Building a Mad Dog: Suzuki VanVan Flat Tracker
The Start of It All
On the 8th of March 2025, a van pulled up with a rolling frame, an engine, a box of loose parts, and a V5 — and that was the sum total of what I'd bought: a 2004 Suzuki VanVan. No guarantee any of it worked. Just the bones of a bike and a plan.
The plan was to build a Mad Dog class flat track bike in time for the Bike Shed Motorcycle Show 2026.
Why a VanVan?
I'm 6'4", and anyone tall who has thrown a leg over a standard 125cc bike knows the problem immediately — they're built for riders half a foot shorter than me. The VanVan solved that. Its wheelbase runs around 100mm longer than a typical small-capacity bike, which gave me the room to actually fit the thing properly, rather than folding myself onto it.
The Mad Dog Rules
Mad Dog is a UK flat track class with a specific and fairly strict rule set: 200cc maximum displacement, air-cooled, two-valve, four-stroke engines only, running on 17-inch wheels front and rear. No shortcuts on capacity, no water cooling, no fancy multi-valve heads — just simple, honest engines built to be thrashed round a dirt oval. That constraint shaped every decision on this build.
Stripping It Back
The bike came apart completely. The frame was stripped bare, modified to accept a new seat and tank, and painted. Once the rolling chassis was sorted, I moved onto a part of the build I'd never tackled before: lacing a set of 17" DID rims into the front and rear hubs myself. First time doing it, and getting those spoke tensions even and the rims running true took patience, but it was worth learning properly rather than farming it out.
The wiring loom got the same treatment as the frame — stripped down to the essentials, no more than what the bike actually needed to run, then cloth-wrapped for a period-correct look that also happened to make it easier to route around the new bodywork.
The Big Bore Rabbit Hole
To hit the top end of the Mad Dog capacity limit, I went with a 150cc big bore kit and a high-lift cam. But once the bike was running, curiosity got the better of me, and I 3D scanned and modelled the barrel, piston, and head to see exactly what I was working with.
Alarmingly, I'd machined my own domed piston to lift compression, and the real-world figure it produced was 13.7:1. For an air-cooled two-valve single running on pump fuel, that is an enormous compression ratio, and if I'm honest, I'm still not entirely sure how it didn't grenade itself on the first test.
It turns out that ignorance was only ever temporary. Not long after, the engine snapped a valve, taking the piston and head out with it. A full rebuild followed — and it landed just a week before the Bike Shed show, which made for a tense final few days of turning spanners rather than admiring the paint.
Out on Show
Despite building the bike with the intention of keeping it pristine for its show debut, I couldn't resist getting it out racing at my local speedway track before the big day. No crashes, thankfully — just the aforementioned blown engine, sorted in time.
The bike was entered into the Kickback Custom Show, and then made its way to the Bike Shed Motorcycle Show at Tobacco Dock — a genuinely brilliant event, and a fitting place for a build that had gone from a box of parts to a finished flat tracker in under a year.
None of it would have come together without help. Thanks to Revved Up Motorcycle Coatings for the paint, Rally Raid Products, Cobuilt Geoff, Mytini Racing, and R.H. Weldfab (aka Ruaridh the Racing Car) for all their contributions along the way. And a nod to Iwade Flat Track — home of Mad Dog racing in the UK and a genuinely great bunch of riders.
What's Next
With the show circuit done for now, the VanVan is back where it belongs — racing at Iwade. No more guilt about track time cutting into show prep. Just guilt-free racing, and the payoff of finally enjoying the bike I spent the best part of a year building from scratch
