I'm 165, maybe 185 in gear. Bike is a KX 100 so fairly light maybe 160lbs. Issue is loosing the front when pushed. Can't seem to get tires past about 130 degrees. I have been riding it foot out style mainly due to bike size limiting my mobility. I will adjust that a bit and adopt a bit more knee out weight forward style to try and load the front. All of the crashes have been front end crashes at what I would consider an okay pace.
Short of lowering the forks not much I haven't tried with ride height. I've tried a range of springs from very soft to hard. Finally opted for cartridges which allowed me control of compression and rebound seperatelay to try and use rebound too keep front end down lower in the stroke.
This has been promising. Worked on it towards the end of the day and it helped with the front feeling more planted. I will need to work on this more. Problem tends to be ergonomic though.
Definitely start with adjusting the forks in the trees and get your body up over the front. Also keep in mind that you'll never get the bike setup as well as a sport bike. All that being said, in terms of slicks I went to a GP rear on the front on both bikes. I've been told its wrong but for me it just works.
I've got the forks as high as I can get them, they are hitting the bars. I will have to get more creative.
I have tried both Dulops and Bridgestones on my crf150r and like the Dunlops better, they are much better when cold. I run about 20psi!
My CRF150 is stock height in the rear and the forks are about 2 inches up in the front triple. BBR springs, revalved by Litz. It handles great road race style. I can lean it over till the pegs drag and that is a long way on a dirtbike.
On my bike I have a spacer to raise the bars so I could bring he forks up more. The suspension has full travel cause I also ride the dirt on the same bike with the forks in the correct place.
I'm hoping to find some take offs to try, both Pirelli and Dunlops. Handle bar spacers are a good idea, I'll give them a try. I too want to retain full travel.
https://www.flickr.com/photos/98577932@N00/15677534485/ Not the best photo but you can see what is going on!
I know it sounds strange but I run a mountain bike handlebar on my XR. It is a HD bar that is a 1/4 inch thick walled tube. The rise is only 1 inch. I found having my grips really low helped me keep my body forward and the front planted.
https://www.flickr.com/photos/98577932@N00/4817761323/ Here is Teddy (Apex/STT head chef) rocking it with clip-ons.
The rule in the class I run says your grips have to be above the top triple and you have to use stock mounting points. That is why I went with the real low rise Downhill mountain bike bar. Can't really see the bar, but you can see how low the grips are.
You can reduce fork length internally without changing useable travel. I've done it on a few dirt forks for customers that ran into the same issue you're having.
It has been my experience that if you can get your hands lower (low bar position) it effects the handling of these small bikes more then getting the forks lower. I would put the lowest, flattest bars I could if you have to run risers.