the RX1 scale, measure the resistance of each primary winding from the center pin to each outboard pin and tell what they both read. then, measure across the secondary winding (spark plug wire terminals) on the RX100 scale and tell me what that reads.

then I want you to take a real good look at the connectors for the primary coil connector and look for distorted, damaged or dirty/corroded connections on the coil and the primary coil connector on the bike.

tell me what you see.

Steve

Customer: replied 6 years ago.

Steve,

 

I may not have the correct meter my scales are 200 and 200k. The primary reading is on 200 setting and it reads 0.8 and secondary setting is 200k and it now reads 6.1 maybe because coil is warm from being inside house? Also the meter is digital. The connectors on both coil and the bike look clean with no damage.

Thanks

bansheenut

Banshee,

your meter is fine. your primary resistance should be 0.5 ohm. 0.8 on a 200 ohm scale is close enough. was that 0.8 from center pin to front and to rear terminal????

your primary resistance should be around 10 k. your reading is 6.1k which is a little low, but I would go there just yet.

the problem with troubleshooting a single fire ignition is, your problem could be just a spark plug (you've eliminated that), just a plug wire, your coil or your ignition module.

so.......inspect both ends of both plug wires and tell me if you see any difference.

Steve

Customer: replied 6 years ago.

Steve,

 

Yes that 0.8 is from center pin to front and rear. I also have both spark plug wires in here also and they both have a reading of 7.0 on the 200k scale. I also tried changing the wires from coil to plug to see if I could move the misfire to the front cylinder but the back one still misfired. So I think the wires are good?

Banshee,

I agree.

if your coil connector plug and contacts are good, this indicates a problem with the ignition module.

there can be things on your bike causing a problem with the ignition module, so we'll need to check those.

what is the voltage across the battery terminals with the engine running at about 2,000 rpm???

check that both ends of both battery cables are clean and tight.

Steve

Customer: replied 6 years ago.

Steve,

The bike doesn't have a tach, but revving it some the voltage is 14.21?

 

Thanks,

Bansheenut

banshee,

your charging voltage is excellent. your charging system is good to go.

check the battery cables and check terminations on your circuit breakers, under the your left side cover. the ignition breaker is the one with a gray wire on it. make sure all the connections are clean and tight.

if this all checks out, do a compression check on both cylinders. if you need help with that, let me know and I can lead you through it.

if you don't have one, you can buy a compression tester with 12mm adapter from Sears fairly cheap.

Steve



Edited by steve on 2/25/2010 at 2:32 AM EST
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Customer: replied 6 years ago.

Steve,

 

I think we got it, I took out all the fuses under left side cover and the were all good, but I sanded them off anyway, but while I was doing this, I put the space heater near the ignition module and heated it up. After I put the fuses back and started it the back cylinder started firing!!! Woo Hoo, sometimes its nice to talk with somebody just to be sure I'm on the right track. Thank you so much and have a good night!

 

Thanks Again,

Bansheenut