Seb Hipperson's TRX850
By Ross Sharp - 17 Feb 17
Don't you just hate it when people beat you to something. I've always hankered after Yamaha's shameless Ducati inspired TRX850 and fancied sticking a fairing on one and tidying up the tail. That dream is a distant memory but there's usually a TRX in my eBay watch list at all times. Seb Hipperson must procrastinate less than me as he's been there and done it, turning up to Bike Shed London 2015 with this purposeful looking machine. That said, it's taken him two years to send us the photos. He does have the excuse of a shed full of other projects and a normal day job so we'll let him off. "The bike was for myself and in my head the brief was for it to be a half faired endurance race styled bike with a trellis frame, not too pricey with enough potential to mix it up on the odd track day. The Yamaha TRX850 fitted the bill nicely and I liked that it is slightly more unusual in comparison to the Ducati Supersport range." Great minds Seb... The TRX donor remained stock for about four months while Seb fathomed a plan. It took a further four years to arrive at this point, changing major parts of the build two or three times to achieve something that he was happy with. It can't have needed much as we enjoyed poking around at the Bike Shed show but as we all know the lure of tinkering and fine tuning is strong. Seb's a furniture and fittings fabricator by trade so spare time and finances weren't always in line with aspirations for the build. He started with a beaten up Imola style fairing from the 70s and set to work adding body filler to blank the central headlight, re-cutting a smaller asymmetric aperture and a pair of small vents. The whole thing was then reverse moulded to form the new fibreglass bodywork. A similar method was used at the rear, a small panel in the tail houses the battery and LED taillight. Hand bent tubes were welded in place under the new rear end to make a tidier subframe, the exoskeleton left on show to compliment of Yamaha's elegant trellis work. A slim tray sits beneath the seat with all of the relays, fuses and electrical gubbins inside.
Seb bent ally sheet and shaped foam to make a base for east London upholstery maestro Stan Leather to cover with a lovely aged hide, looks comfy too.
Anyone familiar with the TRX will be aware of the weak front end, there are a host of upgrade options so Seb pressed the stem out of his yokes and into a lower from a YZF750. The forks followed, complimented by R1 brake callipers and master cylinder. A braced swingarm from the same donor slotted in along with a wider back wheel (allowing a 180 section tyre) and a shock from a Kawasaki ZX10R.
The 270 degree parallel twin sounds great in standard tune but Seb wanted a bit more reliable grunt for track work so pulled the engine apart, re-honed the bores, installed new rings, lapped the valves and replaced the original CV Mikuni carbs with Keihin FCR41 flat slides. Stainless headers have been cut-n-shut to ensure the reverse megas bellow their offbeat soundtrack at an angle matching the subframe.
The engine, wheels and swingarm have been coated in satin black while the frame and bodywork were sent to a local car bodyshop for a few coats of Toyota silver. Seb cut the vinyl accents himself and had the whole lot laquered over. Seb was down at the 'Shed in Shoreditch a couple of weeks ago and not only does his TRX look menacing but it sounds tremendous. Great to see someone sticking at a project until they're happy with it, and then using it properly for knocking around London and dragging pegs at Brands.
Let's see what Seb unleashes from his shed in a few weeks time, the progress shots so far look promising.
Photos by Sam Napper