THE STORY ///
Like most the bikes we build this one started as a couple hundred dollar purchase and very little information known about the bike. For all its corrosion, bad body work, and missing parts, the bones looked pretty solid so we took a chance on it. We were lucky enough to get find Jadus Performance who make performance parts specifically for the SR250. Jadus is a Swedish company that specializes in aftermarket motorcycle parts and accessories. They have started with a range of parts and accessories just for the SR250. Though these bikes aren't as popular in the U.S., they share the same engine as the XT250 in the same years and the engine design is similar to proven Yamaha ATV designs.
PERFORMANCE PARTS ///
Here's what Jadus says about their parts:
EXHAUST – The header we developed is a single wall design, made from high quality Stainless Steel and has an effective diameter of 32mm - allowing for a much greater flow of exhaust gas and an increase in power of 10%+. Used with a suitable silencer, weight savings are upwards of 1.5kg!
INTAKE – Our tuned intake design has a specially formed bell mouth entry that fits inside an oversized high performance clamp on foam air filter. This filter has a large surface area and allows a high volume of clean air into the engine at high velocity.
IGNITION – Through research and testing, we found the SR's peak ignition advance to be a little conservative. So we developed a special advance bracket kit to raise the ignition curve a few degrees. The extra advance helps raise cylinder pressure at the correct time in the combustion process and translates to a cleaner more efficient burn and more power - giving higher mileage and crisper throttle response.
THE BIKE ///
These bikes are great, the engine is a modern design compared to 4-strokes of the 70s and it shows. With the performance parts you can tell there is an improvement over stock plus these are basic upgrades that can be done in an afternoon. The header is a no-brainer, the stock pipe is actually a double wall pipe with the inside diameter close to 1 inch, that's tiny. The Jadus pipe opens that up and helps it breathe. We used a Supertrapp muffler as they're tuneable and sound decent. The other key piece of the kit is two CNC'd brackets that relocate the ignition pickup, advancing the timing. Its a simple solution that utilizes all the stock ignition components. Big thank you to Jadus Motorcycle Parts for all their help!
I can't wait to really put it to the test on the 'ol dirt oval!