Main Motorcycle: 2001 Trophy 1200, T509
Join Date: Jul 2011
Location: NH USA
Other Motorcycle: Norton Commando MK 3
Extra Motorcycle: 1968 BSA Thunderbolt
Those allen heads are not stock, original ones were chromed button head and tack welded. Are you sure it's not a period Triumoh off road? They outwardly look identical except for the very end as look into the muffler. Also just forward of the lower spring see if it carries #2200512 and "not for road use". This is the muffler I am running and it's not too loud but it hasn't been f'd with either. If it is this one you probably could cut off the allen heads with a Dremel and re-pack. If it was originaly the "quiet" one, well they have internal chambers and baffles to make them quiet and don't rely on fibre glass. So if the previous owner just some how gutted it or willy nilly just drilled through all the innards, you my friend may be screwed.