My obsession of late is making my Manco Carbide 265CC go kart faster. The kart has a Subaru Robin 9 hp engine. I have made an intake for it as well as a header (yeah... I have lost my mind). I have drilled the main jet to a larger size. The plug was showing very lean when I first ran it, which it would after increasing air flow. I now have a nice brown color on the plug which to me would indicate a pretty good burn. I have completely removed the governor linkage and engine internals. I'm certain I'm getting WOT. The fuel comes from a tank mounted well above the engine and it is gravity fed to the engine.
The kart is rated at around 675 lbs IIRC. The tires are 20x11x8. It has a series 40 Driver and a 7.5" Driven torque converter. I have played around with spring tension on the torque converter. The sprocket on the jackshaft the Torque converter is on has 12 teeth which goes to a 24 tooth sprocket on the rear jackshaft. From there it goes to another sprocket with 18 teeth down to the axle with a 60 tooth sprocket. There is also a reverse gearbox on the same jackshaft as the 24 and 18 sprocket at the rear.
My problem is, the engine isn't winding up under load. With the tires in the air the thing will scream. Once I drop the tires on ground it hits a point like it's still being governed but it can't be because the governor is totally gone. On smooth pavement it seems to wind up better as I can get 34 mph out of it. If I go off road, it drops to about 25mph which seems extreme. On the road or off, I can tell when the engine has hit all it's going to do.
Beyond the modifications to the engine intake/exhaust/carb I have checked the brakes to make sure they aren't tight. I have checked for tow in to see if it was plowing and adjusted to reduce drag. I'm just lost on where to go from here!
He it is in all its glory!
