Bultaco clubfoot muffler
Posted: Sun Nov 16, 2025 10:27 am
In about 1974, 
introduced their "Clubfoot" muffler on Sherpa Ts and Alpinas, replacing the "Banana" type and earlier "Triangle" type.
The Clubfoot is a fairly weird design and quite heavy but does make for a very quiet exhaust and incorporates a spark arrestor, which was a thing back then if you wanted to ride your bike in some states of the US. Motorbike noise was a thing everywhere.
I acquired a well-used clubfoot muffler for my model 138 (350cc) Alpina about 25 years ago in a parts swap deal. I restored the Alpina and rode it since then and despite fitting a new carburettor, it never ran that well at low throttle openings. On a ride at VMX Classic Dirt 18 a few weeks ago, the exhaust started rattling quite badly.
I thought the rattle was the perforated tube in the main muffler moving or fallen apart, but it turns out it was the perforated tube inside the Clubfoot muffler had broken off at the front end and was causing havoc inside the muffler. There was no packing left in there. The foot section has mechanical baffling which was all intact so I only had to fix the inlet section that has the perf tube.
The photo shows the new piece of perforated tube I put in, before repacking it with mineral fibre.
I went for a decent test ride yesterday and am pleased to report that the exhaust is much quieter, doesn't rattle and the motor runs beautifully smoothly at all throttle openings so I'm very happy with the result.
I wasn't surprised at the improvement in how it ran because it's well known that the bigger Sherpa T and Alpina motors are quite sensitive to the condition of the packing in the main muffler.
As you can probably tell, that Clubfoot muffler had been worked on a few times before it came to me.
introduced their "Clubfoot" muffler on Sherpa Ts and Alpinas, replacing the "Banana" type and earlier "Triangle" type.The Clubfoot is a fairly weird design and quite heavy but does make for a very quiet exhaust and incorporates a spark arrestor, which was a thing back then if you wanted to ride your bike in some states of the US. Motorbike noise was a thing everywhere.
I acquired a well-used clubfoot muffler for my model 138 (350cc)
Alpina about 25 years ago in a parts swap deal. I restored the Alpina and rode it since then and despite fitting a new carburettor, it never ran that well at low throttle openings. On a ride at VMX Classic Dirt 18 a few weeks ago, the exhaust started rattling quite badly.I thought the rattle was the perforated tube in the main muffler moving or fallen apart, but it turns out it was the perforated tube inside the Clubfoot muffler had broken off at the front end and was causing havoc inside the muffler. There was no packing left in there. The foot section has mechanical baffling which was all intact so I only had to fix the inlet section that has the perf tube.
The photo shows the new piece of perforated tube I put in, before repacking it with mineral fibre.
I went for a decent test ride yesterday and am pleased to report that the exhaust is much quieter, doesn't rattle and the motor runs beautifully smoothly at all throttle openings so I'm very happy with the result.
I wasn't surprised at the improvement in how it ran because it's well known that the bigger
Sherpa T and Alpina motors are quite sensitive to the condition of the packing in the main muffler.As you can probably tell, that Clubfoot muffler had been worked on a few times before it came to me.