Saturday 8 May 2021

Yamaha AS3

I acquired my favourite bike of all time (I’m 37 this year) toward the end of June in 1975. A 125cc two stroke twin, adjustable rear shocks, steering damper, TLS front brake, silk smooth clutch, enough power in first gear to see off almost anything at the traffic lights - what more could anyone want? Well, it was a thousand percent better than the D7 Bantam I traded in anyway.

It wasn’t until I arrived home that I noticed the non-matching silencers... I’d taken my elder brother with me to check over the machine; I’d listened long and patiently while he explained the reasons why I shouldn’t buy the bike and then handed over 180 notes (several months pay).

After a bit of tuning with the aid of an old manual, I got all togged up to see what it would do. Save for ownership of a Honda C95E (150cc) twin, I was used to things like Bantams that if they reached seven thousand revs without exploding you considered yourself very lucky indeed; imagine my surprise then as the Yam’s rev counter crept up from nine to ten, eleven, twelve thousand with thirteen and fourteen in the red sector still to go. With a bit of wind behind me the speedo read an optimistic 83mph.

This was the first bike to give a great pride of ownership, never before had I been one for regular polishing and washing - trying to maintain the bike’s good looks, not to maintain its value, just because I liked the bike so much. After the best part of a years enjoyable riding, a lot of top end rattle began to intrude upon my happiness. I took the head and barrels off, finding the big and small ends in excellent condition despite the number of times I played with the five speed gearbox, there were no signs of seizure thanks to the autolube direct oiling system and after I’d measured the bore and ring wear I realised it was a borderline case - as I had the cash I decided a re-bore was in order.

This was a very bad decision for me as I’m sure the bike would have kept going for many thousands of miles if I’d left well alone. Borrowing my brother’s D10/14 (we never did find out which it was) I took the barrels to a Yamaha dealer to be re-bored. A short, heavy shower left the road greasy, going around an adverse camber corner at 50mph, the Bantam simply slid from under me. Sailing, as if in slow motion, through the air, I was enthralled as the bike bounced down the road, sometimes bucking as if it would break at the headstock in two separate bits, occasionally sending up tiny showers of sparks. I then passed out as four cars almost ran me over. I awoke to find someone tugging at my helmet and a searing pain from my shoulder.

Being self employed I lost my income as my broken collar bone took eight weeks to mend, by which time the barrels were ready to fit. Unfortunately, I had been supplied with two pistons with different part numbers. It took three weeks for them to be re-ordered and then they were the wrong ones again. The third set arrived a further three weeks later, by which time my enthusiasm for the rebuild was half hearted, not helped by the fact that I couldn’t really afford to do it any more. The barrels were bevelled at the bottom so the pistons and rings went in very easily. The bike was ready to go in a few hours, which is one of the reasons why I like the simplicity of two strokes.

I ran the bike in gently, although I now realise that I would probably been better off thrashing it in, as some say. It appeared gutless and faded very easily. Stripping it down again, the new pistons were slightly scuffed although the cross-hatch pattern on the bores was still quite plain to see. Testing the rings by the feeler gauge method showed that they were within a few thou of needing to be replaced. It was the first time I’d seen such well made rings, though, and the Teflon sort of microscopic covering (to assist the running in period, so I was told) seemed a marvellous idea.

I bought new pistons and rings, again, writing to Mitsui this time in an endeavour to obtain the right part number. Even with their reply in my hand, the storeman insisted that he was right and they were wrong. Finally, I had to order the wrong part numbers, which turned out to be the right parts. Fitting everything back together, I thrashed it in, this time to see if it made any difference. Not much, until I decoked the exhaust system, re-timed it properly, fitted new plugs, pumped up the tyres, adjusted the chain, etc., etc. - yes, that was more like it and the new pistons were probably not needed, as I found out later that the bikes run on very fine tolerances and the few thous I had left after the re-bore would have lasted for many thousands of miles.

I decided to use the bike for a 400 mile round trip to look up some mates, I was sure the bike would do the journey, no problem. The bike did about 80mpg at a constant 55mph, going any slower meant constant gear changing. On the M1 I got her up to an indicated eighty only to be flashed by a coach driver, he accelerated past in a cloud of stinking diesel fumes.


It wasn't a straightforward thrash, though, because the bike kept going off song or fading. I eventually pulled into a service area to check the engine. The motor was very hot, which I found out the hard way as I had to remove the engine cover to adjust the contact points - I had to adjust them three times on the journey up, realising that the felt heel was wearing rapidly due to lack of lubrication. Coming back, with the wind behind me, she absolutely flew along.

As time went by she began to take on a slightly tatty appearance, so I stripped her down completely, except for the engine. I repainted the frame with four coats of enamel by hand. I fitted two new tyres, a seat cover and a battery, giving all the parts a good clean before refitting, I also touched up areas on the tank, etc with the nearest colour I could obtain or redid the whole area. The chrome was OK and came up well with some Solvol. The bike looked as good if not better than new.

One day I was waiting to turn at a T junction when a woman just drove straight into me. She told me she had thought I’d already moved off. A new chrome mudguard, a headlamp, etc set her back quite a bit - she tried to get out of it by introducing me to her son-in-law who was a fireman. They eventually agreed that it was ’mostly’(!) her fault. She paid.

This incident was another nail in the coffin of my happy motorcycling future. I didn’t stop to think about it that way before, but it was always the other person’s fault, and it was beginning to become far too regular for my liking and I was becoming tired of that hoary old chestnut, I’m sorry, but I just didn’t see you.

I’d always been an all weather biker, but after passing my test I realised that I could drive a three wheeler legally. A young friend had been on at me for months to sell him the bike, which I did when I found what I thought was a bargain Reliant. I gave him the workshop manual with the bike, but it didn’t stop him constantly coming around asking me how to fix it and to help him with jobs on the bike.


He eventually stopped bothering me after I’d become fed up with him. The next time I saw him he was on a Bonnie that had been bored out to 750cc; he was complaining because no-one had mentioned the effect the increased stress would have on the main bearings. He eventually admitted that he had sold the Yam to pay for the conversion and that the new owner had immediately crashed the bike.

The new owner had been frightened. to come to see me as he knew how much I had liked the Yamaha yes, it’s a small tinny buzz box but it always started first kick, ran really well at times and was very good on petrol. I helped the lad rebuild the bike.
The forks had been straightened by an amateur engineer for a fiver, the baffles had been thrown away, there was rust everywhere, a massive oil leak from the rev counter drive that didn’t work and a general air of neglect.

When it was more or less back together I took it out for a spin. I could have cried, or else murdered its previous owners for what they had done to my bike. When the new owner asked my opinion of the bike, I told him that it was dangerous and illegal and that he’d have to spend money on new forks, silencers, etc., or get rid of the bike. It ended up stuck at the back of his shed for eighteen months until some scrap dealers called and threw it onto the back of their lorry.

David Dale