The idea of the portable dyno came from a friend, John Horton who I met at the bonneville salt flats during Speed Week. He new of a fellow racer, a professional kart racer that designed and built a hydraulic dyno. The dyno was small, portable and used in the pits to fine tune his karts often between races and he was 'very successful', the idea sounded good to me.
The primary parts; used hydraulic pump and drive system, needle and relief valves, hydraulic tank, a cooler and pressure gauge(s).
Although the kart guy used a chain drive direct from the crankshaft of his test motors to connect to the pump it was suggested that I use a separate drive roller (thanks for the idea John Hanson) and this idea would allow quick set-up and also allow my team mate to run his Honda on the dyno too, a win-win situation
Because of the high temps on the salt and a small capacity reservoir I decided to add a heat exchanger to keep the hyd. fluid temps from getting out of hand. Swing-out stabilizers were also incorporated due to the narrow frame width (necessary to slide in the side door of my travel trailer) and to prevent a 'Tommy Tip-over' while running a scooter which would be very embarrissing. The drive wheel is a new Goodyear 5.00-5" aircraft tire which I feel should be good for at least 120mph before funny things start to happen!?
Anyhow, this is what happens when guys get together in the pits and/or shops and start thinking and discussing ideas. Since I started this build I have found similar commercial hydraulic dynos used in the outboard motor shops that connect a basic pump (w/pressure gauge) directly to the outdrive shaft (in place of the prop) and use a conversion table pressure vs. H.P.
I still need to diassemble,finish weld and paint (to match my bike) then TEST this thing ..... and make changes if necessary!
George McMurray, Tri-Mac-Speedsters, LSR race team
but..... it's a very durable urethane and looks like powder-coat when it sets-up. The only real drawback is it's available in 1 gallon kits only and it's a little spendy although not as bad as automotive stuff. I need something that holds up to the salt envirnonment and IT DOES!
