250 cc yamaha serial # 25y-000165 what year and model tech?
1983-1985 Yamaha IT250K.
You need several things to get it to start: A clean carbuerator, a good reed cage, a good, clean spark plug, and compression.
Start by pulling the spark plug. If it's oily/dirty, replace it. Then kick the engine over, and you should get the motor to turn over really easy. Place the plug back into the hole, and the effort to turn the engine over should be hard, if there is compression. If there is no compression, you need to remove the cylinder head to find out why. It could be a hole in the piston, bad rings, or worse, bad crank seals. If the piston looks okay, then chances are the problem lies in the Mikuni carbuerator. It's an simple device, but you need to make sure the needle seals the bowl when the float level is correct. You also need to make sure your air enrichment circuits are free of dirt and varnish. Give it a good scrubbing. Once the carb is clean, and the float level is sound, make sure to check the air filter to ensure it is clean. The carb ensures fuel is correct. Lastly, there is spark. Your plug wire shouldn't have any cracks, and when you crank it over, there should be a spark from the plug. There is a remote chance that the pickup coil has burned out, but the ignition system on these old Yamahas is pretty reliable, so look there last of all.
Apr 13, 2009 |
2003 Yamaha YZ 250