SST Silencer on a Stock pipe

[MRKRacing125]

Well my friend had an extra sst silencer laying around in his shop. So I happily took it from him. Anyways, I put it on last night and the silencer wiggles around ALOT. It's is bolted on fine and tight, but wiggles by the rubber mount like it wont go with the stock silencer. Can I use this silencer on the stock pipe or do I need to put the stock silencer back on? Thanks

 

[fatty_k]

I belive the SST silencer is best used while partnered with the SST pipe for best performance. Maybe it also fits the best with the SST pipe or its just another case of the ill fitting FMF exhaust systems.

 

[marcusgunby]

FMF do have a slightly bigger bore than std so it wont fit correctly.

 

[MRKRacing125]

Marcus... so can I try and ride with it or should I take it off and put the stocker back on?

 

[marcusgunby]

What you can do it use a feeler guage as a packer between the exhuast and silencer-but a cheap set and cut off one of the fingers and wrap it around the exhaust before you slip the silencer on-use some silicon sealer as well to keep it all snug.

 

[steve125]

MRKRacing125 besides the fit problem Marcus is helping you with. The inner core diameter of the sst silencer is too large for the stock or a non sst pipe. The core size controlls the bleed timing of the exhaust gases. If your bike is a big bore it may help, but chances are you will loose power with the sst sliencer. Run a regular FMF or PC shorty, ive dynoed them on the stock pipe and they work just fine. :cool:

 

[marcusgunby]

Steve could you give me and other a lesson in this bleed timing as i dont know anything about it to be honest-also once you mentioned to me about tuned lengths of exhausts-how do i work the tuned length out?thanks marcus.

 

[steve125]

Marcus, the stinger that leads from the last cone in the expansion chamber includes the silencer also. It is simply a pressure-bleed resister, which prevents the free escape of exhaust gases from inside the expansion chamber and thereby creates a "backpressure" to enhance the port-plugging efforts of the wave reflected by the reverse-cone(last cone). This outlet is much more sensitive to diameter than length. There's just not much to gain here by going bigger in the core size of the silencer. It's best to just stick with the length of the silencer for minor tuning options. On the tuned length of the pipe, it's measured from the piston face to the assumed reflection point of the reverse cone, usually it's just past the mid point of that last cone. When i'm doing a quick check from one pipe to another that fits the same bike i measure with a tape from the pipes manifold down the outside center of the pipe and ending at the beginning of the stinger. I use this just as a rough idea to compare one pipe to another. The shorter pipe for more peak power and the longer pipe for less peak but more below peak. Of course the cone angles and the pipes diameter play just as important role as the tuned length.

 

[MRKRacing125]

Well, I figured out why it it was wobbling and it was because I didnt have a washer on the rubber mount by the silencer connection. I rode it today with it on, and it seems to helped alittle.