Took the cap of my exhaust this weekend - bike now sounds like a thumper (not too much noise !) - How much power does one lose with the spark arrestor ? - is there an alternative cap one can get for this exhaust, or does one just knock out the arrestor

Alan - DRZ400S

Look under the other Mods section to this forum where I tell of what I did to my exhast
end cap. Works great not to loud either. Adds
about 4 h.p. after removing air box lid and
re-jetting to a 165. O.k. I'll save some searching. Cut the solid end cap off the spark arrestor then added a 1 1/2" dia. sleeve so I could re-fasten it if I were to
still ride in the woods, then took a 1 3/8"
dia. holesaw to the exhaust tip end and opened it up. note the holesaw will slip right inside and be guided while drilling it
out. This really makes it breath in mid and mainly on top end. visit www.mcnews.com.au
under the tests section they give some Dyno
figures.

Thanks for the info, now if you can just give me those metric measurements I can be on my way - in millimeters please. Also if you can get a close up pick to Bryan, I am sure he would post it in the pictures section - yes we all would like to see what you have done.

Sorry, 1 3/8" dia. holesaw = 35mm dia.
1 1/2" dia/ sleeve = 38mm Dia.x about 50mm lg
Working on getting a digital camera to send
some pictures soon.

Come on borsy! Get a digital camera and send me some pictures QUICK! ! ! !

I have a Toshiba and love it. It's great to be able to take a picture of a bike part or a kid and send it out via e-mail or internet in only minutes.

This site needs LOTS of pictures (Alan sent me another and I still have to post it). But, remember we need some action pics too. Wheelie pictures are great and so are jumping pictures. Even if they've been digitally enhanced to make it look like bigger air. No problem!

Then there is the most coveted picture of all: Front wheel stand picture! But, I won't be doing that photo op.

Bryan...

Ordered the digital camera, pictures in a few days, but really a simple mod. take the end cap off. you will see the spark arrestor screen till it goes into a solid plug or cap
I used a dremmel tool with cut-off wheel and cut the solid end off its about an 1" off the end off the spark arrestor.
There are 3 steel ribs inside the arrestor supporting the screen.I think its hardened steel so thats why I used a cut-off wheel.
Where that meets the solid end plug thats where you cut it. go another 1/4 to 1/2" extra torward the screen or exhaust exit. I then made (found a sleeve) that fits inside
both the screen portion and the now lose piece end cap that was just cut away.The sleeve is about 1 1/2" dia, x 1 1/4"Long
it is very thin wall tubing about .06 or 1/16" thick. just enough to hold the self-tapping sheet metal screws #8's you'll
need 6, 3 to fasten the sleeve inside the
arrestor screen use the 3 steel ribs to tap
into as well, the ribs and screen should slide over the new inserted sleeve, drill the
3 holes and add screws.oh yeah don't forget to leave about 1/2" of the sleeve hanging out
thats what will be slipping into the loose piece end cap that was cut off. Then you drill and screw that. now you can leave it in place for woods riding or take the cap off for some closed course fun, I also used a 1-3/8" or 35mm bi-metal hole saw to open up
the size of the exhaut tip end. it fits nicely inside the tip and is well guided while drilling it out. do this with the cap
fastened on the exhaust pipe much easier to hold. when finished take out the slug (da !!)
and re-jet I ended up with a 165 main with airbox lid off. I also am running 93 octaine
might try a 170 main and 48 pilot. but this
thing moves out and sounds great not loud at all but now at least like a thumper. You will really notice improvement in mid and mostly on top end. You can always add packing around
the outside of the arrestor screen if it may be to loud for you.and you can always add the
solid end cap back on when woods riding on state forests etc. you won't be dissapointed.
Brian your right a picture would have said it all, man I have finger cramps. but thanks for
a great site !!!!!

Bryan - Which model Toshiba Digital camera are you using?

Rich