I have made some changes on this page to help things out a little so please re-read the entire page before continuing to the order page.
Thanks for all your orders, keeps me busy in my shop where I love to be...
3. Put your old silencer on a book so it lays flat. Put a long bolt through your mounting hole, mount is vertical. measure from flat to center of bolt..
4. The length of your spigot.--Please see the notes.
5. Measure spigot O.D. --This is an important step, see notes.. 
6. Spigot i.d.
7. o.d. of your tube.
Because so many pipe stingers are not parrallel with the bike we need some slop in the spigot to stinger fit in order to make the silencer a good parrellel fit..
You need to make these adjustments while you are measuring steps # 1-3. If the spigot is too tight in the stinger (step #5) or too long (step #4) then there is no " adjustment" when installing the silencer.
The stock Maico pipe is a good example of this and a tight fitting and or too long of a spigot in that pipe throws the silencer off about 3 degrees out of parallel with the bike.
So the engineers just made a sloppy fitting spigot on there steel silencers, adjusted the dimensions in steps 1-3 and you end up with a parallel silencer. We don't like a sloppy fit, but we do like a loose, snug fit. Some installation adjustments are always needed..
Using your old silencer to measure from, 
follow the numbered steps and look at the picture above and below which shows how far off the edge of the tube the mount makes contact with the frame tab. Always measure looking at the "rear" of the silencer, always hold your square against the side of the silencer that makes "contact" with the frame tab.
1.
Make sure your mount is vertical when measuring. I would call this dimension a "1/2" left".
Important notes
#4- Length of your spigot. The spigot needs to be at least a 1/4"-1/2" clear minimum from bottoming out in your stinger. For most applications a spigot length of 1 1/4" is good.
#5- This is the one dimension that we need to get closer than a tape measure using 1/16" scale. If your not sure how to measure or have the correct tool to measure with I am sure you must have a friend who can do it for you..
Some stock steel silencers were really sloppy fitting into the stinger, we can tighten this up if you want, but in order to do that I need exact dimensions. We want a "loose, snug" fit into the stinger..For proper fitting spigots we need about .030" clearance from the O.D. to the stinger and a spigot that is at least a 1/4"-1/2" clear from bottoming out so that it doesnt take all the adjustment out of the silencer to the frame tab fit.
Thoughts
I
will work with you on your dimensioning, and you can email me and get
advice. If you dont have an old silencer to use to measure with, email
me and we will figure it out.
