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It would run poorly, uneven firing intervals from that 180 degree crank means one cylinder will be getting less fuel/air mix.
 

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Cd 175 had a 360 degree crank, even firing intervals.
 
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each piston sucks in fuel/air as needed into the cylinder, as long as there is a sufficient supply of fuel. Why should it make a difference what the firing order of the pistons is? I have a CD200 with a single carb that runs perfectly, and I also have a Honda rebel clone with a dual carb, and the same model also comes with a single carb.
 

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Discussion Starter · #7 ·
each piston sucks in fuel/air as needed into the cylinder, as long as there is a sufficient supply of fuel. Why should it make a difference what the firing order of the pistons is? I have a CD200 with a single carb that runs perfectly, and I also have a Honda rebel clone with a dual carb, and the same model also comes with a single carb.
 

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each piston sucks in fuel/air as needed into the cylinder, as long as there is a sufficient supply of fuel. Why should it make a difference what the firing order of the pistons is? I have a CD200 with a single carb that runs perfectly, and I also have a Honda rebel clone with a dual carb, and the same model also comes with a single carb.
Hello, a 360 degree crankshaft twin will work OK with either 1 or 2 carbs. A 180 degree crankshaft needs a carb for each cylinder. The difference between the two is NOT the order of firing, it's the Degrees of Rotation between the events. A 360 crank fires once per revolution. BOTH pistons go up and down side by side. They go up and down together, side by side. When BOTH pistons are at Top Dead Center, both spark plugs fire, but only 1 cylinders fires, because one cylinder is at compression stroke, (and goes bang) the other cylinder is at exhaust stroke, has just blown out the exhaust. Both pistons go up and down side by side but only 1 side fires per revolution. That's why 360 crank engines use one coil with 1 set of points to fire both cylinders. That's called a wasted spark ignition, the cylinder on compression stroke fires, the other cylinder just pushed the exhaust out the pipe. A 180 degree crankshaft has 1 piston at Top and 1 at bottom. needs 2 coils, 2 points, 2 carbs. Lets say left cyl. fires, then crankshaft rotates 180 degrees then right side fires, after rotating ONLY 1/2 revolution (180 degree), now it takes 270 degrees rotation for left side to fire again, then 180 degree for right to fire again. That's why the different crankshafts cause a different sound from the exhaust. In Honda twins, the smaller, 125,160,175,200, 400T all have similar 360 degree exhaust note, while 250/305, 350, 360, 450,500T have a similar exhaust note, with ONE EXCEPTION, the CA77 DREAM, unlike the CB/CL 77, Superhawk, Scramblers that have 180 cranks, 2 carbs, 2 points, 2 coils, The CA77 DREAM has 1 carb, 1 coil, 1 points, because the low performance engine has 360 degree crank, which works well with 1 carb for lower performance engine, easier carb adjustment, timing, points ect. WHEN The difference in the timing of intake pulses is uneven (180 degree) it needs a carb for each cylinder for best operation. A twin with a single carb and 180 crank would run but uneven air/fuel ratio is likely compromise. The 360 crank makes for a simple balanced package that's more simple, however the Honda engineers clearly prefer the 180 degree crank for maximum performance. Hope this has made the issue easier to grasp to those not familiar with how and why theres a big difference between 180 and 360 degree crankshaft engines, the exhaust note is just the more noticeable part. Good luck, John
 

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Discussion Starter · #9 ·
Hello, a 360 degree crankshaft twin will work OK with either 1 or 2 carbs. A 180 degree crankshaft needs a carb for each cylinder. The difference between the two is NOT the order of firing, it's the Degrees of Rotation between the events. A 360 crank fires once per revolution. BOTH pistons go up and down side by side. They go up and down together, side by side. When BOTH pistons are at Top Dead Center, both spark plugs fire, but only 1 cylinders fires, because one cylinder is at compression stroke, (and goes bang) the other cylinder is at exhaust stroke, has just blown out the exhaust. Both pistons go up and down side by side but only 1 side fires per revolution. That's why 360 crank engines use one coil with 1 set of points to fire both cylinders. That's called a wasted spark ignition, the cylinder on compression stroke fires, the other cylinder just pushed the exhaust out the pipe. A 180 degree crankshaft has 1 piston at Top and 1 at bottom. needs 2 coils, 2 points, 2 carbs. Lets say left cyl. fires, then crankshaft rotates 180 degrees then right side fires, after rotating ONLY 1/2 revolution (180 degree), now it takes 270 degrees rotation for left side to fire again, then 180 degree for right to fire again. That's why the different crankshafts cause a different sound from the exhaust. In Honda twins, the smaller, 125,160,175,200, 400T all have similar 360 degree exhaust note, while 250/305, 350, 360, 450,500T have a similar exhaust note, with ONE EXCEPTION, the CA77 DREAM, unlike the CB/CL 77, Superhawk, Scramblers that have 180 cranks, 2 carbs, 2 points, 2 coils, The CA77 DREAM has 1 carb, 1 coil, 1 points, because the low performance engine has 360 degree crank, which works well with 1 carb for lower performance engine, easier carb adjustment, timing, points ect. WHEN The difference in the timing of intake pulses is uneven (180 degree) it needs a carb for each cylinder for best operation. A twin with a single carb and 180 crank would run but uneven air/fuel ratio is likely compromise. The 360 crank makes for a simple balanced package that's more simple, however the Honda engineers clearly prefer the 180 degree crank for maximum performance. Hope this has made the issue easier to grasp to those not familiar with how and why theres a big difference between 180 and 360 degree crankshaft engines, the exhaust note is just the more noticeable part. Good luck, John
Thanks.
 
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