on my 340, i have a single mikuni carb. How do i tell the size of the carb. Do i have to measure something. I'm looking for a rebuild kit for it. My sled starts and runs for a few seconds then dies. So i'm putting new pistons/rings/ needle bearings/gaskets in it. I also want to rebuild the carb and clean it and put new plug wires on it. This should fix the problem right. one of the old pistons had a hole starting to form in it. its a twin cylinder
To determine the size of your carb simply measure the diameter of the throat on the engine side of the carburetor. The measurement should be done in millimeters as that is what Mikuni goes by.
As far as the engine goes don't forget to put in new crankshaft seals. These are notorious for leaking and causing erosion of the piston as you described. This also could be caused by low octane/bad gas, advanced timing or an air leak somewhere(seals?). Also make sure the gas tank is clean as any water could cause you problems as well. To be sure drain it out and put a fresh premium gas in it.
thanks for the info. Does anyone know of anygood places i could get the parts from? When i put the head back o should i just torque it to like 100 inch pounds? Also how do i set the ignition timing? I took small engines in school but i neer learned how to set ignition timing.
Since your doing all that ... put all new gas lines on and change the points . does it have a plunger on it ? if so make sure it is working the right way , I had an old sled and the plunger was sucking air .
yup i am. I'm orderin full gasket kit, fuel lines/in tank filter, in line filter, fuel pump rebuild kit, carb rebuild it, points/ condensors/ plugs/ plug wires/pistons, rings. and some other stuff i just forget. This fall i'm putting new shocks and ski's. The year after i'm doing the track. the points and condensor is under the flywheel right. I have to change the crank seals so i'm just gonna pull the engine. Does anyone know the head bolt torque and the flywheel torque? Also, does the clutch have to be torqued? This is my first sled. I also ordered a clymer book for vintage sleds maybe i'll find it in there.