The latest on this project:
I installed the milled and ported heads along with a set of stiffer valve springs. I had to sand down the intake manifold so it would seat correctly to heads. After putting them on, I took it for a ride and the thing sang right up over 5k RPMs and promptly died. I was like, WTF?? It started right up no problem, but upon another
WOT (Wide Open Throttle) pull it shut off again. What I eventually determined is that the
Engine has a rev limiter somewhere in its very limited electronics. After disconnecting the kill wire, it rev'd just fine.
So the head work and valve springs definitely woke it up and allowed it to produce power out to 5k. Prior to that, you could really tell that after 4k the torque was dropping off. But that wasn't good enough. I really wanted to try something (even more) different -- a long-ram dual carb intake. So I put to use my new-found (and limited) skills of 3D design, 3D printing, and lost-wax aluminum casting. After several resin prototypes, I cast an aluminum two-piece manifold and used Alumiweld to join the tubing. Feeding the intake is a 24mm and a 34mm PWK carb controlled in a primary/secondary arrangement by a cam that I also designed and 3D printed.
It was a LOT of work and I had no idea how the result would be. I was preparing myself for disapointment. Fortunately, it worked! And not only did it work, it did give me a boost in power. So much so that I felt it was time to rebuild the reduction unit and install the alternate gearset. With the new gearset it has a top speed of about 45mph which is plenty fast for this chassis and it pulls hard.
My brother and I did a few drags with it against my mostly-stock FL350 and the FL250 would leave it in the dust from a dead stop because it digs in and just goes while the 350 does a lot of spinning. From a rolling start, they seemed pretty equal.
So I think I finally have this FL250 where I want it. I consider the project complete but not finished. The carbs still have the factory jets and needle adjustment so may benefit from some fine tuning. Overall it needs to be cleaned up and I need to fab some Engine shrouds to help with cooling and maybe a larger oil cooler.
It's kind of a crazy set up I admit, but I (mostly) enjoyed the work and learned some skills along the way that I'll use on future projects -- and that's what it was all about!