Scooter Boy Tales
Another story of misdemeanours and clueless scooter tinkering from the halcyon days of the 80s.
My best mate had just bought his first scooter, an old N-reg Jet 200, you know… the usual 200cc registered as a 125, no MOT, insurance etc. None of that was necessary to us; what was important was getting it on the road. They were strange machines those Jets, a bit like the leftover’s from the Innocenti factory cobbled together in Spain to make a few extra quid. He only lived four doors down so a new scooter on the block had to be checked out.
It was a clean tidy machine, even though it had the obligatory oddball 1980s paint scheme. A sort of blue in most places with lighter shades here and there, white forks and wheels, a bright red fresco and for some reason a red oxide primer front mudguard that no matter how much you painted it the red still showed through afterwards. Up till now, his two-wheeled exploits had got as far as going up and down the garden path on his old man’s chicken chaser. This had come to an abrupt end after wedging it upright in next door’s fence trying to pull a wheelie, so the extra power of the 200cc Jet seemed like it might be too much to handle.
It wasn’t though. The Jet, for some reason, had the power of a gnat. It made the chicken chaser seem like a MotoGP bike in comparison, signalling there was something wrong in the engine department. Furthermore, there was the problem of getting it started. According to the manual: “Two or three prods of the kickstart pedal and it will start.” Two or three on this Jet though meant two or three hundred and even then it was struggling. Something else that suggested there might be a problem was the fact you could push the kickstart all the way to the floor with just your hand. Using the knowledge we had acquired it was decided that the engine was lacking compression, hence the starting problems. The simple solution was to strip down the top end and see exactly what was wrong. Rather than take the easy route of removing the rear shock absorber it was decided to go the whole shebang and completely remove the engine. I was impressed, no one had dared take the engine out of the frame before… not round our neck of the woods anyway. Several hours later and hey presto, one grubby and rather tired-looking Lambretta motor lay strewn across the patio.
For a while, we just stared at it, looking rather bemused. “Go on then, take the top end off and see what’s wrong.” Manual in one hand, spanner in the other slowly each nut and bolt was undone until the cylinder was removed. There was enough carbon in there to start your own coking
It was decided to go the whole shebang and remove the engine. I was impressed, no one had dared take the engine out of the frame before… not round our neck of the woods.
plant and the exhaust port? Well, let’s just say it was about 10 times smaller than it should have been. According to the manual, it was best to check the ring gap which should be measured in thousandths of an inch with a feeler gauge. We needed one that measured in thousandths of a yard judging by the enormity of the gap. It didn’t much help that you could see clear daylight between the piston and the bore either.
Having worked out that a re-bore was needed, we trudged off to the local scooter shop to get it sorted. The man behind the counter looked at it and quietly laughed to himself. Who could blame him? “Yes, it wants a re-bore alright and I have just the piston. He produced an old box with GPM written on the side of it. “This is a special racing one with a Dykes ring at the top.” Anything with racing in sounded good to us, even though we didn’t have a clue what he was on about.
A week or so later and the re-bore was back. My mate was eager to put it all back together and I was ready to help. By chance, I wasn’t available for the big moment but reminded him that the arrow on the piston must face downwards. He asked why that was so and I replied: “I don’t know but if you don’t then the engine can blow up. Something to do with the piston rings.”
He promised to adhere to the instructions and sailed ahead at full steam into the rebuild. I turned up just as he was about to fire it up with everything bolted in. It was a remarkable achievement, even more so because he had used his dad’s imperial spanners – you know, the ones that fit almost… but not quite. Fuel on and third kick it burst into life, having never done that previously. Standing there with a grin on his face he blipped the throttle several times until there was an almighty bang. The ground shook around us as the engine came to an abrupt halt. Elation had turned to desperation all in one turn of the throttle – but what the hell had happened?
An inquest was opened as we feverishly stripped the top end down. With the cylinder head removed it exposed the piston, well... what was left of it anyway! Most of the whole bottom half had gone, presumably disappearing down the exhaust port when the piston ring had caught it. Upon closer inspection it was noted that the arrow on the piston was pointing upwards not down as instructed.
Assuring me that piston was facing downwards when it was fitted was all well said and good, but what he had failed to realise was that the engine was upside down on the bench when it was being rebuilt! Unbelievable! Another harsh lesson learned in our early days of scooter ownership!