Alex Winkler wears many hats. By day he’s an industrial mechanic—however by evening, he places these abilities to work in his residence storage, restoring and rebuilding classic bikes. When the weekend rolls round, Alex wheels his creations out of the storage and goes racing.
Whereas we will all respect a no-expense-spared showroom construct, there’s one thing particular about home-made customs which are constructed to be ridden. Alex lives and breathes this philosophy. Each of the bikes you see right here—a 1978 Yamaha SR500 and a 1980 Yamaha XS650—additionally occur to be his private flat observe racers.
Primarily based in Stuttgart, Germany, Alex has been constructing his personal bikes for the final 10 years as Twinshock Bikes. The SR500 was truly one of many first bikes he ever put a wrench to. He initially picked the bike up for round $900 on eBay, with a view to constructing a café racer out of it.
It was in tough form and barely working, so Alex began by rebuilding the engine, bumping the displacement as much as 620 cc within the course of.
He tackled the cylinder head work himself as nicely, which included porting, sharpening, and machining to accommodate bigger valves. Megacycle efficiency cams have been put in for good measure.
Alex additionally added a full hand-made exhaust system, from the manifold to the silencer. A recent Mikuni TM40 flatslide pumper carb was added, and the inventory airbox was swapped for a much less restrictive pod filter, to maintain issues working easily.
By the point the engine went again collectively, the little café racer was working like a champ and placing down a wholesome 49 hp… nevertheless it didn’t keep a café for lengthy. A number of years later, Alex took an curiosity in flat observe racing, and as soon as once more the little Yamaha went onto the chopping block.
The entrance finish was upgraded with a set of Yamaha XT550 yokes, whereas adjustable Koni 7610 shocks went on the rear. Alex stored the usual 19” SR500 entrance wheel, however laced a 3.00×19” KTM rim to the rear hub. That meant he might match correct Mitas H18 flat observe tires at each ends.
A fiberglass gas tank and flat observe tail piece sit up prime. Alex completed the construct off with {custom} sprocket and brake guards, machined rear units, and a home-made fork stabilizer to shore up the dealing with for race use.
As Alex continued to construct and tinker through the years, his assortment of spare elements took on a life on their very own. Sooner or later he realized he had every little thing he wanted to construct a second Yamaha observe bike—so naturally he did simply that.
Legally the white bike you see above is a Yamaha XS650, nevertheless it’s about as a lot XS as your typical pound pet is a Labrador Retriever. We’ve received no complaints with this mutt’s pedigree although, as a result of Alex labored some severe magic with that elements bin of his.
Technically, you’re nonetheless taking a look at an XS650 engine sitting in an XS650 body. Alex bored the cylinders out to 840 cc, and put in a pair of Wahl Spezialkolben pistons (that’s German for ‘particular piston’), with a set of Nissan Bluebird (sure, the automotive) cylinder pins. There’s a efficiency ignition from Boyer Brandsden too.
The carbs are Mikuni TM36 flatslides, the filters are from Ok&N, and the exhaust system is totally {custom}. Based on Alex, the engine now makes a strong 68 horses—which ain’t too shabby, contemplating the bike has been stripped down to only 340 kilos.
The inventory entrance wheel was changed with a spare 19” SR500 hoop that Alex had useful, which now sits between a set of first-gen Yamaha FZR1000 forks that additionally occurred to be laying round. All the rear finish was put collectively from spare elements too, and features a swingarm from a Yamaha SRX600, a rear wheel from a Suzuki RMZ, and one other set of Koni 7610 shocks.
The bodywork features a custom-painted fuel tank pulled from a Suzuki GT50, and a stubby rear fender. The XS additionally sports activities the primary seat that Alex has stitched collectively himself. It’s a good-looking two-piece leather-based affair, and is perched atop a {custom} subframe.
Alex had a pleasant Brembo brake setup from a KTM 690 Duke stashed away, so he machined a {custom} bracket and put it to work on the rear. It was the identical story (albeit a way more troublesome set up) for the Yamaha’s new hydraulic clutch system, which was pulled from an unidentified Ducati in some unspecified time in the future over the past decade.
There’s no scarcity of hand-machined elements scattered by this construct. All of them carry the identical unmistakably utilitarian design that Twinshock Bikes’ builds share—like a plethora of ‘pace holes’ so as to add lightness.
Remarkably, there’s not an inch of CNC-machining on both of those bikes. Alex refuses to make use of digitally-aided strategies, preferring to manufacture every little thing by hand to maintain his builds as “old fashioned” as doable.
These two classic Yamahas make a good-looking pair, however we’d wager that they appear even higher in movement. The truth that they get raced rattling close to each weekend, and nonetheless clear up this nicely, will get main props from us.
Twinshock Bikes Instagram | Photographs by (and with due to) Kati Dalek
