Silencer Construction, for Plunger A10

[bikerjohndavies]

Hi Mike, in answer to your questions, as I understand it the pipe reduced to fit inside the silencer that was hollow and the reduced part was drilled with holes and the end plugged. The part numbers were 67-2770 (o/s) and 67-2771 (n/s) for the pipes and 67-2774 for the silencers. I believe that the C11 and C12 had a similar setup originally. I also believe that they looked exactly the same as the standard pipes but cannot be sure.

[limeyrob]

There's perforated stainless tube on e-bay, search "STAINLESS STEEL SILENCER PERFORATED BAFFLE TUBE 32MM TO 76MM ALL LENGTHS"
Looks like it has potential.  You could pack around it with rockwool as an absorber and if that wasn't enough weld a washer halfway along.
You could weld it to the exhaust and slip the silencer over the lot.

[Rex]

I would suggest it's not made permanent until it's been tried. It might make little difference noise-wise but a big difference to performance.
DAMHIKT.

[MikPowl]

Thanks, John, that's really useful. This is basically the same arrangement as the Velo baffle as mentioned by Joolstacho but achieved in a slightly different way, I think?  I'll check out the dimensions of the Velo item and if not suitable I'll get some piping that will fit inside and extend a standard Flash downpipe. Drilled and plugged, it'll be like the original.  I'd wondered if the baffle was plugged because a plug would provide the back pressure pulse that presumably would be needed for the more aggressive valve timing/overlap of the 356 cam.  Now it's back to the old question much depated on this site: 'Who makes pipes that fit properly?'!!   

[limeyrob]

I'd forgotten about Velo baffles, I seem to recall they can be made to fit but they are £28.  I don't think the end plate matters for the cam, there will be a "reflection" from the open tube end and our engines produce most power with open pipes.

[MikPowl]

Thanks, LimeyRob. Maybe an idea to make someting easily modded to try different baffles?

[Rex]

Another option would be to fit an after-market baffle intended for late model (Indian) Royal Enfields. Nicely made and inexpensive.