Blown Superbike-Powered Flat Tracker from Finland…
There must be something in the water in Finland. Maybe it’s the dark winters, the sisu culture of grit and resilience, or the long history of racing on dirt, tarmac, and ice, but the country continues to produce some of the fastest racers and wildest custom machines on the planet. Recently we heard from Janne Leiman of Finland’s JL Meccanica, who builds one-off classic race frames along with performing custom bike work. For example, he built the replica Ceriana forks on Cédric Camiade’s Norley — one of our Top 10 Custom Bikes of 2025.
When it came time to build a bike to promote his workshop and race at local flat track events, the Finn decided to go all-out and build a bike from the ground up. Let’s start with the engine, which is a real unit. It consists of a GSX-R750 bottom end mated to a GSX1100 head and overbored cylinders, complete with Kawasaki ZX-10R pistons, custom 7075 con rods, and GSX1100 cams.
That might be enough to satisfy some builders, but Janne went farther, giving the bike a draw-through supercharger system consisting of a VW-sourced Eaton M24 blower with a big 48mm Honda VTR1000 / Keihin carburetor with double float chambers on fueling duty. Janne fabricated the exhaust and silencer from scratch and modified the gearbox down to four speeds, which, he says, is still more gears than the bike needs.
Janne built the frame and swingarm from Docol R8 steel tubing, mainly using Indian FTR750 geometry, and outfitted the chassis with Kawasaki ZX-9R and ZF-Sachs rear suspension. Interestingly, Finland allows front brakes on flat track bikes, so there’s a small disc up front and big four-piston Brembo caliper in the rear.
The bodywork is made from fiberglass, and the tank comes from an unknown custom bike, modified to fit the frame backbone and an Acerbis fuel cap.
Janne wasn’t quite happy with the power delivery in the initial testing — the torque was in too narrow the rev range — so he has the bike back on the bench, making updates before riding / racing season begins.
We can’t wait to see this own blown big-block Suzuki on the dirt. It would be hard to imagine a beefier, more muscular flat tracker, and it’s going to take one very brave and skilled pilot to tame this supercharged beast.
Below is our full interview with Janne about the build, and stay tuned for more performance bikes from this Finnish workshop.
JL Meccanica FT900SC: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
My name is Janne Leiman, I live in Finland, a little town called Mänttä. I have owned and ridden motorcycles from thirteen years old, so over 40 years now. My workshop is named JL Meccanica, which has been my day job since 2007.
Main products are one-off classic race frames and suspensions. Occasional custom bike work too, for example Cédric’s Norley (featured here) has Ceriani front fork replicas made by me.
• What’s the make, model, and year of the donor bike?
No particular donor, bike was made from the ground up.
• Why was this bike built?
Bike is built for company promotion, to race in local classic flat track events.
• What was the design concept and what influenced the build?
It is flat track bikes where the main lines came from. Their geometry etc. has most influence on the bike. When looking at it now, local tracks may be too short to fit this type of motorcycle.
• What custom work was done to the bike?
Well, the engine is made from a GSX-R750 bottom end mated with GSX1100 overbored cylinders and head. Cams are also from the 1100, cam drive is GPz750. Custom-made 7075 aluminium connecting rods are moved by ZX-10R Kawasaki pistons. Crankshaft modified so that a pit bike alternator can be mounted in the left end.
Supercharger is an Eaton M24 from VW. Carburetor came from Honda, VTR1000 pair split and one of the 48mm Keihins attached to the intake side. So a draw-through system.
Exhaust was made up completely, including silencer. Gearbox modified to four speed, which is still too many gears.
Frame and swingarm were made from Docol R8 steel tube, geometry copied mostly from Indian FTR750. Rear shock parts came from Guzzi and Husqvarna, both used ZF-Sachs brand, so mixing was quite easy. Front forks are Kawa ones, ZX-9R, only minor modifications there.
Here in Finland front brake use is allowed, so minimal disc is mounted in front too. In the rear a bigger one is in use, with four-piston Brembo caliper.
Body parts made from glassfibre, and fuel tank is a steel one from some unknown custom bike. It was narrowed, a new tunnel made, and threaded for an Acerbis cap. Seat consists of some moped cover stretched to base made from plastic sheet.
• Was there anything done during this build that you are particularly proud of?
Carburetor with double float chambers and its other modifications was quite tricky. It was made because fuel need for supercharged engine is high and I didn’t want to use a fuel pump.
• Is there anyone you’d like to thank?
Hakala Service for delivering rear shock parts, Kevin Porter for zinc plating numerous parts, and Juha Tanila for sponsoring some engine parts.
Follow the Builder
Facebook: JL Meccanica
Instagram: @jlmeccanica
Photos: Lea Antola
It is quite big bike for Flat Track, isn´t ?
But very interesting build.
Well, he used the Indian FTR geometry, and that’s been the most successful machine in the modern SuperTwins class of American Flat Track.