SX/SXi/SXi Pro Has anyone ever modded their aluminum waterbox??

[Fenix169motox]

Hey guys was talkin with some rxp guys this weekend about how they have a waterbox mod where they cut it in half pull the plate out and put some more holes in the baffle to help exhaust excape, has ANYONE done this on a sxi pro? my 92 sx had a fiberglass one blow up and i put two more 2 inch holes in the baffle and it sure made a difference until it blew up again.

so yeah anyone know of the hot setup? i do know and understand what the waterbox is there for, fully.

 

[Fenix169motox]

so i modded it today, cut it apart at the weld seam. put 17 3/8ths" holes in the plate below the two main holes. then put a 1 3/8ths" hole kinda beside the two main holes and into the exit chamber. I have WAYYYYY more throttle response. and no its not loud. you can barely tell a difference. sitting in the water with me on it the exhaust doesnt fill up with water either, kinda my main concern was to keep water out and help exhaust leave.

 

[Thumper333f]

Any pics? I've been thinking about doing this myself just didn't have the cahones to just start cutting and drilling.

 

[Fenix169motox]

Yeah i took a few. I think if i were to change anything i did i would put more holes in the top and less in the bottom. The tone did change just a little. a tiny bit deeper. but the rear exit exhaust and the flapper you cant hear it.
here's the plate

Then here's the top hole, goes into the exit pipe. everything in there is aluminum and super easy to cut. i used a hole saw here.

and there's some aluminum welds! make sure what your welding is CLEAN!! stress on the clean! i ran into some garbage in my weld and it ruined the look of the top seam. holds pressure just looks horrid.

 

[Timmahoe]

What did you use to cut it apart?

 

[sportfish258]

Just curious why 17 3/8's holes and why 1 3/8 . Any reason or just a gut feeling . That is a good wield for dirty aluminum . I have thought about making my own box type thing . Back pressure is needed just wondering how to figure it.

 

[Fenix169motox]

Back pressure is NOT needed after the expansion chamber on a 2 cycle. but yeah for the 17 holes i marked 3 rows 1 inch apart and 1 inch away and didnt wanna go too big. i used the 1 3/8 because the other stock holes are about that big. I kinda wish i went bigger for more tone but i guess i have what i have now! its so snappy!

But timmahoe i used a cutoff wheel grinder to cut it.

Oh and for random info: you know the 4 allan screws that look like they might do something on the box? yeah there's nothing behind em lol its plugged off inside the box. i'm guessing its for more water if needed because it is 1/8 npt.