December 12, 2025
Description
This adapts the original shadow 600 air filter housing to fit a Harley-Davidson FLHTC Electra Glide Classic 1999-2001 (EFI) screamin eagle filter cover!
You will have to replace the stock cover bolt with an M6x30mm one + a washer.
This modification leaves the stock airbox, thus not requiring any carb changes!
The cover also slightly alters the intake noise to be a bit more hollow and grunty which I like.
The orange part was printed to better show the part on the bike in photos.
The black part in later photos was the actual end result.
Reference files
Along with the step file for the main adapter I have also included step files for both the original airbox reference as well as the adapter ring for just the HD cover.
Feel free to use these for adapting other filters and the HD to other bikes!
Print settings:
I would highly recommend choosing a high temperature resistant filament to print these parts out of.
It should also be UV stable for longevity reasons, as well as gasoline resistant just in case.
I printed the part with 6 walls and quite a bit of gyroid infill + extra top and bottom layers just in case.
Don't forget to enable supports!
Assembly:
Remove the stock cover and place the adapter where the stock cover would normally go.
Place the spacer into the HD air filter with the smaller side (with the nub) facing the HD cover and the thicker side facing the engine side.
Place the bolt with washer through the cover and through the spacer, the nub sits in the HD cover hole to adapt the bigger hole to M6.
Place the HD cover onto the adapter making sure it's fully seated all the way around.
Tighten down the bolt and done!
Disclaimer:
Use this part is at your own risk.
License:
Creative Commons — Attribution — Share Alike
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