Based on a 1982 BMW R45
This bike started life as a humble R45 (450cc), the smallest engined Boxer twin in BMW's range and produced as an entry level bike.
When Tim, our customer, acquired this bike it had already been converted to a 650, as the cylinders, heads and carbs are interchangeable and a common modification.
Well, Tim wanted more, lots more!
He wanted a Street Scrambler style, more power, high level underseat exhausts and paintwork to give a nod to its German heritage.
Fabrication of the exhaust was first and made in stainless steel then sent off for Ceramic coating which is a great insulator and negates the need to have unsightly wrapping to keep the heat away from certain areas.
The motor and transmission were then torn down for refurbishment and upgrades. A Siebenrock 860cc power kit was installed which contains high comp, lightweight, short skirt pistons and new lightweight Nikasil lined cylinders. The original carbs were junked in favour of a pair of bigger 34mm Mikuni's with high flow Ram Air filters.
The clutch was beefed up to cope with the extra power (approx 30% more) with a heavy duty plate and spring. The transmission was treated to all new bearings and seals along with a higher ratio 5th gear which keeps the revs down when cruising.
Once the frame and swingarm had been de-tabbed of all the unwanted brackets and the blasting and powder coating had been finished, all new bearings and seals were fitted along with the refreshed forks and brakes, new longer fully adjustable remote reservoir shocks and one of our SRC Scrambler subframes topped off with a gorgeous black leather seat with silver diamond pattern stitching. It was starting to come together.
The wheels were blasted and powder coated in silver an fitted with a set of Heidenau dual purpose tyres.
The electronics weren't scrimped on either. The old wiring loom went in the bin and a new much smaller custom one was made to mate up with the new Motogadget M-Unit, switches and full LED lighting.
New digital electronic ignition went on along with a new lightweight, lower geared starter motor and powered by a small, lightweight under tank Lithium Iron battery.
The tank is the focal point of the bike and that was treated to a bright pearlescent silver base coat and adorned with the colours of the German flag, with the black stripes being in 'carbon fibre'.
This little gem certainly has more bark and bite than the meek '45 it started life as, and Tim is certainly going to have lots of fun blasting around the roads of Kent where he lives.
If you'd like to see the finished article, pop along to the 2019 Bike Shed Show in London at the end of May where it will be on display with one of our other builds.
Side Rock Cycles