In a bit to get some cheap track riding fitted in to my schedule, I picked up this recently.
I'll be getting replacement plastic to fit instead of the bust stuff that was on it before, and going through it from front to back replacing any crap fasteners and dodgy maintenance that it had in a former life.
I've already enrolled in a race series for this year, just need to pull my finger out and get my van sorted ready for the start of race season...
Starting by modifying the handguards so that they fit properly by drilling an extra mounting hole. I'll then shorten them to suit, and the other one needs a mounting block making as it'd been bodged with a dodgy fastener. I'll make a new one from a chunk of ally.
Most of the Kart tracks that allow bikes, and the race series in which I'm hoping to have a play, demand that sliders are fitted to footpegs to prevent track damage, so I fitted some, although they meant having to cut some material out from the pegs and grinding down a couple of the teeth too. Ten minute job, and another thing out of the way.
I got hold of a Mikuni carb too, apparently a popular upgrade from the standard Chinese carb fitted to the YX140 engine, but it needs a bigger main jet, and I need to check the pilot too - from what I've heard they like a fat main jet, and a small pilot to run a little on the lean side at low rpm...
For the Mikuni carb I had to get a different inlet manifold, as the Mickey Rooney hasn't got a flange (snigger) like the standard carb.
I bgot one easy enough, but the end doesn't quite match up with the size of the carb stub. Now, I could just leave it as is, or get a new end machined to match the carb stub and weld it to the inlet manifold... dunno, depends on time to be honest, and I'll probably fir the carb as it is now.
But I did go to the effort of cleaning up the inside of the manifold, which was horrible with loads of casting 'flash' and a scabby finish. It looks rough in this pic, but it's far far better than it was to start with...
Proper motorcycle work was avoided by making a stand, and then I'll be able to whip the wheels off and replace the crap wheel bearings with decent quality replacements. The stand was cobbled together with the steel from a couple of 'rescued' road signs, a piece of scaffolding plank and some goddawful welding...
Continuing to replace the monkey metal fasteners with decent quality stainless, alloy and the occasional titanium, and lockwiring the sump plug and filler cap in the process.
With the little bugger on the newly made stand, i got chance to spin the wheels and check the bearings. Crap. But I knew that. What came as something of a surprise was that the rear wheel span quite freely if span backwards, but didn't spin when given a shove in the normal direction. It was time for tea before I could investigate fully, but I think that there's an issue with the rear caliper...
Quad rear axel bearings... Can be had online for a fiver per side, 15 on the high side. Ordered to a local tractor parts shop, didn't check assuming around the same ballpark. Wasn't. 63€. Each. FKS but still FFS.
When investigating the issue with the rear wheel not rotating properly (spinning freely backwards, but not forwards) I clocked that the brake pads are somewhat larger than the swept area on the disc... I'll take the grinder to the (new) pads so that the only contact patch is on the braking surface of the disc itself, and not the 'spokes'...
All bolted back together, sort of, it was clear that the rear wheel spindle is 10mm too short, and was pulling the arms of the swinging arm together when tightened up. And, consequently, the wheel spacers were wrong too.
So, a swift bit of jiggling and juggling with two hands, a spindle, a wheel, some spacers, a rule and a digital caliper, and measurements were taken and another spindle and some spacers blagged off t'interweb. One bonus is that the new spacers will be aluminium and not steel, so a teeny tiny weight saving there.
Also, the weird issue with the rear wheel rotation seems to have gone away with the new pads (or new bearings?)...
Oh, and the velocity stack that I bought off a pit bike specialist that was designed to fit the 26mm Mikuni carb doesn't. Fit that is.
So, new spindle arrived, and with it and the wheel in place - and a piece of string drafted in for alignment purposes - it became blatantly clear that there would be fettling required to get wheel alignment...
More drastically, it also seems that the caliper plate torque lug thing (what is the proper name for that?) wasn't big enough to slot into the caliper mounting plate with the wheel centrally mounted. You may be able to see that in this pic...
So I was going to have to either extend the stub on the swinging arm, or the slot on the mounting plate. As my TIG is playing up (and my alloy welding is truly abysmal) and my MIG is working (and my mig welding is marginally less abysmal), I decided to extend the caliper plate to suit...
Two pieces of angle iron were cut and welded onto the plate...
Oh, and I decide it was high time I fitted the Mikuni carb, and when I went to take off the original carb I discovered an element of self-disassembly...
Back end all back together with modified caliper hanger and spacers made.
Just need to check it all with the spare sets of wheels that have slicks and wet tyres fitted...
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