Silencers... silence.. but on in frame pipes ( dirtbikes, quads, sleds) the silencer acts as part of the stinger section, the stinger section acts as a bleed-off for back pressure. All the action has allready happend in the diffuser and baffle sections but without the correct length stinger to bleed off the pressure you will overheat, seize your engine, make very little power ect.
If you want to run without silencers you need drag pipes that are designed with the correct length stinger.
The book "two stroke performance tuning" by adam graham bell explains 2stroke expansion chambers very well... I highly recommend the book if you want to learn more about 2stokes, a bit out dated by todays standers but still tons of really useful info.
94' Wildcat mtn cat 700 efi. Pretty much stock.