Aprilia RS125 restoration

Two Stroke on a budget – Aprilia RS125 (Part 3)

Two stroke on the cheap – Aprilia RS125 Part three. Will she live?

Ok, with the Aprilia back home I realised that I had nowhere to put it, a significant reorganisation of the store rooms and workshop were well overdue so it would have to live on the van for a while. It wasn’t long before curiosity got the better of me though and I found myself in the back of the van having a closer look at what I had bought. There were a  few surprises both good and bad as you often get with buying a project like this. I hadn’t noticed the large patch of rust on the fork stanchion, it was hiding behind the mudguard. Rather than replacing the seals I am looking at a new stanchion or maybe a good used fork as a replacement. Tit – I should have noticed that, oh well, it’s no big deal in the grand scheme of things.

On the plus side I decided to try turning the engine over. Before I did anything I whipped out the plug and bunged some oil down the bore. I gave it half an hour before gingerly trying to turn the engine by hand to see what would happen. Amazingly it turned over just fine. I turned it about 20 times and there was no sign of binding, coarseness or anything untoward – this is looking good.

Of course me being me I just had to know if it would turn over on the starter. The ignition was hotwired – which is rather too easy on one of these – a battery connected and the neutral and side stand lights obliged, did their duty and lit up brightly. I prodded the starter and it turned over enthusiastically like a child desperate to please it’s father in the vein hope of getting a biscuit or some other trinket. I wondered if I would get a spark – hell yeah, as our American brethren would proclaim – the spark was blue and healthy. It was getting serious now and I wondered if I was jammy enough to have compression. A finger was placed over the plug hole and when I pressed the starter this time the compressed air blew my finger away from the hole – this felt like it was really healthy.

You know what’s coming next, I just had to put some fuel in there and see what would happen. I knew the inlet rubber was knackered, that the carb wasn’t fixed on properly and that the spark plug was only finger tight. The little Rotax 122 single cylinder engine didn’t give a toss about any of that it sparked up with a cough and a splutter. A couple more tries and it burst in to life and settled down to a steady idle – I simply could not believe it. I have since found she last ran in 2009 – some ten or 11 years ago.

I can’t believe how lucky I have been aside from changing the inlet rubber and gasket I don’t think the engine actually needs anything. It will most likely get new piston and rings as I don’t know how old the ones in there are but I don’t think for one second that it needs a full rebuild.

Rather than just taking photos I did a couple of 1 minute long videos to show what happened – these are exactly how things occurred.

The first video can be viewed here:

And the second one here:

For the first time in a long time I get the feeling that God actually loves motorcycle breakers and every now and again shows his admiration by giving us a little gift such as this. My wallet loves this sort of thing.

I have started it a couple of times now and the engine is really sweet, I haven’t checked the gearbox or clutch out yet but these bikes are known to be fairly bullet proof in those departments and besides I don’t want to risk my euphoria just yet, there’s plenty of time for reality to strike on this one.

Aprilia RS125 rear discWith the workshop reorganised it was time to get the bike off the van and in to the daylight – the first job was to give it a good jet wash. Jet washing something like this always makes some bits look better and other bits look worse. The under seat area looked like a badly kept garden before I started there was moss, leaves, dead spiders and all sorts in there so that looked a lot better after a few gallons of high pressure water did it’s business.

Aprilia RS125 front caliperThe wheels and calipers were a totally different bucket of monkies – half the paint came off and they look rather sorry for themselves now. A fair bit of work is needed to sort that little lot out. It’s just time though, none of it will cost a lot, I will prep and paint it all myself – I was considering blasting and powder coat but I’m too stingey for all that. I will use decent etch primer which is the secret to a long life for paint on aluminium. I think I might need to change the rear brake disc while I am at it – have a look and tell me what you think 🙂 ?

That’s it for this time, next time I shall be taking bits off and getting lots of bits cleaned and painted ready to go back on. Still lots of decisions to be made and a whole ton of work to do but I am rather looking forward to it.

Article provided by David Powell of Boston Bike Bits.

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