Why do SV's have engine braking?

I believe the gearbox gear ratios, front and rear sprocket size. Along with what was said previously in regards to engine piston size, piston rod length and compression ratio all have something to contribute to the back pressure equation.
Cheers!

there's a lot of factors engien braking is caused by the vacuum pulling against a closed throttle, compression affects its effect
flywheel weight/rotating mass affects the effect
# of cylinders affects the effect


sprotbike v twins have the most engine braking of anyting I have ridden, hardleys have less, cause ot their massive amount of rotating mass
inline 4's have less cause the vacuum is divided between 4 cylinders instead of 2 (not caust of the stroke, cause SV's, RC-51s Aproilla Vs etc have just as short a stroke as inline 4's and exaust back pressure has nothing to with it either

All bikes have engine braking, it just depends on how strong it is. The SV has some pretty rough engine braking for whatever reason. But, I think it is a good thing because then you can slow down without using the disc brakes.

I knew one of our American bro's would give us a text book explanationWell done Randy! I half expected leprechaun to dive right in to that one! Where is he by the way?

[ophic]

Originally Posted by RandyO

inline 4's have less cause the vacuum is divided between 4 cylinders instead of 2

can you explain why dividing the vacuum makes it less? it may be half the vacuum, but it occurs twice as often. According to my sketchy knowledge of Boyle's law (and I think Hooke's applies too) this should perfectly compensate. However its been a long while since i did physics.

Originally Posted by ophic

can you explain why dividing the vacuum makes it less? it may be half the vacuum, but it occurs twice as often. According to my sketchy knowledge of Boyle's law (and I think Hooke's applies too) this should perfectly compensate. However its been a long while since i did physics.

Not thinking too hard about it, but aren't the throttle valves still quite large so proportionally speaking there is less resistance to the gas flow.

I would think it's due to greater crank case pumping as Flamin_Squirrel said and probably more friction with two large long stroking pistons rather than four smaller short stroking. Rotational mass is higher than a IL4 which is the main reason for rear wheel lockups when changing down as the engine will not spin up as quickly.

Originally Posted by streetos

I would think it's due to greater crank case pumping as Flamin_Squirrel said and probably more friction with two large long stroking pistons rather than four smaller short stroking. Rotational mass is higher than a IL4 which is the main reason for rear wheel lockups when changing down as the engine will not spin up as quickly.

why do you think a twin has any longer stroke, sport bike 90° vees are not harleys , they have same oversquare ratios as inline 4's Sv bore & stroke is same as haybusa

I do think that the engine braking of an inline 4 at 12,000 rpm is similar to that of a twin at 6000 rpm.

Does a single cylinder 4 stroke engine of similar compression have more or less engine braking effect ?

I believe more is the answer.

My theory : More cylinders divide the compression and exhaust stroke across more piston cycles to achieve the same power out put. Kind of like 4 pumps doing the work of two or vice versa.

All I know is I love the gobs of engine braking of the SV650. Just curious how the SV1000 engine braking compares to the SV650. Has anybody rode both bikes to compare?
Cheers!