After Market Exhaust

[john durrill]

Does anyone have the stock length of the stinger on a 71 through 74 125 pipe?
we have one that looks like its shortened.
JOhn & Peter

 

[OUCWBOY]

John,
All four of the "STOCK" pipes I have are the same at 3 3/4" in stinger length. I  don't know how stock the pipes really are, but they look stock.
Donny

[john durrill]

Thanks Donny. the one on the pipe i have had an after market scilencer and was 5 and 1/2 inches long. guess it let the scilencer move back enough to fit the rear mounting bracket.
John

 

[metalkfab]

'72 pipes had the open can silencer with a seperate baffle inside and no fiberglass packing.'74 pipes have a 2-hole silencer with the male end conical in shape and fiberglass packing .We have found '74 pipes for 100,125 and 175's to have a perforated stinger 7" lg.Some pipes have had the packing fill the whole tube area,others had just enough to cover the stinger.The pipes that had excessive packing ALL suffered from rusting on the bottom due to moisture in the packing.It rotted not only the outer shields but the inner chamber cone as well.If your going to keep that Penton,Change The Packing.P.S. If your stinger is perforated don't run without packing,the stinger can split open and you have to cut the shield off to properly replace the stinger.OH!By the way Al Buehner sells packing and other exhaust parts to bring things pack up to snuff.

[john durrill]

Thanks Metal,
 The 77 , 175 pipe had a 7 inch perforated stinger and packing. so it looks like 7 inches is a good # for 125 / 175's. on the packing , if the bike was jetted with packing in you need to keep it. it will loose some bottom end power if the packing is not in place.
 We found that on KTMs up all the way to my 79 400.
John & Peter

[john durrill]

Folks ,
I found this old post that covered some of the information. 7 inches looks like what Karl made up for the repop exhaust repair kits. The original stinger ID would be a good thing to know for me though. We could increase the Trapp perforated stinger in size enough that it will not effect the real stinger size. The real stinger we want to slide in as far as possible and still mount the Trapp on. The closer we get to the straight section of the pipe with the stinger the quieter the pipe and Trapp will be.  Does anyone have one they could look at and measure?
John D.