PAT, that is an interesting place to pickup a Yamaha. I used to l enjoy shopping at those base stores.

I'm sure you will appreciate this. While stationed at MCC AFB, learned to fly at local aero-club. Guys kept telling me Bud is checking you out! I thought, Bud who? So day comes, about a week later, I walk out to the plane and there is Col Bud Anderson P51 Ace, my checkout pilot. Best flight of my life.

PABDT -   Thank you brother.  Today, I removed the foam air cleaner and spark arrestor.  Ran it in garage (with the door open-neighbors please forgive).  I've tried every main jet from 90 to 200 and every step on the needle.  Doesn't matter.  So when I started it, after it warmed up, I slowly opened the throttle all the way (in neutral of course) and the rpm's peaked at about 5,500 and then rapidly declined while holding the throttle wide open.  These were Mark's suggestions and thank you Mark.  I would like to take you up on your very generous offer of loaning me your working CDI.  Please let me know how to do that.  Can I send you VENMO to cover the shipping and your time?  Pat     PS  My dad was a P-51 ace in WW2 and my grandfather was a pilot in WW1...gotta be in the blood.

I agree with Mark, because of the timing issues things appear to be possibly coil winding related, but I still question whether the CDI capacitor is up to the job on your bike also.  IE,  possibly both coil and CDI box.    The good news is the CDI box is plug and play to test.

I will send you my CDI box and pulser coil attached to the plate along w/coils which were removed as I was going to clean up the plate and never got around to it.  Keep in mind, I knew I was ordering a VAPE system and never cleaned this up!  Honestly, would recommend same or points system from a 250.  Believe forum member DEET may even rewind old coils and have seen him post for sale a pulser coil noting the resistance was verified.

The stator coil is showing 140 ohms in high 90's F today. Pulser coil is about 101 ohms. Note, I thought I read Yamaha does resistance testing at 68F. Today is high 90s (thus higher reading or their +10%), suggest pulser coil reading is likely in spec. I don't know what the correct stator coil resistance is supposed to be. RT325 states in area of 300ohms. He may very well be correct.


CDI BOX : (connectors are in tact)

connector 1:
ORANGE: charge to ignition coil, in turn triggers secondary charge to plug.
BLACK/WHITE: when grounded, acts as kill switch.  ignition key OR right handle bar switch in off position = ground.
BLACK: ground

connector 2:
WHITE/RED: pulser coil signal
WHITE/GREEN: pulser coil signal
BLACK: ground
BROWN: stator coil charge to CDI capacitor.

If I have made an error in labeling, someone please kindly correct. 

There will be NO CHARGES.   Your family has paid for it already.  Please send your address via message and I'll get it right out.  Wish I had a better plate to send you. Also, I don't need it back.
 

One other simple thing to try is simply unplug and reconnect the CDI box connections.  (And of course clean and repair if they look bad)

One of the bikes at an Endurofest years ago was acting up and someone suggested reseating the CDI connections as they had luck doing that on their 360.   Believe it or not, it worked and the bike ran fine all week.

Don't think i'm up on the play on this post but I feel it's most important to have a reasonable length good audio video to diagnose things like this so you're not chasing ya tail.
It helps to live out in the country for sure & away from neighbors.
Can you trailer it outa town to do a vidio.
Try muffler completely off while you're at it.
Just don't cause a fire by sparks if it's dry where you are.
I always think exhaust when motors go flat at revs or resist revving--if ive not already said that.