RXB Drill Through Rear Subframe "Mod"

zero_dgz · 09-18-2022, 06:36 PM

Well, as predicted. This finally happened.

I went messing around with my luggage on the RXB250L today and wound up having to remove the seat. When I put it all back together one of the seat bolts wouldn't thread in anymore. The threads were just completely pulled out of the hole in the frame. I saw this coming a while back, so I sprung into action with my master plan.

Step 1: Drill a hole clean through both sides so you can see daylight right through it.

Step 2: Find a nice long piece of all-thread.

Step 3: ???

Step 4: Profit.

The stock design of the seat bolts on the current RXB really leaves a lot to be desired and is very failure prone. There are two long and soft 6mm bolts that thread through the luggage rack, a 1" long or so spacer, the rear side plastic panel, a tab in the bottom of the seat pan, the inner plastic of the rear fender panel, and then into a shoddily machined threaded insert that's welded to the inside of the frame tube. That means that the bolt needs to pass through five things that all need to line up perfectly and due to the usual Chinese manufacturing tolerances, none of the holes actually line up properly so every time you're flexing and bending and jiggling everything until the bolt goes home and you'd better hope you don't cross-thread it. Then, the entire load of whatever is on your luggage rack is transmitted directly to the cheese soft threads in the bolt holes, and the luggage rack arms are slightly wider than they should be so the entire ensemble is slightly spring loaded.

To solve the line-up problems, I put all the plastics and seat pan and so forth in place and then just drilled a slightly larger 7mm or so hole through the entire sandwich so there's a new hole through everything now that lines up perfectly. However, the threaded holes are also not quite in the same position as each other on the left side of the frame vs. the right so I had to oval out the holes in the frame a little bit to make everything work. To assist in reassembly (these are bolts you have to take out a lot -- every time you need to access the battery or air filter, or remove the tank) I put a pilot tip on my redneck custom all-thread bolt.

If you don't want to annoy yourself doing this, I suggest ordering a piece of stainless 6mm all-thread from the internet. 1/4-20" all-thread that's commonly available from American hardware stores will work, but then you'll have exactly one fractional inch fastener on the entire bike you'll have to remember to carry around a different wrench for.

09-18-2022, 06:36 PM	#1
zero_dgz Join Date: Jan 2020 Posts: 257	RXB Drill Through Rear Subframe "Mod" Well, as predicted. This finally happened. I went messing around with my luggage on the RXB250L today and wound up having to remove the seat. When I put it all back together one of the seat bolts wouldn't thread in anymore. The threads were just completely pulled out of the hole in the frame. I saw this coming a while back, so I sprung into action with my master plan. Step 1: Drill a hole clean through both sides so you can see daylight right through it. Step 2: Find a nice long piece of all-thread. Step 3: ??? Step 4: Profit. The stock design of the seat bolts on the current RXB really leaves a lot to be desired and is very failure prone. There are two long and soft 6mm bolts that thread through the luggage rack, a 1" long or so spacer, the rear side plastic panel, a tab in the bottom of the seat pan, the inner plastic of the rear fender panel, and then into a shoddily machined threaded insert that's welded to the inside of the frame tube. That means that the bolt needs to pass through five things that all need to line up perfectly and due to the usual Chinese manufacturing tolerances, none of the holes actually line up properly so every time you're flexing and bending and jiggling everything until the bolt goes home and you'd better hope you don't cross-thread it. Then, the entire load of whatever is on your luggage rack is transmitted directly to the cheese soft threads in the bolt holes, and the luggage rack arms are slightly wider than they should be so the entire ensemble is slightly spring loaded. To solve the line-up problems, I put all the plastics and seat pan and so forth in place and then just drilled a slightly larger 7mm or so hole through the entire sandwich so there's a new hole through everything now that lines up perfectly. However, the threaded holes are also not quite in the same position as each other on the left side of the frame vs. the right so I had to oval out the holes in the frame a little bit to make everything work. To assist in reassembly (these are bolts you have to take out a lot -- every time you need to access the battery or air filter, or remove the tank) I put a pilot tip on my redneck custom all-thread bolt. If you don't want to annoy yourself doing this, I suggest ordering a piece of stainless 6mm all-thread from the internet. 1/4-20" all-thread that's commonly available from American hardware stores will work, but then you'll have exactly one fractional inch fastener on the entire bike you'll have to remember to carry around a different wrench for.
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