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What's The Correct Autolite Gap?


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Please help me give the best care to my poor old 2000 R1100RT. From the archives, I've found the gap for Autolite #3923 plug to be one of these, and I don't know which one to use:






Getting psyched on trying to do my first service.


Thanks in Advance,




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Dan, the spec is .031” to .039”.. With .039” being the upper wear limit.. The larger the gap within reason the larger the spark across the gap.. There is a limit due to coil capability& ign wiring insulation.. Practically around .040”-.045” or so..


If you set the gap to .039” you will have to replace the plugs very very often.. If you set the gap to .031” you are giving up some spark intensity..


So .035” is a good compromise..




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Good words from Twisty as usual. What is your recommendation for changing wires? Any opinion on OEM vs. the beemerboneyard replacements?


For Boone60, the previous owner of my RT had obviously ignored his 3923 plugs cuz when I pulled them they were toast. I got the BMW plugs and the surging was not bad but it was there. Then I replaced with 3923s to great success.


One weird thing that happened to me is that I gapped both plugs and installed. Went for a ride and it was running like crap. I pulled the plugs to discover the electrode from one was way way bent. Like I had dropped it but I swear I didn't??? Would a voltage spike do this? I regapped and runs like buttah.

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