1988 vmax no fire on both rear cylinders help!?!?!?!?!

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Lance76

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I have a 88 vmax 1200 with 30,000 original Mile's on it been garage kept all her life and ain't been rode since 2011 which I know is hard on one but after a little TLC got her fired up only to realize both my rear cylinders were not fireing so I shut her down on the spot then checked the coils with my meter both showed to be good made a jumper to go from my front coils to my rear and checked and both had fire that way and now I'm stumped so if anyone has got a clue as to what my problem is I'm open to and thankful for any and all suggestions thank you
 

desert_max

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Did your TLC involve carburetor disassembly and cleaning? If not, that would be the place to start. If the carbs are properly sorted and coils have been verified, verification of continuity of the pulsars would be next. I would also unscrew both caps of the plug wires (plug side and coil side) and assess the quality of the copper making contact with those ends. If there's any discoloration or all you see are black holes in the end of the wires, trim back a quarter of an inch and reattach.
 

MaxMidnight

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First step would be to check back over what you did during the t.l.c. session and if nothing found I'd be inclined to start with the pick-up coils..
First break and make connectors from them to the ICU and then check resistance which should be between 94 to 126Ω at 20°C.
 

Fire-medic

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First step would be to check back over what you did during the t.l.c. session and if nothing found I'd be inclined to start with the pick-up coils..
First break and make connectors from them to the ICU and then check resistance which should be between 94 to 126Ω at 20°C.
Since he has the 'early' ignition, he has a 5-wire/two pick-up coil ignition system. I'd check for the connector being not green with corrosion, and that the pins for the rear cyl's (that would be #1 & #3) are properly-seated in the molex nylon connector, that they are tightly-gripping the pins (male/female tightness) as well as the above suggestions.

As I understand it, you ran jumpers from the front coils to the rear cylinders, to see if they sparked? Now do the opposite: from the rear coils to the front cylinders. If they (the front spark plugs) don't spark (remember they need to be grounded to work properly, if they're out of the cyl heads), I'd say you have discovered that your pick-up coil for the rear cylinders has an issue in continuity.

VMax engine cyl numbers 1-4.png
 

Lance76

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Update on this guys and by the way thank you all for your advice but before I had the chance to see these suggestions me and my buddy were working on the max and realized that we were still jumping the silonoid cause the push button only dimmed my headlite when pushed before like battery was dead but it has plenty of charge so upon inspection there was a lot of crude in the forward control houseing took it apart cleaned everything to the best of our ability without tearing the switch's apart and now have fire still to the front two cylinders and bike turns over as it should with the starter button but the rear cylinders only fire at the begining of the push of the starter button and sometimes when it is being let off of like there may be a short in the push button for the starter if that makes any difference in the diagnosis and I am sorry if this is turning into a bunch of annoying rookie questions to y'all but the electrical part is straight up confusing to me and y'all's help is greatly appreciated!!!!! and by the way Happy Thanksgiving to all of you and your family's
 

DreamV4

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Lucky you, rear coils are easy to get to.
Tests:
Primary resistance
Secondary resistance with and w/o cables
+ at primary connection
blinking test light ate primary module connector
 
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