Aprilia RS 125/ KTM 640 LC4 Supermono

The last pic of the front end is pretty much as is now, only difference is it all fits and the wheel goes round. Disc found to be 2.9mm so way below min wear, have ordered a better one, New wheel bearings were being fitted last night till I hit my thumb instead of the drift. Ouch! I'll finish that off when the bleeding stops. Had to take a bit off the caliper mounting lugs, also off the lugs on the forks. Spacers for the disc 3mm out from wheel and a couple of mm off back of caliper body. So now Caliper clears wheel spokes, Caliper is central over disc and wheel is central between forks. Made Axle out of RS/GSXR and machined new alloy collar for non disc side. New tyre fitted on a nice sunny day in the garden last weekend. Just a few new fasteners to come this week and I can bolt it up for the final time. Brake line from RS was too short so one coming soon 625mm long and that's about it, hopefully. This conversion is just about do-able but its not easy. If you are shy about

Been busy doing some engineering this week. Fitting the forks is a breeze as they fit in the rs triple clamps, however the rest is not so easy. There is an option on the forks of 4 pot or 6 pot calliper, well it would be rude not to i thought. not sure if the 4 pot would have been simpler but its not been easy. The GSXR wheel almost certainly wouldn't fit as the RS tyre doesn't have more than about 5mm clearance each side. The calliper fitted with the wheel centralised clangs on the wheel webs.  I took the calliper apart and removed a piston on the back half and measured the casting thickness at 6mm so i machined 2mm off the back of that, took a few mm off the back of the calliper mounts and likewise on the fork mounts, its nearly there, i'll get some small spacers maybe 4mm to space off the disc and we should be about there. The axle is another story. GSXR axle is 25mm RS is 20mm. You can't get bearings with 25mm id to fit in the RS wheel so it needs a s

Been busy again today rebuilt the forks. Watched you tube video from Del boys garage for doing the seals on USD forks, however when i got into it these are different design and need a puller to compress the spring in order to get at the lock nut. Made a gizmo to grip the top sleeve and used straps to compress the spring. All done but took most of the day, new seals and 7,5 weight oil.

Needed to take front wheel out and had a bit of a job. Every single fastener had either seized or broken, had to drill most bolts out. Gave up with calliper bolts as severely rounded off. Thats the trouble with RS125's every young lad has worked on them with a mulgrip tool selection. I wanted a decent front end an tis isn't it. Felt like one leg hasn't even got a spring in it. Did a fair bit of research to see what would fit. Decided the best value were GRXR, lots of them are virtually identical so will fit the triple clamps. These are GSXR 750 SRAD and were advertised on eBay as "Horrible condition, worst on Ebay" Decided to have a punt at £29.99 inc post, and they came today. They are all there and straight, nothing broken or cracked, few broken bolts but nothing i can't fix. Need new seals and dust seals, they came today too. I cleaned one of the lowers up and it looks good, the sliders are good too.

Been working on cooling system now exhaust is done. Bought TDM850 Rad which has a pressure cap thinking i wouldn't need a separate expansion tank. Now the rad is mounted as high as i can get it, the filler is not the highest point on the system so will need a small expansion tank to fill from. Ordered a RS125 one that should do the job. Fitted some hoses but need some more bends to plumb the red in neatly. Its very congested and tricky round the water pump area.

Just finished the exhaust, I used the 2-1 section from BMW F800S plus the rear section, a bit of old Ducati 749 pipe for the link pipe and the rest i fabricated from 38mm stainless Mandrel bends. I got 105 deg for the top bends and 55 deg for the bottom bends. I had to cut close to the bend for the top to get the downpipes close to the engine. In doing this i found the pipe wouldn't slip over the exhaust stubs. The diameter of the tube is reduced in the bend and a couple of inches either side. I had to weld a short section of straight pipe at the manifold end, bit fiddly getting correct angle. All fits ok, have strengthened can hanger now and will make a support underneath next. I managed to weld using a stick welder, i now have a small inverter that goes down to about 20 amps. Made these welds at 30-35 amps using 1.6mm stainless rods.

Finally after 2 weeks of waiting the bottom bends have arrived. Just spent a couple of hours fitting the first, ill do the other one tomorrow and then thats the exhaust about sorted. Ill make a slightly longer link pipe to move the can a bit further back. The other thing that arrived today is a pair of Metz M7 RR tyres from trackday tyres, they look almost new so for £100 were a bargain. Date codes show late 2014 which is ok by me.