Monday 25 May 2009

Screen power: enhanced



Armed with 2 sheets of 3mm 50cm x 50cm perspex (one clear, plus one in a very light blue tint, shown in the picture), plus a few hours sans kiddies, I had a go at bodging up a replacement for the PUIG screen. I should note that the PUIG did hold together fine, and in fact isn't a bad screen for the price, it's just that I wanted something a little bigger, and I'd cracked the PUIG when fitting the 8" screen to the 7" light on the Huonaio. With hindsight, I could definitely have avoided that by heating the screen before fitting.

The screen fabrication was pleasantly straightforward. A 7" plate provided a handy template for a semicircular hole in the bottom edge. A narrow fine toothed jigsaw blade easily followed the inside of the curve. Then I angled the sides into a basic inverted pyramidal shape, added a gentle curve to the top edge, and nibbled a little off the rear lower corners in order not to foul the indicator stalks.

Then it was out with the paintstripper heat gun, and the shaping was begun. It's a fairly simple process, it just requires patience and re-adjustments to get the lower sides curved in to fit the sides of the headlight, and a gentle curve across the whole screen. Clamping the bottom edges where the screen will attach to the headlight between (e.g.) two pieces of wood helps to keep them flat, or else it's easy to end up with very warped lower edges. If you're doing this yourself for the first time, then just take your time, move the gun steadily back and forth across the piece where you want the bend so that it doesn't get scorched, and don't force the perspex; once it gets up to temperature, it suddenly becomes very pliable.

Late in the process, I noticed that I'd stuffed up the top edge a bit, and I had to go back in with the jigsaw to even it up. Since the screen was curved by this point, I couldn't lay it properly flat, and managed to add a small crack. Ah, I can live with it.

The screen is attached just by bolting it to the headlight mounts, with 8mm holes drilled as far from the edges as I could manage. Just go up the bits one mm at a time and go very gently, and the perspex shouldn't crack. When I was doing the bolts up, I noticed that the twisted bottoms of the screen still weren't quite square, so I heated them up again gently while doing up the bolts. One side did crack very slightly, but I'm hoping that it holds together. If not, I can do the whole screen over, and this time I can just use the first attempt as a template to shape a second screen. Score!

It's a relatively tall screen, but it's resting against the instrument binnacle (and could be secured to it with a spare number plate sticky-pad that I'm sure I have somewhere), so I'm fairly happy that it's supported well enough. Actually, even at 50cm tall, it still manages to direct the airflow right onto my face... gaaaah. I'm not sure I want to go taller, but now I'm thinking... hmmm... could I lower the seat a bit?

Well, idle hands make for the devil's work, don't they?

Tuesday 12 May 2009

Size matters



Well, numbers matter.

The aforementioned 4+2 converter plug from Xian came with 5 wires (i.e. one missing). It fitted the sockets on the bike and CDI just fine, but the bike wouldn't start. A continuity check revealed that all wires were secure. Hmmm.

A visit to the Chinese Bike Forum over the weekend revealed a previous purchaser who'd also had a problem, which he'd solved by getting another converter with all 6 plugs wired up. A quick phone call to Xian got a 6-wire converter winging its way to me, entirely at their cost - they didn't even want the 5-wire one back. Very decent of them. They also said that they come with 5 wires from the Chinese supplier, and work on 90% of bikes. I've since found that older HN125 models do only have 5 wires on the bike side of the ignition; mine has 6 though, and needs all 6 wires.

Oh, I blew the ending: the new plug works fine with the POSH CDI. A quick lunchtime jaunt revealed a modest improvement in eagerness at mid to high revs. That's not the way I like to ride, but if you want or need to work your bike hard, the POSH seems like a good buy.

Since I'm unable to resist the urge to keep fiddling, I've got an NGK DPR9EIX-9 spark plug on order. To translate, that's 12mm / projected insulator / resistor / heat rating 9 (runs cooler than normal) / 19mm reach / iridium / 0.9mm gap. It's perhaps not ideal for the bike: I'll really have to try it out. This excellent CG 125 guide suggests trying it since as well as giving a stronger spark, it should help prevent power fade during extended high speed running. This isn't an issue for me normally, but I'm considering trying a jaunt up to Inverness in July with a fellow Huoniao (HN125-4F) owner, and am gradually trying to get my bike up to scratch, since his bike seems pretty pimped.

Since I can't find a cheap screen that I like, I've bought a couple of 3mm 50cm x 50cm sheets of perspex, which I'll have a go at cutting and bending with the aid of a heat gun to see if I can get a usable screen out of them. If I'd thought about it, I'd have heated the PUIG screen before fitting it to the smaller HN125 headlight, which might have stopped it starring.

Ah well - if it hadn't starred, then I wouldn't have the opportunity to get my hands dirty (and burned). That's what this bike is all about, after all.

Friday 8 May 2009

Performance anxiety

To my mild chagrin, there's very little space left to actually bolt things on to the bike, and it still hasn't suffered a failure. So out of desperation, I've had to resort to performance tweaks.

First, I fitted a 17 tooth front sprocket in place of the 16 tooth that was already replacing the stock 15 tooth. Interestingly, the rear sprocket is already a relatively small 43 tooth, giving the bike a long gearing, longer than that recommended by Xian Racing. Still, it felt good with this ratio, keeping the revs nice and low at commuter speeds, and I can always drop down a gear if the bike struggles. Theoretically, it will make low speed manoeuvres a little trickier, but I haven't noticed any difference so far.

I only barely managed to fit the 17 tooth sprocket with the stock chain. You (well, I) wouldn't think that such a small difference in the sprocket would tighten the chain up by so much, but it does. Even with the axle fully forwards, I couldn't get the front sprocket on with the chain on it, or the chain over it while it was fitted. I had to take the chain off the back sprocket, fit the front sprocket and chain, engage the chain on to the top rear sprocket then turn the rear wheel to wrap it fully round. It was touch and go, but once it was all on, there seems to be enough slack in the chain. Weird.

Next up, an after-market coil and HT lead.



I'm buying the marketing here: I have no objective grounds for believing that this unit is superior to the stock coil and lead. However, there are two things to bear in mind:


  1. It's very unlikely to be worse.
  2. It's red and orange, so it must be inherently faster...


Subjectively, the bike did feel smoother on my commute this morning, although (especially with the 17 tooth sprocket) I wasn't reaching the revs where a stronger spark should make a difference.

I should give the coil a good exercise on its own, but this afternoon, a new CDI ("POSH" branded, as recommended by a few Chinese Bike Forum posters) turned up, and I couldn't resist plugging it in.



Purty! It comes with a 4+2 rounded GY6 plug socket, so I've also bought a converter to the square 4+2 STD plug on the HN125-8. It's much bigger than the standard CDI, so has to nestle down the side of the under-seat area. At the top right here (where the old CDI was) you can see the accursed side-stand switch. I'm retaining it just in case it gets added to the MOT regs. I was watching Long Way Down, and was amused to see Ewan McGregor's BMW pimpmobile immobilise itself due to a defective side stand switch. On the advice of BMW UK, he just chopped it off and twisted all the wires together. Proper job!

Wait, did I say "Huonaio"? I meant "Reliant", of course.



Leave me alone - I'm in my Happy Place.

Saturday 2 May 2009

That's pretty pimp, right there



I think we're just about there as far as outer-wear goes.

That's the bike with a Pioneer Nevada front mudguard on - cheers to Llexeter for a next-day delivery when they finally sourced it - and rear crash bars.

That's two gambles that paid off. The mudguard is sized for the slightly smaller and not quite-so slightly wider 110/90 16 tyre that's fitted to the 125 Harley clones. In the event, it fits just fine over the Huonaio 3.25 18 wheel, but not quite so fine between the forks. I had to wiggle it in this way and that way to get it in place, and it's compressed just a little. It also needs to sit above the mounts on the HN125. I briefly considered cutting up the stock mudguard that I'd removed, but was struck with a rare attack of common sense: what if I couldn't get the Nevada guard fitted? Instead, I just fabbed up some brackets from... well.. I considered chopping up one of the missus' baking trays, but I have to admit that the mounts currently holding the guard on are made of a re-purposed tin of Quality Street covered in black Japlac. As an aside, this is an amazing paint; even when put on with a stiff scraggly brush, it spreads out into a lovely even coat. I'm slightly tempted to see if it can give a smooth coat on the tank and panels without resorting to 25 coats of wafffer thin spray paint. Slightly tempted.

The rear crash bars are 20 year old "new on the shelf" Britax branded bars labelled as being for a Honda CM200 T, in nice condition for their age. The brackets on the end of the bars rotate, which would allow them to fit a variety of bikes, and they went on the Huonaio no problem at all, attaching to the top suspension mounts, and the pillion footrests. They'd get in the way of a pillion rider's foot, but since The Man won't let me carry a pillion anyway, that's not a problem. They also make putting the bike on the centre stand a little more difficult, and can catch a trailing leg when pulling away, but I can live with that for the added protection from a drop or side impact. Plus... more chrome. Mmmm, chrome.

As the final touch, I fleaBayed some decal injket paper and printed up some labelling to cover up the Huoniao logos on the tank and side panels, to confound interested onlookers. I swithered over a DOOP logo, or War Rocket Ajax, but in the end I had to revert to type. The tank now sports an "Ad Astra per Aspera" Starfleet logo from one of those fictional Star Trek series, and the side panels boats a portentous name... the Reliant. Nobody - nobody - tell my daughter why she's called Miranda.

With the bike set up just so (the chain needed half a turn of tightening), I went for a jaunt today just for larks. About 40km - whatever that is in real money - across some gently windy A roads (the old, safe bit of the A77) and then back over the B764 Eaglesham moors road. Interesting road; it's a full width road which since it was bypassed is now marked out as "single track with passing places", with wide "cycle" tracks on either side. In practice this just means that road traffic going both ways does a little 60mph shimmy as it meets. Since our little Chinese bikes can easily sneak down a cycle lane, it's a fun ride. Later, I indulged in an outing on the local dual carriageways.

On this run, the bike's strengths and limitations become clear. It's a joy to ride, stable and composed at anything up to 50mph. Note the up to. When trying to achieve more than that, the vvviiibbbrrraaatttiiiooonnnsss start to come in. Nothing overly unpleasant while riding, but my feet were tingling when I got off! Any kind of uphill gradient, even a gentle one, quickly eats into the top speed, putting it more in the indicated 40-50mph bracket. On the straight, an indicated 60mph is easy enough, and downhill with a tailwind sees close to an indicated 70mph. The "tailwind" thing isn't trite; on little bikes like this, the wind is a significant factor.

Something that becomes apparent is that while the maximum power is at 8500 rpm, you only get that power if you get to that rev range. Easy to say, but the understanding only comes with experience. If the road conditions - incline, headwind - produce more drag than the power produced at (e.g.) 6000 rpm, then the bike won't get to 6001 rpm. The bike has more to give, it just can't give it.

That's perhaps more negative than it sounds. I was pleasantly surprised by how well the bike performed on the local dual carriageway. I was actually able to overtake cars past an indicated 50mph. Cautiously, carefully, I hasten to add, but the bike can do it when needs be: it's a 125, but it's a geared 125, not a scooter.

It was a lovely day, and the biking brotherhood was out in force. Many nods were exchanged - I do love a good biker nod - and on a supermarket stop off, I parked up next to a lovely red Jinlun JL-11. I'd be the first to say that Jinnys, Nevadas and the other Chinese Harleys (Charleys?) are absolutely gorgeous bikes with really consistent accessorising, but I don't feel that plonking the Huonaio next to the Jinny let the side down. I now have a custom "Custom" bike that is genuinely unique.

And I'm absolutely loving it.