Your clutch issue "might" be what happened to me last week: viewtopic.php?f=1&t=19501

What is your setup again? Carb and all?

CR500 jug on a PWK39 carb? High compression? High octane? Pipe?

While I cannot be absolutely/too sure, that setup you've got might actually like a larger carb or an opened up intake. On my setup, I've got a FL400 @ 81.5mm with a PWK39 and I've tuned it with my wideband on a 168~170 main jet. I've tuned this with a wide-band O2, and EGT, and she runs 12.3:1 @ 1240F. Perfect piston wash too.

See, the bigger the Engine, usually the smaller the jetting required with the carb being the same. This is due to the amount of pressure the Engine is able to create across the carb's venturi. Since you have a bigger Engine than I do, theres a good chance you are pulling even MORE/HARDER than I am, and your 185/200 main jet tests are just way too much. If main jetting is overly rich, the Engine will act like a rev limiter.

Three things I would recommend
1. Open up your intake a LOT. This will reduce pressure across the carb - allow for more air, power etc.
2. Change out to a 42mm carb and re-tune
3. Tune your pwk39 carb

It's a stock jug re-sleeved.PWK40 I've tried main jet from 165 on up to 205.Last plug chops I was able to do the biggest jet I had with me was 188 and plugged look lean as hell,I don't think the missing has been because of rich condition.

What bore size?

90 mm

With all that custom stuff, why not spend the $175 on a Wideband O2 sensor, that way you'll know for sure whats going on a get a perfect tune later on?

Is the Engine passing pressure leakage tests? Whats your Static/Dynamic CR? Whats your squish band measurement? Whats your compression on a gauge?

Yes,don't know,don't know,195

Didnt feel like messing with it last night.The night before when I cranked it over but didnt start it I was pushing on throttle listening to carb,felt and sounded like everything was working properly.I unscrewed top of carb to make sure throttle cable was connected good and everything looked good,which it did,was looking to see if I could find anything that caused the runaway throttle,didnt see anything.
I had a couple minutes before work this morning,I pushed it out and took video of clutch to see if it looked wobbly,it does a little,not sure if this is normal or not.
I decided to crank it and it started up normally with no runaway throttle,so who knows wtf caused it the other night,oh and it did not make that weird noise when shut off either

IMO, the 39 carb should be just fine, the CR500 runs good on the 39PWK, if memory serves me the stock carb on the 500 is a 36PJ

There is something wrong with that 102.
You better pull it and check it out. That's WAY to much wobble. Something is wrong.
May be its just not tight ?? It doesn't look right.
Just my opinion.
CO

Edit: By the way one of the bolts on your clutch face plate is missing or broke off (at 27sec mark). Start there.
CO

Check the runout at the crank with the clutch removed. Something is not right.

I was able to take the pilot to the beach Sunday where I could change out some parts and see if anything made a difference.I changed the coil,CDI (Capacitor Discharge Ignition),and timer and nothing changed,I still have a rectifier I can switch out but haven’t got to that yet,I’m getting so frustrated.
At times during the testing for brief periods of a few seconds here and there it would run without that miss.If you start out slow and slowly creep up to full throttle it does a lot better,But if you’re cruising along, it doesn’t matter at what speed, and gun it it goes to shit,has no power and misses like a mofo.
But every once in a while,for a brief second,I would be at a slow crawl or stop and gun it and it would go good,almost normal like it was before rebuild.

Also,And I think I forgot to mention this the last time it happened, which was the last time I was able to take it somewhere and do some plug shops, my spark plugs will not stay tight(most of the time)
After a run when I stop to change out the plug the plug is loose where I can unscrew it with my hand,Although certain plugs would stay tight and certain ones wouldn’t.Does anyone know what the torque values would be on this aftermarket head? I’m very afraid of stripping it out. I don’t know of anybody selling them or where to get a replacement.

I’m still on 205 jet but I have some bigger ones coming. Who knows if that will change anything, I have no hope at this point.
I did one plug chop with brand new br7 plug(been using br8) I have not cut it open but just from looks it looks very lean

1) I am still leaning towards fuel flow even though you said it was good.
2) The wobble in your clutch didn't look good to me and there is a bolt missing -- see previous comments.
3) The loose plugs suggest the threads in the head are already pulled. If they are shot then it is repairable. You pull the head and insert a helicoil.
CO

These comments are just screaming fuel flow to me.
When an Engine runs lean it -- your comments: "and gun it it goes to shit,has no power and misses like a mofo." -- "I would be at a slow crawl or stop and gun it and it would go good,almost normal like it was before rebuild".
That's because the bowl is full of fuel and then it runs out but the pump still supplies some but not enough. That's what all this says to me.
Just my opinions.
CO

Edit: Is the vacuum line tight at both ends ??
This is going to sound stupid but if you got another pump laying around then "T" the two together and run two pumps temporary to see if it cures this problem.

Sparkplug torque: 13 ft lbs as per manual section 1-5
CO

I put honda oem pump back on{not my old one,but one I received from socalgi}and yes I have clamps on both ends tight.While the amazon pump seemed to pump better on testing in front of my house it was still missing so I just put the oem pump back on to play it safe.

Thanks but do you think the same torque would apply to this aftermarket head?

In my opinion a sparkplug is a sparkplug. Why would it be any different in torque ??
I can only see it being different if it is a cast steel head or an aluminum head. Different metal would mean different torque. But in this case both are aluminum.
All I can think of is that when you put in these new sparkplugs you didn't flatten the crush washer and therefore did not have the correct torque from the get go.
If it strips then the threads were already damaged and was NOT caused by your torquein in a new plug.
CO

Ok thanks,I haven’t googled it,I’ve owned 3 pilots and none of them had stock head,couldn’t remember what they looked like exactly or what they were made of

I've never torqued a plug. I just wrench it by hand make sure that you squish the washer down and I've never had a problem so far. if your plug is loose that would be the biggest problem, your losing power, combustion, compression.

What you’re saying of course makes sense,Unfortunately it did not seem to make a difference whether the plug was tight or not in the way it’s performing,on the runs that plug stayed tight it still ran like shit

I don't know. You seem to have checked everything and also replaced the CDI (Capacitor Discharge Ignition), coil, timer.
This seems to be leaning towards the stator again.
This thing has passed a pressure test, fuel flow test, and several replacement electrical parts. Everything except the stator.
The way you described it above it says fuel to me but you say it passes that so now you gota go stator. That's all that's left. There are a few other issues but I think you just want us to concentrate on Engine. The other issue that I am talking about is the clutch video but I know you want the Engine solution first. Go with the stator now and at least rule that out.
CO

I had a plug come loose last year, cost me a lot. I now torque my plugs to 21 ft. lbs., I have not had one come loose since. I did use to go by the manual.

I have listened to the video of you on the beach over and over again, I know everything is pointing lean but in the video it sounds rich.
Yes I agree the plug looks lean but when you did the plug chop did you hold it wide open and let it miss some then shut it down and pull the plug?

The big things I think need to happen before you run it anymore is, why did the Engine race on you, where did that spinning noise come from, use a stethoscope to pin point the noise ( probably have to take apart the right cover and find it but try and pin point first, I can not think where else it could come from), another leak check at 7 psi for 30 minutes with no loss of pressure (pressure not vacuum), if you lose any pressure find where it went. If the exhaust was restricted it would run like it does but the plug would come out powder rich so I do not think exhaust, check anyway when you remove for leak check..

I am also wondering if it would be possible for the crankshaft key to break just enough to set it out of time some but the nut is still holding it pretty much in place, or at least enough to run. If this did happen it would explain why it will not rev out and sounds rich but looks lean. I would also pull the flywheel and check when you take the right cover off.

I am concerned about the reeds as well, I know you said they are new but a week reed pedal will cause some problems, from what I have dealt with a rich or flooding problem. The ones that went bad on me had frayed ends. I am thinking maybe a defective reed pedal, I am not sure what that would act like just fishing for the problem.

Well I haven’t had a chance to get to this, back at it today. When I was doing my leak down test before I had a high pressure gauge, I was told I need to get a low pressure gauge so I did and I was doing another leak down test today and I found a leak that either I did not see before or it wasn’t there, very small bubbling coming out around the carb boot bolts into reed cage.At first it was just a little bit on one side at the top, tried tightening the bolts on each side and that just made it worse and made it leak on both sides(where marked in red)
I have taken the carb off so many times now that I could have made it worse, I don’t know if it has been like this the whole time or not.It looks like it had some kind of sealer around it before like Honda bond, so can I just put some more Honda bond around it again to seal it up or do I need to figure something else out?
Thanks

Well I could not wait on a response any longer, I had to get the buggy loaded on trailer and back in the garage before the rain hit. I wanna head and put a thin coat of Honda bond on it and put it back on and will mess with it some more on Sunday and do another test