Aprilia RS125

Modification Diary

When I got the bike it needed a little bit doing to it. Firstly a new power valve spade as this was broken, a new chain and sprockets, some new pads and a damn good polish! Stupid me didn't get any photos of it this stage.

A week of riding it soon gave rise to another problem, corrosion on the unprotected USD fork legs. This promptly raped the seals and slide bearings. To my great fortune an immaculate pair off a 2001 bike turned up for sale on eBay with rubbish photos which I won for 12 on the off chance they might be good. They were MINT although needed new seals. An hour later they were spot on and ready to exchange with the dribbling ones on the front of the bike. Also another bargain on eBay showed up and thus an Arrow exhaust was fitted at the same time. I dropped the stanchions in the yokes at the same time although I think I could drop them even lower? this helps with the turn in when cornering or so I hear. When removing the mudguard off the old forks all of the bolts snapped even though I soaked them with Plus gas ( a great penetrating oil unlike WD40 which is NOT a penetrating oil) Before fitting new bolts the the replacement forks I ran an M6 tap through the mount holes and then fitted it all up with a splodge of copper grease to stop them seizing again. I found out how hard it is to work on the bike as well as it has no centre stand to keep the blasted thing upright.

As usual I either break something or get bored. I got a little bored with the looks of the thing and realised I had nothing custom to go to my bike shows on this year. So here is the beginnings of the new "speed" project. shouldn't take long, I have stripped it down, and mocked up a sort of street fighter thing in the process.

After stripping it down I cut the rear end off of the rear sub frame and welded in a few braces. More on this later but I want to get the running gear of the bike sorted first and smartened up a bit. Note some nice new parts have turned up in the post for her! Renthal final drive kit including a gold O-ring chain and an alloy rear sprocket. A 34 mm Dellorto carburettor, some carbon reed valves, a platinum sparkplug and a new air filter. The final pik shows the frame cross member freshly painted (spot the reliant pushrod holding it)

The swing arm was not in great condition and I have spent some time polishing it and removing casting flash. I should really have gone over the whole thing with wet and dry paper and started again but I don't have the time at the moment. Maybe a future job! I sand blasted the inner webbed sections though and then painted them black. Finally I got the rear wheel balanced which I forgot to do when I fitted the tyre. Also a new Avon AV 55 Storm ST tyre turned up at Ian's for me :) no idea if it will be any good but I've read good reviews on them!

Bored with the stock rotors I decided that I would need something a bit more ponsy for it. Some wavy ones were purchased for a cracking price along with new stainless bobbins and were fitted by grinding the old bobbins rivet off, punching it out using a reliant 850 pushrod, polishing the new stainless ones up and then fitting them along with wavy spring washers.

All this done and yet the disc bolts were rusty nasty things, more stainless here we come. A trip to screw-fix later and a few stainless steel bolts to be turned, and polished as well. Right on.

New bearings had to be fitted to the yokes, This was easily done by removing the old ones using suitable drifts, a bit of paint was added whilst the yokes were off. The new bearings were fitted with big drifts, using a socket for the top bearing and a tube to fit the lower bearing onto the bottom yoke. After fitting it back together a small 'C' spanner enabled me to set the preload up. then the USD forks were slid back into the yokes although I refitted them 15mm higher which drops the front of the bike and allows a faster turn in, when cornering. Next the wheel went back in loaded up with its new disk and polished up.

Before fitting the new exhaust the front of the engine needed a decent clean up to remove oil and the grit from the road that had stuck to it. I removed the side covers for a lick of paint, whilst the clutch cover was off I checked the clutch which was surprisingly good considering the amount of 10 000 rpm starts I have done!

With engine covers drying I cracked on making the rear sub frame and fairing. The sub frame was made from thin wall box section from B&Q, along with aluminium sheet drill screwed to the it. Not only does this keep the electrics safe but provides a convenient mounting point. At the same time I refitted the radiator and hoses. NOTE: you can refit those bastard little clips using pliers and a small Allen key instead of replacing them with unsightly jubilee clips. I used card templates to mock the rear fairing before I started to cut anything out of aluminium.

With no fairing on the rear I thought it best to squeeze the electrics and wiring in. The CDI, RAVE control for the power-valve, regulator/rectifier and indicator relay were all mounted. I also wired up the indicators whilst I was there. Then the aluminium cutting and shaping began. In the mean time I gave the fuel tank a coat of acid etch followed by a few good coats of high build primer. and some paint followed.

After the bike shows it was starting to piss me off without the fairings and I wasn't as keen on the look of it as I used to be. With some fresh paint I started to put it back together again. I also got a reasonable deal on an exhaust can on eBay from the current model RS which looks much better. I had to open it up to remove the studs which were turning though. When it was apart I rotated the back plate and it now fits exactly on the arrow expansion chamber perfectly.

With a MOT booked I had a deadline to work to, to get it back on the road. A little bit of finishing paint to make it look ok and some new front indicators it was back together. I made a quick temporary exhaust hanger out of two strips of aluminium as I couldn't find my 1.5mm ally sheet I had to make a nice one. Other than the battery being a little flat (even though it was plugged into the optimate) it fired right up and took me to the mot flawlessly and passed without even an advisory. Got it covered in crap due to the poor weather though! very pleased with the air blade screen, makes it much nicer to ride and get tucked in behind. Couldn't decide where to put the tax disc but found a nice spot out of the way, see if you can spot it in the last photo!

A few weeks later it blew up for some unknown reason as I always let it warm up, never ride it really hard for extended periods of time and always run it on top quality two stroke oil... rebuilt the engine.