Hey, while the fzr250 is quite rare, i have a question: is it possible to convert a fzx250 to fzr250? There is a opportunity for the zeal... Thanks spark
Yes. Engine bottom end and cylinders are the same. Cylinder head/camshafts, ignitor unit, exhaust and carbs are different. Speculation that 3YX Zeal, 3LN6/7 camshafts are the same. Both have reduced redline of 16,500RPM from 18,500RPM of the 3LN1/3/5 What you will need is a complete FZR250 3LN cylinder head with camshafts, matching ignitor unit (TCI) and carburettors/airbox (including inlet manifolds) for a barebones conversion. It will probably run with Zeal carbs but won't be happy. Be a good idea to steal the carb vacuum slides and needle retainers to transplant into the 3LN carbs if possible, due to poor needle retention and issues with needle/emulsion tube (jet needle and needle jet) wear on the 3LN1, 3LN3, and 3LN5 models. 3LN6, 3LN7, and 3YX Zeal all use improved needle retainers and do not suffer from needle/tube wear. It is preferable to have the FZR250 3LN exhaust system with EXUP, so you will need headers and servo motor. This will require a 3LN wiring harness as it will have the plug for the EXUP motor.
Okay, many thanks for this detailled information. I already have 2KR Engine in spare. What about chassis and frame?
2KR camshafts are higher performance than the Zeal and much closer to 3LN - there is a slight difference in duration and timing between 2KR and 3LN1/3/5 camshafts 2KR connecting rods are 80mm centre to centre with the difference in the pistons compression height as compared to: 3LN1/3/5/6/7 and Zeal connecting rods are 82mm centre to centre with the piston compression height being 2mm less All of the above differences (camshaft, connecting rod and pistons) are detailed in the Yamaha FZR250R 3LN1 Service Manual Supplement in the resources section
