Over the last year I have been using Duke22's 2hp single phase start rollers which weigh a ton, and tend to stall when I let the clutch out.
A few weeks ago I tried a set of rollers at a race meeting built with a 12V car starter - nope stalled these as well, and poor old Duke was reduced to a sweating mass helping me push start the bike - and even then we needed several goes on a slope to get any success.
Well, a few months ago I picked up a 24V Mitsubishi truck starter brand new off TradeMe (the NZ version of Ebay) for $75 and started figuring out an economical way to build my own set of start rollers.
During the last week of work in December I took advantage of the quiet week to drop into the local conveyor component supplier (Richmond Wheel & Castors) and picked up a 1500mm length of conveyor side, some spacers to hold the frame apart, and two 290mm width steel rollers.
Then it was over to the local bearing shop for 5 sprockets, some 1/2" industrial chain, a few assorted bearings etc, plus some other lengths so steel.
I had a gear made for the starter to mesh onto a month or so ago, so it was time to get building.
The Mark 1 version consisted of two roller on the same plane, a 24V 10 amp relay and a foot switch which only activated if you held it down.
I struck a few design challenges with this version:
1. The wheel was touching the starter motor solinoid and not the rear roller.
2. The two 12V batteries wired in series were not activating the relay properly - only a faint click. In my wisdom I by-passed the relay and wired the switch directly to the start motor and pressed the button and yep it worked, however 10 seconds later the 10 amp switch cried enough and the terminals welded themselves together - bugger.
So, for the Mark 2 version I got another length of conveyor side and added a second level, hunted down a automotive 24V 30 amp relay and got the auto electrician to do me a wiring diagram, and with the addition of some heavy gauge wire, new connectors and a new switch - SUCCESS.
The rollers spin the motor over easily in 4th gear and the ol' girl fired up immediatley
I still have to make covers out of perforated steel for the motor, chains and gears, and give it a lick of paint after tidying it up a bit more, but I'm well chuffed with the result. The other thing I'll do is get some non-slip conveyor roller covering and bond it to the rollers as the wheel is skidding in lower gears, and will be absolutley useless if it's wet.
