One way to overcome this is to either make a carb spacer block or a longer manifold. The longer intake path makes for a higher gas speed and can neutralise the reversion but going to long can cause a lag effect similar to turbo lag
Spot on .... That's one of the main mods that were done to worked XR75's ... Anti reversion steps also help .... Going too long is similar to going too big in volume and causes hesitation or delayed reaction when you hit the throttle .... and also when you back off and throttle on again ....
I also meant to say something like fiddy@norway is saying .... an engine with a high overlap cam will suffer from reversion at low revs / high load like trail plonking .... a stepped header pipe or a pipe like the Power/Mega Bomb might help .... but the real problem is the lobe separation on the cam .... With YZF's (DOHC) you can move one of the cams over 1 tooth to give the same lobe separation as the WRF's for increased bottom end power but you lose some of the "hit" and peak power .... With a Unicam engine you could advance the cam to improve bottom end power but you'd have to check your piston to valve clearances....
Advancing Intake and Exhaust : This will provide the car with more bottom end power, and will decrease top end. Advancing both cam gears will move overlap earlier but will not increase it.
Retarding Intake and Exhaust : This will increase the top end, but will decrease low end. Retarding both cam gears will move the overlap later and but will not change the amount of overlap.
Advance Exhaust Only : This will help the top end, and it reduces overlap.
Retard Exhaust only : This will help the mid range power, very useful for cars with big turbos / big cams. By increasing overlap, It decreases lag significantly. Doing this will bring the boost on all at once. Very common DSM modification.
Advance Intake only : This will increase overlap and helps the bottom end and mid range power. This mod will bring the turbo on all at once, although isnt a very common mod for DSMS.