Hi all. Can someone tell me if the back box on a 349 (year around 1980?) is the only part that needs a decoke? That flattened part of the exhaust under the tank, does that contain baffles too? How would both be done? Bike starts and idles great after a thorough carb clean and rebuild, but feels like the baffles are blocked on wide throttle openings. I've done the caustic soak and a blowtorch up it's back box, but I'm still having an issue when get on the power. 

Edited September 25, 20205 yr by Waynetod

The bit under the tank is comprised of a perforated tube with packing round it. Cleaning and repacking is well worth doing. Cut a window in the back of the box so the repair doesn't show.

Thanks for the reply. Will look into cutting it open. 

Cut the back of both my 348 silencers open, packing was shot & full of old oil, i used a blow torch after removing packing and burnt the insides clean and dry then re-packed and then cut over size tin plates which i riveted on ?

On 9/26/2020 at 11:12 AM, sparkieb said:

Cut the back of both my 348 silencers open, packing was shot & full of old oil, i used a blow torch after removing packing and burnt the insides clean and dry then re-packed and then cut over size tin plates which i riveted on ?

Was it running crap on wider throttle openings before you cut them open, and was it running better afterwards? 

Was a non runner, it was all part of the restoration. But now its all finished it does run as sweet as a nut ?