Gluingg it all togetogether
The idea was there, and o were the parts to make it t happen. Now it’s time to o put all the bits together anda build a motorcycle... In last month’s issue, I took you through the start of Project RGV, going from the original idea scratched out on the back of an invoice for a 1994 Suzuki RGV250 to the point where we had some parts bolted together in the workshop.
With the tiny chassis now painted in a tidy gloss black and fitted with that achingly sweet Aprilia RS250 swingarm, 2004 Suzuki GSX-R1000 front end and the OZ race wheels from a 2004 Honda Fireblade – plus the quite frankly massive 320mm front Brembo discs, radially mounted calipers and svelte underslung rear caliper – the whole project had finally started to look like a motorcycle.
Mostly, that’s down to the skills of Nigel Kimber at NK Racing: a man who has the patience of a saint, especially when dealing with a magazine editor who has an idea that just won’t go away. A big thing I didn’t like about the original RGV250 (and this is my fifth one) was the skinny tyres and wheels; it just didn’t look right to me. At the time of its popularity, the RGV was sold as a mini-GP bike. It certainly looked good as long as you didn’t take too much notice of the 140 section rear tyre and 110 section front, but here on our project was something altogether more meaty.
Yes, I’ve already come in for criticism for fitting a pair of wheels to the 250 that will take a 190 section rear tyre and 120 front. There appear to be plenty of experts out there who can’t wait to tell me how I’ve ruined the handling on the bike and how I’ve robbed it of the very qualities that made the 250 such a fun bike to ride. They claim that the wheels won’t turn as easily, that the cornering abilities of a housefly that so dominated the reasons for getting a 250 on the road will be nullified by the bigger rubber. Will it though? Remember, this is nothing more than theory. I haven’t ridden the bike yet and haven’t been
able to find anyone else who’s tried anything quite like this so I can’t say anything for sure, and won’t be able to until the first test ride. But, armed with nothing more than a couple of ideas and pretty big spanners, I can’t quite see how the bike’s handling will slow down.
The new front end has the same rake and trail as the original; apart from a few millimetres here or there the wheelbase is still the same; and as for weight – the new wheels and brakes are considerably lighter than the original parts that went before, by a total of four kilograms all-in. The wheels are 17-inchers instead of the original 17 front and 18 rear, but apart from that there shouldn’t be much difference. And the real trick will have come in changing both wheels – fitting a matching pair that have been designed to work together and with the bigger brakes should ease any potential problems with handling.
Previously, there have been quite a few specials built with a larger rear wheel but the same front. When that happens, the added grip and mass of the wheel at the back tends to push the front wheel and that will – if you’ll pardon the expression – properly bugger up the handling. So, as set in my mind as the bigger wheels were, I did do some asking around to see what others thought. Through this job I’ve met some serious mechanical brains and armed with a theory and little else I collared a recently retired HRC test rider I’ve known for some years now, Mr Dave Hancock. In his working career, Dave (who helped develop the original FireBlade) earned his living by developing and testing the Hondas we got to see over a span of more than 25 years. If anyone would be able to give me a definitive idea of whether my idea would actually work it was him. “Yep, no problem,” Dave said when I explained the plan: “What you’ll find is that, with the changes you’re making, the bike will turn into corners easily as well as it did on the original heavy wheels and Bridgestone Cyrox tyres. The new parts you’re fitting to the bike might actually let it turn in a bit faster than stock given that the set-up is less heavy, too. But the benefit will come most of all when the bike is leant right over in turns. On its side it’ll be very stable because of the bigger tyre footprint. It should be good fun.”
Now, I’ll be honest with you. Up until he’d said that to me I was seriously starting to doubt whether this project would really work, but after getting the seal of approval from an HRC test rider, well, there was no stopping me. The idea was now ratified by a man who really knows about this sort of thing. If he said it’ll work, then it’ll work. And, here’s the rub; with the wheels, massive 320mm brakes, chunky radial calipers and suspension in the tiny chassis – and the small motor almost lost in the wrap-around frame – it just looks right. The bigger tyres and wheels fit the bill nicely and, with the beefy brakes gloriously on show, the RGV now looks much more like the 250GP machines that were axed by the loons at Dorna, the company that looks after the MotoGP championship.
Originally, I’d wanted to perhaps put a 500cc two-stroke motor in this bike, but once I was told that the 250s were to be phased out I was so outraged I decided there and then to keep this bike as a 250. It turns out around 64bhp on the dyno.
It’s plenty for the sort of roads the RGV was always a weapon on. This is my homage, then, to one of the truly great racing classes and I cast a pox on the person who made the decision to rob us of 250cc GP exotica. Besides, the 500 will have to go into the next project bike...
Back to this one, and with the wheels, brakes, suspension and swingarm changed it was time to focus on the other parts, the ancillaries, before adding the bike’s ‘look’. The motor had already been given its new top-end but essentials like mudguards and huggers, chain and two-stroke autolube bottle, smaller battery and footrests needed to go on. On top of that, the exhausts need fitting. I’m using Tyga pipes and end-cans for the project and they really are incredibly lightweight, tipping the scales at just 3.5kg for the pair instead of the original unit’s 11kg complete weight. That’s a huge saving right there.
I’ve also stuck with Tyga for the bodywork kit which is made from carbon fibre (so, again, it’s incredibly lightweight) for two reasons; it looked like a current GP motorcycle and was road legal. Although Tyga does bodykits built entirely for track work, the Thailand-based company’s road kits come with tiny light units front and rear to keep you on the right side of the law here in Blighty! The quality is high, but fitting such a svelte seat unit to the firm’s subframe is tricky. Incorporated in the tiny unit is the two-stroke bottle, battery housing and remote adjuster for the rear suspension unit. The whole unit itself is sealed with a close-fitting undertray to keep everything inside dry and away from the grime flung up by riding on the road.
When it came to the two-piece fairing there was patience needed to sort out the mounting brackets, side-stand access and lining the whole thing up. Because the Tyga set-up is so light and thin there was a very real worry during fitting that the whole thing could be bent, cracked or damaged in some serious way with little effort. As it turned out, the Tyga fairing and seat unit were surprisingly resilient while we fitted and pulled all the pieces around.
With the bodywork on, the bike looks a million quid, exactly what you’d expect from a modern 250cc two-stroke road machine, if one from a big manufacturer still existed. But we’re not finished yet. Getting the bike to this stage has been relatively easy, but it’s not that the final niggles and clean-up issues have surfaced.
We’ve got to make a bracket for the KOSO digital dash because it needs to be buried further into the back of the nose of the bike than the original chunky instruments. That’s no big deal in itself, but there’s a more substantial issue to sort at the back end of the bike where we’ve found that the gorgeous exhausts now just, just, miss the rear tyre. The bigger wheel and swingarm change have taken up those crucial millimetres which means we will have to cut the rear pipe and extend it ever so slightly.
Despite this, it really is ‘so far, so good’. The bike looks the business, has come together with much more ease than I ever thought possible. All we’ve got to do now is sort out the niggles before it gets out on track for its first test. Then we’ll see how well the theories work in practice.
24 How much lighter (in kg) the project is over a stock bike