Emil's miniature EML model
Emil Bollhalder’s miniature 1983 EML sidecarcross chassis
Check out this incredible model of two-time World Sidecarcross Champion Emil Bollhalder’s 1983 EML sidecarcross chassis, hand-built by South Australian John Turner.
It was built to quarter scale and weighs approximately 3.5kg. The overall dimensions are approximately 540mm x 340mm and 240mm in height.
John Turner, who raced sidecars himself, personally presented the model to Emil Bollhalder in Switzerland in 1986 – having met him in Australia in 1984 and after building the model, which he estimated took 1,500 hours over a two-year period.
At the time, Bollhalder was the reigning 1982-83 World Sidecar Champion and had just retired from World Grand Prix racing.
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Video – Emil Bollhalder in action at the 1984 Western Classic, Noble Falls in Western Australia.
Bollhalder’s tour down under
Emil Bollhalder at the 1984 Western Classic in WA at Noble Falls, with South Australian passenger Russell Ellis
After racing at the King of the Cross and Western Classic in Perth in August, Emil travelled to his next event in South Australia where he stayed with John Turner’s friend and another sidecar rider – David Wells.
Wells raced in Europe against Emil and became friends.
When David introduced John to Emil, John showed him some models he had been working on, including a radio-controlled road-racing sidecar that he had designed and built himself, plus a motocross sidecar that he was working on.
Emil was very impressed and asked John to make him a model of his Yamaha EML motocross sidecar, which he agreed to.
Before Emil left Australia, he gave John a large block mounted poster of him in action and personally signed it “To my friend John, the model bikes engineer”.
Turner begins the big job
Someone who always delivers on his promises, John started planning the build immediately and in October that year he got the measurement’s from Western Australian sidecar passenger John Steyntjes’ EML chassis, which was the latest 1983 model and the same as Emil’s.
John’s rider Mick Wimmer was injured, so John planned to team up with David Wells for the Australian Championships in Broadford, Victoria. They planned to ride David’s 998cc Yamaha EML in the Unlimited class and John’s Yamaha EML in the Juniors, switching his 998cc Yamaha with a Yamaha 500cc engine.
With the measurements he needed, John Turner started building the model and worked on it relentlessly for the next two years.
At the time John was a boilermaker welder, who had acquired a few basic mechanical machine shop skills through an apprenticeship and at night school and was not a fine-scale model engineer.
John and his wife had been planning to travel to Europe in 1986, so he completed the model in time for the trip and personally presented the sidecar to Emil at his home in Switzerland, as a gift.
John said that there was a small drama while travelling.
“When we arrived at Heathrow airport, I couldn’t find the model on the carousel and I started to panic,” he said.
“But I eventually found it on a trolley with ABC television camera equipment.
“Unbeknown to us, we were on the same flight as the ABC sports team going to Edinburgh for the 1986 Commonwealth games and the model got mixed up with their gear.
“When we arrived in Lutisburg, Switzerland, Emil met us at the station and we spent the night at his home.
“The look on his face when I took it out of the box and assembled it was priceless!”
See below for photos and John Turner’s description on how he built the model EML.
John Steyntjes’ 1983 EML chassis, which John Turner measured to make Emil Bollhalder’s miniature sidecar.
The finished product. It took over 1,500 hours to build over two years.
Left: Tank plug and mould; Centre: Sidecar mudguard plug and mould; Right: Split moulds for the three wheel rims and two rims that failed quality control.
The build (By John Turner)
- I had some jigs and fixtures in place from my first attempt at building a sidecar.
- The model is mostly 1/4 scale, the main exception being the fasteners, these are predominantly 3mm socket head cap screws, which in reality scale up to 12mm.
- The basic overall dimensions were (based on my own model) approximately 540mm long x 340mm x 240mm high and it weighed approximately 3.5kg.
- This scale was chosen as there were some COTS (Commercial Off The Shelf) items available for the bike, and I had bought front and rear wheel kits from a solo radio controlled bike and other items, which had handlebar grips and other parts I could use. But the rest I had to hand make.
- The greatest challenge for this build was definitely the wheels.
- The COTS wheels were nothing like the real thing so I bought the spoke kits and tyres but made hubs and rims as close as possible to the real thing.
- The hubs were relatively easy with the drilling of the spoke holes the only time consuming bit, setting up the dividing head to get the correct spacing, all dimensions for the hubs were taken from your bike.
- The rims were a different matter, I thought about turning them from alloy billet but would then have the problem of having no spoke dimples. So I opted for making split dies from alloy billet and dowelling them together, then machining the profile of the rim equally spaced about the join line. Then with a tiny ball end cutter in the milling machine and the dividing head, I positioned the dimples 20 on one side and reset the head angle on the other side of centre – achieving the 40 spoke dimples in each rim jig.
- To maintain concentricity of all three wheels I made a mandrel which was turned parallel and centre drilled both ends for turning between centres. I then applied a red jell coat to each rim mould and overfilled the remaining profile with fibreglass, when properly cured I was able to turn to diameter and then turn the profile to suit the profile of the tyres.
- At this point I removed the rims by splitting the moulds and had some reasonable looking rims but still had to drill through the spoke dimples, so back in the dividing head and mill, this was relatively successful but a couple of the dimples broke away.
- So with 3 rims and 3 spoke kits, David Wells spoked the wheels for me. He did a fantastic job and I was able to fit the front and rear tyres.
- The next problem was to find a suitable tyre for the sidecar wheel. I had a friend who was a manager at a model shop and contacted him and he said to bring the wheel in and he brought out a selection of returned kits, which had parts missing, and we eventually found a tyre that fitted solving the problem.
- The frame was straight forward enough and was made from bright mild steel bar and the spine was tube. All brackets were made from 1.6 mild steel sheet and the whole lot bronze welded together. I had to compromise here as the EML was MIG welded but I didn’t have a micro MIG welder. Much fettling was done with needle files before it was off to the electroplater for Chrome plating.
- The front, rear and sidecar mudguards were also fibreglass and I obtained the profile by turning discs of wood in the lathe and from those “positives” made fibreglass moulds and from those “negatives” made the final products using red jell coat and glass fibre mat, more care had to be taken here as there was no final machining of the underside surfaces.
- The petrol tank was made in the same way and is hollow if looked at from underneath. Side covers and number plates were made from ice cream containers.
- The seat was a flat plate with foam rubber stuck on and shaped and I got some white and red vinyl offcuts from an upholstery shop and glued the pieces together.
- The shock absorbers were made from alloy rod with the tops being turned to a ball end, then the flats milled and drilled for the fasteners and the circlip grooves added. The shafts were made from silver steel and the bottoms were made similar to the top and screwed onto the shafts.
- The shock absorbers were not oil tight, so they had no damping. But the springs were adjustable by moving the circlip up or down the body. All springs were COTS.
- The brake discs were cut from 1.6 ms sheet and turned to the finished diameter. The slots were measured from the originals and drilled and filed to shape. When completed the discs were set up in a drill press and the centres were pushed down to achieve the correct offset.
- The brake calipers were fettled from alloy plate to “look the part” but not at all functional. The caliper brackets were from ms sheet – measured from the original, then cut to shape and offset accordingly.
- The steering damper was COTS brass tubing which is made to be telescopic with the ends taken from a COTS shocker from a scale model car, just stuff I had in my parts box.
- In addition to making the model I then had to make a carry box, this was made from 1.6 alloy sheet and 25mmx25mm alloy angle with 50mm foam padding on all internal surfaces, the wheels were removed for transport.
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