Last weekend was the first time I took my KX400 out for a race. I had never run it before, and I was having some issues tuning in the carb. It is the stock VM36SS Mikuni unit. Stock jetting, and it was pretty clean when I got the thing, and I cleaned it very well on top of that.
It had a dead spot from closed to 1/4 throttle or so. After that it ran fine. Usually, that means the pilot jet, but it was clear...even tried a new one. The funny thing was, it ran fine with the choke on. Better then fine. Superb even. I rode a whole moto with the choke on.
So i guess a richer mixture did the trick so to speak. Then again, with the choke off, it ran ok if you could ge past the dead spot.
what about this: The slide. It was missing from the bike when I got it, and I put in another mikuni slide that I had laying around. I know that slides come with different cut outs. Could a cutout be wrong enough for a bike to cause that dead 1/4? (come to think of it, I had better check what side the cutout is on! it could be a slide from a reverse carb with the idle screw on the other side. I ran into that on one of my triples---had the odd slide in the wrong carb and the cutout was facing the cylinder!) :yikes:
It ran so nice with the choke on, I may fix it in that position if it comes to that. The plug was fine, and it did not over heat or anything, but I wuold like to find out just what is going on here.
It had a dead spot from closed to 1/4 throttle or so. After that it ran fine. Usually, that means the pilot jet, but it was clear...even tried a new one. The funny thing was, it ran fine with the choke on. Better then fine. Superb even. I rode a whole moto with the choke on.
So i guess a richer mixture did the trick so to speak. Then again, with the choke off, it ran ok if you could ge past the dead spot.
what about this: The slide. It was missing from the bike when I got it, and I put in another mikuni slide that I had laying around. I know that slides come with different cut outs. Could a cutout be wrong enough for a bike to cause that dead 1/4? (come to think of it, I had better check what side the cutout is on! it could be a slide from a reverse carb with the idle screw on the other side. I ran into that on one of my triples---had the odd slide in the wrong carb and the cutout was facing the cylinder!) :yikes:
It ran so nice with the choke on, I may fix it in that position if it comes to that. The plug was fine, and it did not over heat or anything, but I wuold like to find out just what is going on here.
