I have a 1981 Yamaha YZ465 that is an absolute terror to start cold or hot. I can kick and kick and kick without it even popping. It will give an occasional backfire. Then out of the blue it will start.
I have been through the carb repeatedly to make sure all the passages are clean. replaced the pilot jet, the needle and seat, needle jet and jet needle. Put a new set of rings in with proper end gap. Checked and rechecked the timing several times. Changed to new plugs. Checked spark.
There are times that it will start right up. Most of the time it wears me out kicking. A 465 hurts the bottom of you feet after repeatedly kicking. I also have a new crank seal on the mag side. It does not mean that it is not leaking but it is new.
I noticed last night when I got it started that it had a air sound coming from the carb and it sounded like out the back. I also have a problem with it falling flat on it face at high rpm. Nice and crisp from low idle rpm to about just above 1/2 throttle. Then it falls flat and sounds like it is a 4 stroke.
My carb has a 45 pilot, stock needle and needle jet . The needle jet is on the top clip the leanest setting. I also have a 380 main which is one size smaller than stock. This thing is driving me nuts and I cannot seem to get a handle on it.
Any help or ideas would be appreciated.
Tired old man
Thanks
Jack
I have been through the carb repeatedly to make sure all the passages are clean. replaced the pilot jet, the needle and seat, needle jet and jet needle. Put a new set of rings in with proper end gap. Checked and rechecked the timing several times. Changed to new plugs. Checked spark.
There are times that it will start right up. Most of the time it wears me out kicking. A 465 hurts the bottom of you feet after repeatedly kicking. I also have a new crank seal on the mag side. It does not mean that it is not leaking but it is new.
I noticed last night when I got it started that it had a air sound coming from the carb and it sounded like out the back. I also have a problem with it falling flat on it face at high rpm. Nice and crisp from low idle rpm to about just above 1/2 throttle. Then it falls flat and sounds like it is a 4 stroke.
My carb has a 45 pilot, stock needle and needle jet . The needle jet is on the top clip the leanest setting. I also have a 380 main which is one size smaller than stock. This thing is driving me nuts and I cannot seem to get a handle on it.
Any help or ideas would be appreciated.
Tired old man
Thanks
Jack