Was your spark plug that you used for the plug shop brand new, I seem to remember that I had to put some hours on the plug before it would give me a good reading., Also the plug had a white powdery substance On it, I wonder if anybody can chime in as to what that would be

Yes plug was new,everything I've read and youtubed says use new plug for chops.Use old plug to warm up Engine and get to spot where you want to do your chops,then switch to new plug and haul ass

New airbox is 14x10x5 with main filter 2 1/2" id and 4" tall but I have one ordered that's 6" tall.Also has prefilter with 2" id and 4" tall

So I took Kuma's advice and bought a wifi bore scope,works pretty good for 25 bucks.I see nothing incriminating on the video.
Also I jacked up the rear of buggy today,put it in gear and went wide open 3 times for a few seconds and did not hear that noise that's bugging me,{have not changed belt yet CO} So that's a good thing,so hopefully I can eliminate that being the Engine

Damn crickets in here,is no one impressed with my whore scope?
Got new filter in so did some more work to airbox. Put the new 6” filter as main filter and made the one that was on there into another pre filter

The bore scopes are awesome. How much is a whore scope and does she come problem free? I used Chads when the intake boot tore at the dunes to see if I had done any damage by possibly running it lean or sucking in sand. All looked good and I didn’t have to tear it a part. I posted a video on YouTube and I think here as well. What brand did you get ?

16.99 shipped on Amazon,can’t hardly beat that!

On side note,Does anyone know how to stop iPhone from from making all my freaking picture sideways!

I'm at my wits end.Took buggy to a place yesterday that I could do some long runs for plug chops.I had already taken off the chinese pwk 38 and put on a brand new chinese pwk 40. Started out with 170 main jet,too lean,went all the way up to highest jet I had{190} still running lean and still not running good.I have low end power but no top end and it's missing when wide open.So before spending 50-100 bucks on more jets I thought I would try my original carb.
So today I put my old genuine pwk 38 I had on it before,the one that was on it when it blew.Again starting out with 170 main jet,which is same jet it had in it before.So everything is back to the way it was before rebuild except for the bigger airbox I made.
Cranked it up,way too fat,buggy will barely moved when giving full throttle.Plug is black and wet.Long story short,went all the way up on needle,down to 142 main jet,running it without lid to airbox,running better but still too rich and still missing even worse than before.
This makes no sense to me,I cant believe that bigger airbox would make that much difference to have to go all the way down to 142 jet and still not be good enough,and why is it missing!! I think there's got to be some kind of electrical problem going on somewhere

I have to comment on this statement.
That's similar to what happened to our machines. Our fuel pumps were putting out enough for bottom end but at mid range and top end they were just flat. No power.
A few years ago I had a cracked intake and didn't know it and that's when my machine started missing. Then it blew a con rod lower bearing because it ran so lean.
Basically what I am saying is that if your Engine is missing or is flat but the low end is good, then you are starving on fuel. Be careful.
Your air box is doing funny things when it has the lid on and another when it is off. Caution is in order here.
Start with verifying fuel flow first.
CO

I'm not sure what youre basing that statement on about lid? I havent been experimenting with lid,I just took it off today when I got down to my smallest jet and it still seemed like it was running rich so I took lid off to see if it made a difference.You are right about one thing though,I do need to verify fuel flow.I have clear fuel lines and I can see the gas flowing to carb,looks like it gets there fast but I have not ran a test.While it was idling today I sprayed carb cleaner all around the intake to check for air leaks and found nothing

Red,

I’m sorry I have not looked at this thread before now. I really can’t give you jetting advice on the Chinese carb, but I suggest you read my two threads here on tuning pwk.

Slide numbers
viewtopic.php?f=1&t=18049&hilit=Slide

Wideband tuning
viewtopic.php?f=5&t=18191

Also the ground strap is showing the plug may be too hot. It may be from your tune if it’s lean. If I were you I would run a br9es plug for now until you get a tune under control.

And chop that plug properly. Plugs are cheap. Pistons are not

Just skimmed through like page #3. Your cylinder clearance was way over. It’s supposed to be only like 4-7 thousandths. Also Your ring end gap was also about 5x over the service limit.

How many hours were on this Engine before this rebuild?

Hoser completely rebuilt Engine about April 2015,how many hours were on it I don’t know,but it did not get rode that much,I didn’t think there was enough run time on it for that much wear,I think I must have sucked up some sand or dirt to bring it a premature death.
Thanks

Also I am convinced there's something else going on.Pilot sat outside for 8 years under tarp before being rescued by the guy I bought it off of in California.He got it running again but didnt change piston or anything major,he didnt have it that long.I bought it,It ran like a bat out of hell(running uni straight off carb} I took whole Engine off and sent it to hoser to go thru,he did complete rebuild top to bottom.I get it back,install it,runs great,I build airbox for it,it runs great! NEVER CHANGED JETTING! Run it for 4 years like that no problems till it gives out at Little Sahara couple months ago{changed pipe month before LS with no jetting changes}

So now I'm back to original pipe,original carb,and its running like dog shit and I have to go down from a 170 jet to 142 and it still seems rich? And it's had this miss the whole time that it's never had before.I don't see how adding a little bit bigger airbox would change jetting that much or cause that miss,something else is going on

Check your reed petals, a small tear at the end of one will cause a rich condition.

Brand new reeds but I am going to pull them out and check again because something weird is happening.Talked to Socalgi yesterday,he suggested I call you to see if you could figure this thing out.
Is there anything electrical that would cause a miss at WOT (Wide Open Throttle)? Saturday{when running chinese pwk knckoff,}it would run great holding it steady at about 1/2 throttle,no miss.Yesterday with old carb I didnt get chance to do anything but a couple wide open runs briefly since I was at my house in subdivision.But miss only seems to happen at WOT (Wide Open Throttle)

I will PM you my number.

Is your CDI (Capacitor Discharge Ignition) modified for no rev limit?

Pretty sure it came that way,CDI (Capacitor Discharge Ignition) has somebody’s label on it,not stock

Well had breakthrough today but Pilot still not running right with this carb.
Got to leave Work early because the power went out.
Came home took carb off again and cleaned it again blowing compressed air through everything etc,put it back on with 175 jet,As scpilot confirmed my suspicions theres no way this carb should have to go down to 142 jet at sea level when it was running a 170 before.
So just like before pilot was bogging,plug wet and black

So here’s the breakthrough,and I don’t want to type it cause I can already hear CO telling me I told you so
So I’ve been meaning to do it,wanted to do it,but didn’t do it till today,which was testing the fuel pump.
So I took fuel hose going to carb off and put it in measuring cup,cranked Engine for 10 seconds and only got 2 ounces
Manual says take fuel line off T and put in cup and should get 4.7 ounces idling at 10 seconds,so I pull it off the T and put it in cup,start it and some starts to flow but I didn’t have stopwatch ready so I started again and nothing at all was flowing
https://youtu.be/HGy760Rh85c

So I take out fuel filter,and it’s embarrassing what I found.Cleaned the filter per Hosers instructions till I got it clean,as seen in pics

After I cleaned filter redid test with a lot better results but still not up to spec
With hose from carb about 3 ounces,with hose from T(from which I got nothing before) I got almost 4 ounces

Well honestly I think you may have found your problem.
Your pump is supplying inconsistent fuel supply.
No chance in hell you can jet a carb with an issue like that.
That's basically what has been happening to me lately.
I have now switched all of my machines to the electric pump that TerryH is running.
My brother and I are going for a ride tomorrow and then the next day I am going for a ride with my buddy who will be driving the death machine, which also now has an electric pump.
I will post a ride report soon.
Just my opinions.
CO

I thought about going to that,I’m hesitant though.Socalgi made me a good deal on a Pilot pump,if it doesn’t meet spec I can return it