Hitchcocks Forum

Finally solved the missing piece in getting my old 612 that I re acquired back to peak performance. I was getting frustrated with it's lack of performance despite setting it up as it was when I owned it previousley. The missing piece - or should I say piece that had to be removed was the baffle in the goldie silencer. With the baffle fitted it felt pretty flat, take it out and there is a huge step change in performance. When I had it previousley the pipe had no baffle so it is now 100% back to how it was. Noise increase is not that much, but then again I always ride with ear plugs. Just need to get a few more miles on the new cylinder before I really let her rip - at least 500 miles I reckon.

You got me wondering what my 612 would sound like without the baffle so I just went downstairs to try it out.



Turns out, after 5 minutes with a screwdriver, not much different to how it was earlier today. That's because it's successfully annihalated 95% of the packing in the reverse cone mega all by itself in the 300 or so miles it's done since being built. There were a few strands of material trapped under the end and the rest was just a long perforated tube with a coil of wire loosely wrapped round it. I've taken it out.

Sounds like it has decided to remove the excess / unwanted materials itself let us know the result of any road test !!

My old BSA C15 (I owned this in 1973-5) was fitted with a 12 to 1 piston from a Triumph Trident, a grass track methanol cam, a high level exhaust and a reverse cone megaphone. The engine was rebuilt by Roy Pidcock, as a favour when he was East Midlands grass track champion. He had gone over to Weslake engines and I effectively got some parts that would have otherwise gone in his own grass track bike. The overlap on the cam allowed the engine to rev to about 9,000 rpm (tbh, it didn't last long though) and it used to throw out a blue blame on the over-run - which used to "happily occupy" the local police on night shift, who used it as an excuse to constantly pull me over to check my documents.

It used to blow the glass-fibre stuffing out of the megaphone every couple of hundred miles or so and then my old Mum told me she could hear the bike coming over the far hill about three miles away (helped her get the kettle on). I tried reinforcing the stuffing with steel wool. It lasted a bit longer but still blew out and the resulting firework show from the exhaust was even more impressive - sparklers!

My 350 now has a Hitchcock's "Goldie" exhaust. I first took off the highly restrictive Indian home market one and fitted a reverse cone megaphone, as above. Same thing happened, far too loud. The additional problem is that it sets off car alarms in cars parked outside the long terraced row of houses in the local village.

The Goldie is less restrictive but a bit less anti-social. The bolt holding the baffle has a tendency to loosen off - the bike sounds like the bottom end has gone when it does that. I haven't tried removing it as yet.