The Xt400 side car (winter project)

Thank you guys for the complements. I am pleased with how it turned out. I got most of the setup bugs worked out. I took my son on his first ride today! We went about 18 miles of back/dirt roads. It was fun. He loved every minute of it. Although he did fall asleep for awhile. I guess the suspension must be working pretty well. haha I do have a video of the bike before paint. I will post some new pics/vids soon

I have modded my exhaust 3 times already,Im happy with it as a street setup now but would love to have modded for off road use.Dont have any of pipe bending tools or welder nor any buddies that have one so I guess Im sol.Since I put the harley mufflers on it has great sound and obnoxiously loud either.I dont have a way of making a sound clip at this time but when I can I will.
I know this has been discussed a million times before....I think I even have a thread on it, but I need help diagnosing my bikes condition. If this thread makes you angry or have the strong urge to tell me to use the search button...please save your strength and hot the little red "x" in the top right hand corner of your screen. If you are feeling in a good mood and want to help me out then thank you VERY much. I have read every carb thread on here and I am still slightly confused. I have vm30's on my 82' xs400. Right now I am running 150 mains and 40 pilots. i'm on the middle needle clip.
Here are my symptoms.

It runs good all the way up to about 3/4 throttle then if you give it WOT it cuts out and slows down. If I don't let off the throttle it will keep losing speed/rpms until I let off. As soon as I start to let off I get a burst of power. From what I have read this means it is to rich on top.....right? Here are what my plugs look like. Thanks for any and all help. Let me know if you need more info. Thanks.

Yup, that would be my diagnosis! I'd suggest going down 1 or 2 sizes on the mains, and see how she runs.

Scratch that! It is running lean if it is misfiring/surging at WOT and picks-up when you close the throttle a bit. Darn it! My brain isn't working too well at 01:30... :doh:

FYI, I've also found that "velocity stacks" between the pod filters and stock carbs also made a big difference in overall performance. Smoother, less noise, etc. I made mine 60mm long, to match the length of the factory rubber boots that attached to the airbox - DOHC engine, SOHC may be different length. Don't know if your carbs will respond like the stock carbs did... But it might be worth a try.
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My thought would be to go back 1 jet size and put the needle back in the stock position.By the color of the plugs looks like you are running just tad bit rich..Im throwing a guess out there but thats what I would try.I have read if you have a miss its running rich.Also how many turns do you have your air fuel mix at?Try going back to 2 3/4 and slowly opening them more till you get your engine to run smooth.One last thing did you sysnc the carbs?
Awesome rig! I grew up in north central PA. Love seeing the mountains in the background of your pics. I lived in Watsontown near the Susquehanna.
Awesome work man. Ive been wanting to sidecar the CBR for some time now. If I pickup another sportbike (was my plans this weekend original) ill probably go ahead and start working on it. And now ive got your design to base mine off of. :thumbsup:
Im wondering something since the bike has been converted to motocross style have you taken off road and how does the 4 stroke engine perform?Does it put out enough rpms for offroad riding?