OK so the boyer sachse etc.. ignitions don't run any manifold or throttle position sensors, therefore you'd assume that with those units the bikes' timing curve will run exactly as it would with the vac-unit disconnected where the timing curve is controlled by the centrifugal unit(engine revs) only? I'd say they'd have a quicker response or beefier spark though
PS just looked at a vid on the .com site, basically shows me what I''ve been telling everyone forever, that is the vac unit runs exactly the same when connected at a sync port or the carb port. Only difference at shut throttle on over-run the carb port switches off with the stock connection. I can tell them that out on the road full advance at shut throttle over-run will have their bikes running great. . Shutting off the advance must be just another nuisance emmissions restriction
The guys there also claiming that at idle on a sync port the timing advances. At normal idle, as in sitting stationary that's true, by 5 degrees, but doesn't the stock carb hose connection do the same when connected at those low revs? I can't tell as I haven't got the stock carbs on my bike.
I'd say the few degrees advanced at idle would be a desirable thing, notice the boyer etc.. ignitions claim to advance the idle for a better low rev response. Once the revs creep up, and the air gets flowing, the vac unit begins operating off the manifold vacuum as normal, checked with a timing light it's plain to see. On mine, removing the vacuum at idle drops the idle speed by around a hundred or so revs. The 5 deg advance actually gives a smoother and stronger idle.
QUOTE:
"Stick a restrictor like an old idle jet in the vacuum advance line and run the advance line off the manifold boot.."
"It works but it works backwards at some critical times" BOLLOCKS
" there is ignition advance at idle" TRUE, 5 DEG BY TIMING LIGHT, BUT MEANINGLESS AND LIKELY AN IMPROVEMENT OVER STOCK
"full advance on overrun" A GOOD THING IF YOU HAVEN'T BEEN SUCKERED BY GREENIES AND THE GREAT GLOBAL WARMING CON
"no advance at part-throttle lean" BOLLOCKS, NO DIFFERENCE
It's all nowhere near as complicated as they're making out, the vac unit runs off the manifold vacuum, that's all there is to it. Simple Simple. The hose connection at the carb is only there to make the butterfly shut down the vacuum supply when closed. If the carbs are roughly set at a high idle or unbalanced, it won't even apply anyway, because the notch on the butterfly gives vacuum back with the very slightest of throttle movement. The vac inlet always sits on the manifold side and everything's still all running from the same bloody vacuum, there's no other magical vacuum coming in from some other mysterious source. heheh
