fixed it

I'd better go read about the fuel optimizer after thinking OP was using a 'way too small' in the pilot jet. Always new things to learn. Was thinking bigger carb needs bigger pilot as has a slower air flow. I'll go learn a thing or two.

Hey RT325, you know a boat load more than I do about these things.  Back in the day when I was riding my 175 and 400 the only thing I knew what how to change piston and rings, I have a lot to learn!!!

Bigger carb dont mean bigger pilot , if the slide has to be open a certain amount to allow enough air to idle at 1000 rpm for example the same amount of air is required for any size carb, But when the slide opens then requirements change . 

Hey, i know enough to get myself into trouble playing around haha. Then need the likes of RacerClam to sort me out.

Ok group, I put the needle on the second to the top clip, so lowered it and made a WOT run.  The motor was good and warmed up before video.  I must say it is better than yesterday but as you will see it can cutout pretty bad once it gets wound out. 

WOT run

Thanks for inserting the video Mark, I'd do it if I knew how.  Since I haven't gotten any suggestions I'm going to buy a 210 main jet (has 200 in it now), and give that a shot.  I will also get a 17.5 pilot as Rich suggested but want to tackle issue at a time so I wont install that at the same time so as to not muddy the waters as it were. 

Just listened to the video above & still stick to my ignition electrical first thought!!.

So what would you suspect, coil maybe?  I have new point and condenser in, put them in a few months back. 

An easy place to start is to make sure all of your ignition grounds are good.  One time I put new points in and had similar poor running engine with a points base that had 20 ohms resistance to ground.  Cleaned the engine case where the points mount metal off, got a zero ohms points base reading, reassembled and it ran like a champ!

With magneto ignition you can do the following:
1. Disconnect the secondary coil under the tank.  This is usually a black wire to the coil.
2. Turn on the ignition.  On a magneto ignition, this disconnects the short to ground that stops the ignition from working.
3. Turn the engine to open the points. 
4. Find a good bare metal ground on the frame.  Use this as the connection for one of your good ohmmeter leads.  Make sure your ohm meter reads zero or nearly so with the two leads shorted together before you start.
5. Test the secondary coil frame to ground resistance.  Should be nearly zero.
6. Test the engine cases to frame resistance.  Should be nearly zero.
7. Test the condenser outer case to frame resistance.   Should be nearly zero.
8. Test the points base to frame resistance.  Should be nearly zero.
9. There is also a ground from the source coil under the magneto you can check.

If you get more than a one ohm reading in any of steps 5 through 8, you are either doing something wrong or you found a problem.

When I say nearly zero, it should only read a couple of tenths of an ohm more than what the meter read in step 4.

Don't forget to hook up the secondary coil when you are done.

The grounding might not be the problem, but it is a good thing to rule out.

Good luck.