As far as I was concerned this bike bike was un-rideable as i have said . The only person who continued riding this bike was Martin Lampkin. I still have this bike, though back in the workshop here you can see the difference in some engine parts between the Lampkin bike and the standard bike. I am restoring the Martin Lampkin bike at the moment and will soon be sending off the cylinder for repainting. I have managed to find a piston which was quite difficult. The piston is the same size but the stroke is longer here on the barrel, you can see where it is written 166 mart. This barrel has the inlet port squared off .
So who would have carried out these modifications?
That would have been carried out in the factory. I know this because I have 2 bikes with exactly the same modification. One is my motorcycle and the other is the Martin Lampkin bike I'm restoring. I also have a spare engine.
It looks to have been closed in on both sides is that right?
Well, what they have done to the inlet port is square it off.
What would that have done to the power?
Well, if you imagine that this is a piston skirt by this inlet port, now you can see the piston going down, closing the port that one closes. The port gradually, because of the angle of the port and machining makes it closed slowly slowly slowly. Where on this bike it closes immediately, this one closes it with instant closure rather like a shutter in a camera.
Well, if you imagine that this is a piston skirt by this inlet port, now you can see the piston going down, closing the port that one closes. The port gradually, because of the angle of the port and machining makes it closed slowly slowly slowly. Where on this bike it closes immediately, this one closes it with instant closure rather like a shutter in a camera.
The rounded 1 may leak back a little bit. The squared off exhaust port acts more like a reed valve. This was a discovery that Bultaco made around late 1975, early 1976, because the first inlet port I had on my 326 bike, I think was in late 1975, this cylinder is a 1978 cylinder but because this particular bike never went into production, they were using and Alpina cylinder and modifying the inlet port.
This is a model 166, if you look up through the barrel of this Alpina 350 which is actually a 348cc, that's because the normal stroke on a 326 is 60 stroke and 82.3mm bore. The 348 is 64mm by 83.2. Lampkin went beyond that in, I am guessing 1979, when he went for 64 x 85 which = 363cc which is what is known as the jumbo.
I have never in my life or at least I don't remember, ever riding it. I have built one before as a replica which I mentioned before. I had a sidecar attached to it. I built this new bike out of bits and just for fun. I made one of these 363 cc engines, the big engine suited the sidecar very well but I don't know what else it might suit hahaha, because it is un-rideable, it is too powerful and a monster.