Johnlucien

I had the same problem two months ago. We fitted a new KTM EXC380 piston (fits our BFA perfectly) and had the cylinder's Nikasil coating redone at Airsal. Regarding the carburetor, we adapted the manifold to install a VHSB 34. However, carburetor adjustments are complicated with these engine sizes. Since the breakdown, I no longer dare to ride at full throttle. I'm continuing the adjustments, but as you say, it's difficult to adjust the needle and the diffuser.

During a ride with my buddy and his SSR265—where we love to push hard on the throttle—we hit a stretch of highway. My BFA seized under full load, trashing the piston and stripping the Nikasil coating right off the cylinder. The Rebuild: We hunted down a replacement piston and went with a KTM 380EXC unit. It’s a perfect match for the BFA but way cheaper at €190 (vs. SIP’s €300). For the cylinder, we did some light porting: raised the exhaust port timing and tweaked the transfers before shipping it to AIRSAL in Spain for a fresh Nikasil coat. While waiting for the cylinder, we fitted a 34mm VHSB carb, reshaped the intake tract, and machined it for better flow. This thing is a monster now. The BFA just rockets forward with every twist of the wrist—torque is through the roof, and acceleration is brutal. Couldn’t be happier with how it turned out!

Following Arne's feedback, we modified the BFA piston by incorporating grooves to accommodate KTM 300 EXC circlips. We also added lubrication holes for the piston pin and made a few other minor modifications. On the exhaust side, we also worked on reinforcing the elbow and installing protective covers.

Solo, no 3M this year, we plan to go to Eurolambretta from western France

Hello, I just installed a BFA325 on my S2. We reworked the port timings to get 123 on the intake and 183 on the exhaust, installed a 2mm spacer under the reed valves, rebuilt the intake manifold and increased its internal diameter to improve flow, fitted with a Cyclone 5 gearbox, 47/20 gearing. Carburetion is currently being adjusted K24 needle, third notch from the top, DQ 266 mixing tube, 155 main jet, B34 atomizer under the secondary jet, 38 slider. The mixture is rich. After 150km the engine is running very well, lots of torque, it holds its own against my friend's SSR265 😊