Gyrobob wrote on 09/26/11 at 10:03:13:It can be placed just about as far away as you want. On some aircraft installations, the carb is feet away from the furthest cylinders.
On a motorcycle, you can't get it far enough away to make much difference. The mixture is traveling something like 50mph or so,.. around 70ft/sec. If the carb were 1 foot away from the intake valve, it would take 1/70th of second for the mixture to travel that distance.
The main differences from moving the carb away from the cylinder head would be thermal (the carb and manifold would stay colder), and intake tube resonance (longer tubes tune for lower rpm). This resonance can result in better torque/hp at lower rpm, but it is pretty hard to get the carb far enough away from the head to take advantage of this tuning concept. On the Savage, Suzuki just ignored it, placing the carb right on the head.
So on a motorcyle you woldent feel any differens in throttle respons unless you something other than human...
The backfire issue... how comon is that? I never heard about a exploding intake on a harley for example. And if there was a risk of backfiering the would be someone that experienced at least a small *poof-explosion* on there stock savage intake. Anyone??
If there were a risk of backfire in to the intake the must be some kind of release valve to place on the intake to save your "diamonds" in case of explosion right?
Would it work if I moved the carb down? And made an "S" shaped intake?
Oldfeller here .... please remember that Gyrobob is a helecopter/airplane person in a lot of his examples, and they get ramped up and down very gently and tend to be run at a constant speed. Our single cylinder bikes don't do that.
Our intake and exhaust streams totally start and stop their motion at the valves of the one cylinder, else where residual momentum keeps the air moving, moving relatively more steadily the further you get away from the valves themselves.
Bob's mental picture is of a multi-cylinder aircraft engine with a single carb set up on a manifold system, which is pretty common on small aircraft engines for maximum fuel efficency, ease of leaning/richening, reliability and ease of maintenance.
Next, an intake valve backflashes (backfires) whenever it does not close completely. Two ways to do that on our single cylinder bike.
1) a piece of carbon or trash on the intake seat -- pretty rare -- and
2) over revving and floating your valves -- this one depends on your wrist really. It happens to my bike pretty frequently.
Intake leakage (backfire potential) does eventually happen to all of us, I think you will just notice it a lot more than say mebbe I would.
( 
especially if that carb was maybe mounted sideways and happened to be aimed at your leg or your balls 
)
Pages: 1 
