Aprilia RS125 rear seat hump

Two Stroke on a budget – Aprilia RS125 (Part 4)

Two strokes on the cheap – part 4 Coronavirus special.

We live in very strange times. I don’t know when you will be reading this but I am writing it in the very middle of the country being shut down in an attempt to get through this global pandemic. Everywhere is shut or running reduced services, I am diabetic and so classed as high risk so nipping to Halfords or anywhere else isn’t really an option. So my activities will be limited to what I can get on with which will also give me something to do while isolated from the outside world.
Aprilia RS125 tank hole
First job was to fit the rear seat that I had ordered from Ebay – I had a brain fade moment here. In trying to keep with the ethos of building on a budget I went through all the seats on ebay and tried to find the best one at the lowest price. I then rather stupidly ordered the one that had no strap on it rather than the one I had spotted at the same price that did have a strap on it. Bugger. Oh well it was only £15 with the postage so it’s not a massive issue. If it irritates me enough I will replace it but it will do for now. The performance or usability isn’t affected so I will most likely leave it, I will check to see if it is available as a separate part. Incidentally I intend to keep a bit of a running total from here so you can see exactly what it is costing me in bits. I’m good to you. A quick clean up of the arse end , a rummage through the bolt stash and that was put where it should be.

One of the jobs I thought I could get on with was to swap the lock barrels, turns out I couldn’t because the ones I had in stock turned out to be different so I will have to buy something in. I noticed while doing the tank that the rear mounting rubber was missing. As I had no chance of finding one at the moment I went in to “make” mode and had a rummage until I found some bits that would McGyver together to make something good enough.

Here’s a sequence of photos to show how that worked out.

The hole in the tank.

Aprilia RS125 tank mount


Aprilia RS125 home made tank rubber mountThe kit of parts – two grommets – the holes in which were still too big, a short length of fuel tube to make the holes in the grommets smaller, a nut and bolt from the stash – 2 washers will be added and the bolt will be shortened when I know it all fits.

It all fits 🙂 Cost = nothing.

Next job – another minor one was to clean up and repaint the rear footpegs and hangers. Nothing much to say really but as I had the paint in it was something I could do so do it I did. If you see what I mean, sadly I only have an after photo as I forgot to take one before I started on them. They had light rusting but no deep pits.

Aprilia RS125 pillion pegsThey look a lot better now, cost virtually nothing, just a bit of elbow grease and a few squirts of paint. Let’s call it a quid.

Aprilia RS125 aluminium frameWhile I was looking around the bike for other jobs I could do my eye kept getting drawn back to the aluminium frame and the astonishingly good welding that holds it all together. My mind was taken back to those days when I was 17 and polishing my KH250 triple to within an inch of it’s life on a sunny Sunday morning. I tried to ignore the fact that it’s pissing with rain and only about 8 degrees in the workshop. Now, I will stress that most of the ally is hidden on my bike so this may seem a wee bit futile but as I want to use this as an example of what can be done on a budget this seemed like a good exercise. You can get electric polishing devices for this but as they cost money I decided to do it by hand – the only materials being two pieces of rag and 10p worth of Solvol Autosol – the same product I have been using for over 40 years and still, in my opinion, the best. The results below took about 25 minutes to achieve with my arthritic old hands. I have done one side but not the other so you can get the idea of before and after:

I will give this another go to do a better job of it but it’s coffee break time now. Hopefully it gives the idea that not all restoration costs a fortune and that some bits can be done at very little money but can make a huge difference to the overall job. Only a few pence to add to the total so I’m not even going to count it. I will do the rest of it and the footpeg hangers and swingarm. It’s quite a lot of work to do it all but I think it will look really good for virtually no financial outlay. If your ally is fairly deeply pitted or just a bit too far for polish try using some really fine wire wool to apply the polish. They sell it in all sorts of grades, the finest is 0000, it’s brilliant for this sort of work and can save a fair bit of time. You can also use wet and dry if the pitting is really bad, I like to use it wet and to start with something about 800 grit and finish with 1500 before going over to the Autosol.

AutosolNow, here is another chance for you to learn from somebody else’s stupidity. Never, ever leave the tube of Solvol on the floor! I must have made the same mistake half a dozen times in my miserable life and every time the end result is the same: dog turd surfing only with solvol because you can’t get white dog shit any more.

Oh well, I was going to polish the swingarm anyway so might as well put it to use. Yes, I am so mean that I scraped it up and used it – waste not want not and all that. The swingarm will probably eventually come off so I can do a proper job but thought I would give it an initial once over – seemed sensible in the circumstances.

Aprilia RA125 swingarmStill looking for jobs I can do while the lockdown is in place so I took a few bits off to get at and clean. First was the radiator – it was in good enough nick to reuse, just needs a repaint – etch primer first as it’s ally then matt black to replicate what it was originally. It’s another one of those 10 minute jobs that costs very little to do but adds a lot to the overall job.

While I was at it I decided the chain was never going to clean up to an acceptable point. I don’t think it has done many miles but it had pretty thick surface rust and some of the links were very tight. A new chain is fairly dear – the cheapest are about £28 and the dearest can be easily twice that. I like to use the x ring chains – they are like o rings but there is a lubrication groove in each of the rings which seem to hold lube much better. I had a spare new old stock chain in my workshop – not an x ring but as this is a budget build that’s what I am going to use. This is a decent enough chain – stay away from the really cheap Chinese ones, a snapping chain at speed can do an alarming amount of damage to both bike and rider. The crafty buggers have become very good at making poor quality stuff look almost exactly like the better stuff but they often use much cheaper material with lower tensile strength – be warned. Buy from reputable places like www.wemoto.co.uk and you know you are getting something that will last and not put life and limb in danger. Lecture over.

Aprilia RS125 exhaustWhile I had the exhaust off I thought I would give it a really good clean with the wire brush in my grinder – oops. There are now several small holes in it and some pretty serious flaking of the metal up near the manifold – ie the hottest part that also gets rainwater off the front wheel – a devastating combination. No real choice here, a replacement will have to be found. Scottie thinks he has one stashed away, I hope he does as £180-280 for a new one isn’t exactly doing things on a budget.

Aprilia RS125 corroded power valveAs the front of the engine was clear with the exhaust and rad off I had easy access to the power valve – these things tend to seize up as they are in the exhaust port so now seemed like the obvious time to check it out. Sure enough the blade was stuck. Didn’t take much to get it out but it definitely would not have been working like that. There was a fair bit of carbon build up on it, a couple of squirts with a decent carb cleaner soon had it spick and span and sliding in and out nicely. There is an o ring seal in the body – it’s always worth changing while it’s in bits and a new gasket is a good idea while you are at it. When reassembling make sure the bevelled edge is pointing down and put the body back so the slot faces up. This was you can see from the top whether the valve is working or not – it’s just much easier than trying to view it from the bottom. Also pay attention to where the cable goes in to the valve slide – they tend to wear and the cable can then pull through. A new blade is over seventy quid so I am glad mine was ok. I think they are put under serious strain if the blade seizes in the slot as the solenoids are pretty powerful.


The other thing I too k a peak at while the exhaust was off was the piston, which can clearly be seen through the exhaust port. I am pretty certain it’s a brand new piston in there, which was a pleasant surprise. I’m going to run a compression test on it if it’s good I’m not going to replace it – no point going to a whole load of effort and cost for no benefit and besides the things I am going to need are adding up to a fair old chunk of change so no point driving up the cost on stuff that doesn’t need doing.

I have it out in the sunshine at the moment and it’s clear the frame and swing arm need a lot more polishing, I will get that done before moving on to the nest bits. Getting parts is going to be tricky but I may be able to get a few minor bits ticked off while I am waiting. So that’s it for now, hope you and your families are all safe, Next time I shall be doing some more polishing and looking at the brakes. Seeya, Dave.