by lordofthewings04 » Sat Sep 07, 2013 2:15 pm
Hi, this is an old thread but if you are still interested I can help. I have owned 2 Hurleman twins, and currently two singles and one twin. They are excellent engines but there are some things about the twins you need to know:
• Use 4:1 fuel (do not use more oil than that) and use SAE70 if you can find it -- try racing motorbike specialists. Filter the fuel – I use an inline filter before the fuel ever gets to the tank.
• Run on a 15x6 prop for best results.
• Starting is easy -- if you have lost the carb setting, go back to first principles and blow through the fuel feed tube (having removed the tank) until you just hear a hiss at the venturi -- mine were both 1-1/4 turn plus a couple of clicks. Get it wrong and the engines won't run, lean/rich is only the difference of one or two clicks.
• Be really careful that the prop driver/cam is in the right position or you will never get it to run – it is secured on a hex section on the shaft so it is easy to get it 60degrees out. Like all sparkies a rough guide is the points opening at tdc (remove the plugs first), full advance is with the timer arm vertical.
• After 40 years the gaskets at the c/case to cylinder join may have dried out or shrunk, if so make some extra paper ones to ensure the thickness is right, or you will have a wobbly cylinder/intake assembly.
• If you can find one, use a proper twin coil, or failing that one per cylinder – but a twin works best.
• Run-in really carefully, just 20 second bursts at first with plenty of cooling time between runs.
Enjoy !
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