Model 91 Sherpa T - Exhaust System

[twistedleader]

All
My brother and I have a Model 91 Sherpa (Matching numbers 9100594) in the shed at home. Bit rough but complete which we will restore one day.
My question is that all of the photos I can find of the 91 model show the large/long one piece muffler and spark arrestor whereas ours has the smaller separate triangular spark arrestor which I have always associated with the Model 80.
It is definitely original as I know the bikes history.
I know Bultaco swapped and changed parts and made many changes within models but can anyone shed any light on this.
Thanks and kind regards... David

[Guy53]

That can be different in Australia, but when I worked at a moto dealership in 74/75 ... We where a Yamaha dealer and also a Bultaco dealer. I had the same question about 2 Alpina 1974 that did not shared all the same parts ( muffler and gas cap ). The answer of the Canadian distributor was : " Since the Bultaco company is alsways improving there products, they often don't wait for the next model to make minor change ". I had to take a deep breath and keep the gas thank with the small opening and the small triangular spark arrestor that was quickly bloked by oïl residue.

Guy

[sherpa]

Models 91/92 had the triangular rear muffler. The 'banana' rear muffler was introduced in 1974 on the M124 / M125. The 'clubfoot' was introduced late 1974 on the M150 / M151and these were the last of the slimline tank & seat setup.
Cheers Greg

[twistedleader]

Thanks for your info, Greg and Guy.
David

[sherpa]

The problem is that the triangular muffler is very restrictive and robs the bike of power. Back in the day everyone ran their bikes without it, however the bikes are quite noisy and I don't think you would get away with it these days. Which is probably why you see lots of 91/92 bikes fitted with later rear mufflers.
Greg

[twistedleader]

Greg
Your absolutely right, on both of my Sherpas back in the 70's, a 250 and a 326 I took off (and threw away) the triangular muffler.
I also did the same to two Alpinas my brother and I owned.
Kind regards... David

[Guy53]

In every dirt magazine, they explained the problem and suggested that you made a tube ( I don't remember the diameter ) with both end curved the oposite way and put a muffler/spark arrestor at the end that you would tie at the top where the seat ( Alpina ) was bolted to the frame.

Guy