Aprilia RS125 Two Stroke

Two Stroke on a budget – Aprilia RS125 (Part 10)

Two Stroke on a budget part 10 – Conclusion

So a few minor bits and pieces have been done – the second hand windscreen has been fitted as have the mirrors. With the carb cleaned again it’s not leaking fuel any more and it’s running really quite sweetly. I still think the bottom end is not quite as crisp as it could be but you have to rev these things to get anything out of them anyway.

I have to say I am amazed with how well this thing rides, it’s not surprising they have quite a cult following. The performance from the little Rotax is quite simply astonishing – at 30BHP that works out at 240bhp / litre, which is simply amazing. I don’t think I will ever tire of the power valve opening at about 6000 RPM and the noise and power delivery changing dramatically.

Here’s a photo of the bike as it stands now – I am still waiting for the seat to arrive and there are still a couple of minor bits to be fettled – front indicators might be a good idea and the horn isn’t working yet. Perhaps the biggest bit left is the fairing vee panel – the  side panels are off an RS50 and the vee is off the 125, they just don’t meet up properly. I have tried to get one but have not been able to so far. I will keep trying, one will turn up one day.

I think it’s looking pretty damn smart and I very much look forward to getting the seat and doing the finishing touches. It rides really well, it sounds superb, a very worthwhile project in my opinion.

Which brings me to the subject of the budget. Well, it cost a lot more than expected as these things so often do. Some of the parts were a lot harder to get than I thought they would be and most were a lot more expensive. These bikes were often owned by 17 year olds with massive egos and little experience so many got crashed and trashed. In one respect that’s a good thing for me as many parts are available but it’s also a bad thing when you come to look for body panels. You can get complete sets from China but at about £320-380 they are not in keeping with a budget build and being Chinese they are probably shit. Most of them only do the panels for the 2006 on model anyway. One surprise I had was the perception by many sellers of pars that their bits are worth a fortune. Every time I came to hunt for something items at on line auctions went for prices way lower than their buy it now counterparts. I still find that very odd, it doesn’t really happen with most other bikes. My total spend was way under £1,000 – Actually about £820 when allowing £120 for tyres that I haven’t got yet. I think that’s a hell of a lot of bike for the money. For it to be worth top money there are still a few things to sort. If I was to factor in the countless hours I have spent on it then it’s hard to see a commercial success but in terms of satisfaction I reckon it’s a winner.

The conclusion: At last places are opening up again now and that has allowed me to make some more progress. My seat is now back from being recovered and is looking absolutely splendid, many thanks to my neighbour Alison Tuck for a job well done. I fitted a pair of universal front indicators as I couldn’t find a pair of original ones in decent condition. The biggest job though was the tyres, the ones on there had loads of tread but both looked a wee bit manky, especially the front one. Those of you with long memories may recall that I got what was supposed too be a nearly new tyre when I replaced the rear wheel. On closer inspection I saw some cracks that suggested the tyre was older than I originally thought. A quick phone call to Julian at TyreDemon in Wainfleet and I got a great deal on two perfect tyres so it was a no brainer really. These bikes are stupid fast and hitting those sorts of speeds on dodgy tyres is taking things beyond exciting.

Aprilia RS125 Two Stroke Rear WheelTrouble is I don’t have a tyre changing machine and it was too late in the day to take my wheels and tyres to the usual place so I had to resort to the old stick it in a vice to break the bead and then use big screwdrivers to get the tyre of methodology. That’s when the swearing started. Again.

It was really hot and sweat was pouring from my laboured brow but eventually both tyres were off and the new ones put on. It is important to stress that bike tyres are usually directional so look for arrows moulded in to the rubber that show which way round the tyre must be fitted. Then remember that on the Aprilia the brake disc is on the right rather than the left. Install the tyre the wrong way round, burst in to tears, take it off again and put it back on with it on the right way round. Thank God I had beer to console me.

With all that done it was about 9PM and I was hurting thanks to an outbreak of sciatica. I locked up and went to sleep knowing that everything was hunky dory for the MoT the following day.

Thursday morning, the sun is shining, I have a spring in my step, what could possibly go wrong? A flat front, bloody, bleeding, sodding, arse headed front tyre – that’s what!

Aprilia RS125 Two Stroke Front MudguardI thought it was probably the valve but a quick application of soapy water quickly showed a leak from the bead. Oh shit! So I let the tyre down and saw the problem straight away, a bit of the plastic coating had come off from the inside of the wheel and lodged itself so the bead couldn’t seat correctly. With that cleaned up the tyre was pumped back up and the whole wheel sprayed with soapy water once more – great, no sign of bubbles this time so I loaded it in the van to take it back to Julian at J and B Motorcycles for him to cast his expert eye over.

Aprilia RS125 Two StrokeThe MoT went rather well and apart from a very slight leak of exhaust gasses at he head it passed. Very pleased indeed, I have ended up with a really nice looking bike that goes like stink and handles beautifully. I know it will never be the most reliable of things but as far as fun factor is concerned it’s unbeatable value for money.

I hope you have enjoyed following this series and that you join me for the next project. I shan’t tell you what it is yet but it might be one of Yamaha’s Performance Verified Stonkers 🙂


Article provided by David Powell of Boston Bike Bits.

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