Introduction: How to Add Swingarm Spool Mounts to a Honda F4i
These are instructions for how to add swingarm spool mounting holes to a Honda F4i swingarm. Swingarm spools provide a safer and much more convenient method of lifting the rear of your bike for doing tire changes, chain lube, etc. Most bikes come with threaded mounting holes for spools, but the F4i is an exception (this could also be done on any other bike that doesn't come with spool mounting holes). This definitely isn't the simplest way, but I wanted a nice clean look without the mounting holes sticking off the bottom, and I wanted something stronger than just drilling and tapping a hole in the relatively thin-walled, hollow, aluminum swingarm.
This method requires that you take the swingarm off the bike. I won't go into detail on taking the swingarm off, so if you haven't done that before and you don't know how, you might want to take a look at the service manual or something similar. The swingarm on your bike should look something like the picture above. I also added a picture of some spools on another bike so you can see how they work.
I did all the work at the TechShop in Menlo Park, CA because they have all the tools I needed including an engine hoist, TIG welder, sandblaster, powdercoating system, angle grinder, hand tools, etc. If you're interested in TechShop it's a DIY membership-based workshop, you can get more info at www.techshop.ws
Step 1: Remove Swingarm
As I said I won't go into detail on removing the swingarm, but you'll need to lift the rear of the bike without using the swingarm, which means you can't use a traditional rear stand. I used an engine hoist at the TechShop to hold the back end up, but you could also probably use a jack if you're careful. You'll have to remove the rear tire, the brake caliper and lines, and the front sprocket cover, before you can remove the swingarm. You'll also have to make a special tool that looks like the picture above for the locking collar on the swingarm pivot bolt (marked in red on the second picture). I used an angle grinder with a cut off wheel to cut reliefs in an old socket.
Step 2: Machine Inserts
Now you'll have to machine some threaded aluminum inserts that will slide through both sides of the swingarm and be welded in. I used a manual engine lathe at the TechShop. The thread diameter and pitch will have to match whatever threads your spool mounting bolts have, and the outside diameter of the inserts should be at least twice the nominal thread diameter for strength. The inserts need to be long enough to go through the swingarm and stick out a bit on either side to give you a surface to weld to.
Step 3: Drill/Weld
The next step is to drill holes through the swingarm using a hole saw or oversized drill bit. The holes need to be big enough to fit the inserts snugly, and the holes should be perpendicular to the outer surface of the swingarm. Once you have drilled the holes, clean the metal surrounding them, and weld the inserts in place. I used a TIG welder at the TechShop.
Step 4: Paint/Reinstall
Once everything has cooled down, you can touch up the swingarm with some flat black spray paint and reinstall it. I decided to powdercoat mine instead because they have a sandblaster and a powdercoating system at the TechShop. It came out really nice but I haven't put the bike back together yet so I don't have any pictures of the finished product. With the spools installed, it will look something like the picture above.
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