MCB claims Fett Reed spacers give the 2001 MXZ800 an etxtra horse for about $50.
* * Also, adds a total of 2.5HP when combined with the Carbon Tech Reed Petals, or 5hp when used with the V-Force Reeds. Not sure how accurate
* * these numbers are but check out the dyno graph below. How do these reed spacers actually work -- anyone know?
MXZ DYNO (http://www.mcbperformance.com/mxz800dyno.html)

Hey Blaise, talked with you last season some about Doo 800 twins. *Ended up trading my 01 in on an 02. *Someone hit me up in Quebec last spring. *Anyhow, have RKT head, spacers and boyesen reed petals. *Fett and Boyesens seem to improve throttle response, but I don't feel extra hp with them, just snappier. *Had Carbon Tech petals in for a short time. *They ended up cupping and ruining the bottom end of the throttle response. *Took out reed cages and the petals were up off the cages by a good 1/8"!! *Not impressed. *Just put in Thundershift arms and Cudneys' restrictor. *Will post results SUnday. *What are you running for pins?

Hey Paul, *I remember you. *How is everything? *How do you like that new 800?
Where do the reed spacers go? *After you install them do you have a hard time fitting *the air box back in its *tight spot? *
I am running 10.3g hollow pins with Cudney's *Thundershift Arm setup. *My sled rips with this setup. *I thought you had the Heelclickers?

Reed spacers come with a set of gaskets and long bolts. *Spacers go between case and reed cage, w/ gasket next to case. *Airbox takes a little more patience to put on, but no biggy. *Ran around yesterday to find Doo threaded pins. *Weighed them, 10.8g a piece. *Sled is beck together, and we're off to camp tonight. *Will give ya feedback Sunday eve. *As per forum talk here, I discovered that the Sled pro tool needed a .215 spacer. *Checked my alignment, and sure enough, out that much. *That should help a bunch. *Was pulling cords out of my last belt.

VTsleddr, are you sure the Carbon Techs were installed the right way? I just put a set in my Mach Z and the instructions said to make sure they are put in the right way because they come with a slight curve to them for better sealing.

yup, I double checked each one I put on, flipping them over and checking for flush. *Don't know why they fatigued so quickly.

Most of the time reed spacers are used to pull the reed assembly out of the engine uncovering more of the rear intake port of the clyinder. While you have your head off take a lite and check down inside that rear transfer port.You will see part of the reed stops partially covering the port. Spacing out the reed cage allows better flow up that port and into the combustion chamber, hense more HP,,, Quicker filling of the clyinder. Most V-Force systems make their reed cages to already do this and it does give them an advantage.On my FIII 6oo I had to make my own spacers to do this.. http://www.snowmobileworld.com/forums/iB_html/non-cgi/emoticons/smile.gif