The F2 (Frankenchopper v2.0) – ’11 Suzuki GSXF1250 Chop

This bike is also being put together out of spare parts, mostly obtained from dismantlers and Ebay.

It promises to be an adventure getting it retitled in FL as an ‘assembled from parts’ bike once it’s put together…


Mods will include a 4.125" extension of the swingarm, 6.5" fork stretch, rake adjustment to 40 degrees, and bobbing the rear.

Factory engine and electronics are really reliable, so I’m going to keep them.

For those of you who like numbers:

Wheelbase will go from factory 54” to 72”

Rake will go from factory 25.3 degrees to 40 degrees

True Trail will go from factory 2.8” to 6.35”.  We’ll see if I have to add a steering damper to minimize low-speed flop.



Here's the frame and I'm starting with (got it on eBay)

Here’s the engine, also eBay.  Less than 10k miles.



Here’s some concept sketches showing swingarm/rake/fork mods and geometry.

I’m having the frame mods and the swingarm and fork tube stretch done here.

Here’s the modded frame and swingarm, attached together on the roller. 40 deg rake!

Here’s the mods to the headstock, seen from inside

Fork upper tubes extended 6.5 inches and reinforced

Two sets of tubes were used to make these extended tubes (no, I couldn’t just buy them)

Got the engine into the frame

Bit of rash on the left side there

Missing the rubbers for the front mounts – on order from Bike Bandit

Engine right side looks fine

Now for the forks.  Here’s the stock innards.

Stock spring spacer is 30mm dia – same as the OD of 1” PVC pipe

Stock spacer is 50mm.  New ones are 184mm to give an extra bit of preload

Stretching the damper adjustment rod 6.5” requires 10.5” of 7/16” square tubing

Turns out 7/16” square tubing ID is 10mm – fits the 10mm dia rod perfectly.  2” overlap.

Welded up

Here’s the parts for the 6.5”-extended fork innards

And here they are assembled in the forks!

Here’s the front end installed.  A bit tilted on the roller…

A bit less whopperjawed perspective

Trimmed off the back of the frame (known as “bobbing”)

Added the stock fairing support, which I’ll mod to hold headlamps only

Here’s how it looks so far

Throttle bodies installed

Here’s how it looks with the shorter swingarm and air filters installed.  Starting to look like a chopper.

11/15/2014 Spent most of the day finishing up the wiring connections to ~90% done, attaching the emissions systems, and swapping the extended swingarm for a stock-length one (I think it just looks better as a chop/bob).

9/13/2014 Installed chain, some wiring, front support for headlamps and such, and the throttle bodies.  I have an ABS wiring harness, I’ve found, so I’ll have to swap it out for a non-ABS version before too long.

8/26/2014 Front end all put together, and installed on the frame.  Starting to look like a ratbike.  Noticed the 2009 triple tree barely turns before hitting the 2011 frame steer stops.  A bit of grinder work is in order.

8/25/2014 Modded the fork innards and am working on reassembly.  Not as straightforward as I had hoped, but I am either stronger or smarter than the fork assemblies so: they WILL go together.

8/21/2014 Put the engine in while there’s nothing but the frame to lift around it.  Engine fluids were all drained, so it was relatively easy to tip the engine onto its left side in the shipping box, raise it with the engine hoist, and then lower it into the frame sitting on its left side on top of the engine shipping box.  Install the right side frame connector, tighten the motor mount hardware, roll it back upright on the shipping box, and then lift the assembly onto the dolly. A piece of the proverbial cake.