Making a Shorty Muffler

[cujokiller]

In the plan of revamping the look of my 500, I am thinking about shortening the muffler by 5 inches.  I was wondering if anybody has tried this.  If so, how did it affect the performance.  If no one has tried this hopefully I will finish the muffler today.  Any help would be appreciated.  And Thanks to everyone that has helped me so far by giving me info on stuff to do.

                                                                                 Justin

[Spider]

This is a pic from Doordie's album If you do a search for his posts you will find a wealth of information and explaination.

Dale

[cujokiller]

i appreciate it.

                                   Justin

[gowen]

as for performance loss, you will lose quite an amount of top-end power as back pressure will be lost.

[cujokiller]

Well, I completed the silencer today.  I didn't loose too much top end.  I mainly ride with a 250s and it worked out great.  Sounds alot better also.

                                                                 Justin

[doordie]

The best power is without any muffler or as short as possible in any case,BUT you have too have right dimension/length for stingerpipe(last pipe before muffler).
If you shorten muffler, it?s possible to reduce area of stinger (or add lenght to it).
Buy beware of to tight/long stinger,a hole in piston can be fast result!

The "pipe guy" is MUN in this forum!

The pic shows a special stinger 

[kx666]

it is all about finding the happy medium. there is no "free ride" if you give some where you had to take from some where.
 
but i have found the k5 loves the short silencer, it is just loud as hell (a good thing when no one is around, but a bad thing when there are tree huggers around)

[cujokiller]

Luckily there are no trees in El Paso so they are no where around. 

[kx666]

ok...what do granolas' hug?
...cacti?

[mun]

I agree once again with doordie. If you lost power when you shorten muffler, so you can make stinger of smaller diam. pipe, or make stinger longer. There is yet one possibility: make reducing socket to beginning of stinger.
http://img201.imageshack.us/my.php?image=hondars125stingerka2.jpg

Thanks doordie, but please, don't call me "pipe guy", rather "washer man". "Put washer beginning of pipe" and "put washer beginning of stinger" ... 
There are many who know lot of KX500 pipe, lot more than me. Together we know almost all needed.

[kx666]

I agree once again with doordie. If you lost power when you shorten muffler, so you can make stinger of smaller diam. pipe, or make stinger longer. There is yet one possibility: make reducing socket to beginning of stinger.
http://img201.imageshack.us/my.php?image=hondars125stingerka2.jpg

Thanks doordie, but please, don't call me "pipe guy", rather "washer man". "Put washer beginning of pipe" and "put washer beginning of stinger" ... 
There are many who know lot of KX500 pipe, lot more than me. Together we know almost all needed.

wouldn't this be putting the same back pressure as if there was the full lenth silencer, basicly gaining noise ( ) and droping a few lbs?
the stinger is already relly long, i am not sure i am following you Mun what resorces have you found useful for 2 stroke exhaust?
~steve

[mun]

~steve.
 Yes.
Stinger's job is to keep proper pressure in pipe. It's also good to be long enought, that shock wave not ended too soon. If back pressure is too low you lost little bit power. If back pressure is too high you get little more power, but your engine going hotter and hotter and start knocking. You must retard ignition or lower compression.

Is this importing in 500cc motocross bike? 125cc World Champion RR-bike is different thing. They have fully programmable ignition with data acquisition. Cylinder head exchangeable with combustion chamber. Then you can once in a blue moon play with back pressure, "put washer beginning of stinger". This is my 2 cent.

I have made only one exhaust pipe (to my old "RR-KX"), so i'm not some pipe guru. I hope that i could make some other pipes, but seem quite bad.

MuN

PS. Couple years ago my wife want water to backyard. I draw through two wall about 8m long and 8mm diam. copper pipe from garage to backyard. Water coming like my piss (old man) . I changed pipeline from 8mm to 10mm and now water have pressure and coming fine. Note! The short output in garage is still 8mm! ("put washer beginning of stinger")

[cujokiller]

Thanks for all the help.  I made the shorty and I gained low-end but lost some top-end.  I forgot my camera to take some pics.  I will be sure to post some pics when I remember my camera to take the pics.   

                                                                            Justin