balboa_71
New Member
Engine noise also comes from the intake piping because small industrial engines don't have the room for exotic intake baffling. Also look at the engine cases for noise as the ignition knock will be quiet loud when thin aluminum cases are used (all the time now). I have a 49cc Solex engine that sports a cast iron cylinder and decent air intake. Engine noise is low and the design allows for a small remote exhaust canister to be used which is great. Used to have a Tecumseh TC300 engine (49cc's) on a bicycle that had a nasty high pitched rattle coming from somewhere in the case, while this didn't effect performance, you could hear it from quite a distance; perhaps it was just piston slap. The big difference between 2 and 4 stroke engines with regard to noise is that with a two stroke, the exhaust port is exposted by the piston when it is still moving downward after ignition. Unburnt fuel excapes into the exhaust and there is a lot of shock/noise to go with it. One solution to this problem is to purchase a tuned exhaust (expansion chamber) that will use the noise to force some of the unburnt air/fuel back into the exhaust port. The down side is the tuned exhaust is quite loud!!! and also changes the power band. The 4 stroke engine pipes the exhaust out around the exhaust valve which starts to open near the bottom of the power/inition stroke, so it is much less noisey. It also goes without saying that the two stroke engine fires each crankshaft revolution, which adds to the noise.
If you are going to ride fast, go with a 2 stroke engine and find one that you can purchase a tuned pipe for, or have someone build the pipe for you. Expect there to be a lot of noise, but there is little that can beat a piston ported 2 stroke running high rpm. If you poke around and ride slow (like me) get a 4 stroke or low hp/low rpm two stroke engine and enjoy the ride. These last two suggestions will offer more torque and less headaches. Torque is the twisting force that pushes you down the road.
If you are going to ride fast, go with a 2 stroke engine and find one that you can purchase a tuned pipe for, or have someone build the pipe for you. Expect there to be a lot of noise, but there is little that can beat a piston ported 2 stroke running high rpm. If you poke around and ride slow (like me) get a 4 stroke or low hp/low rpm two stroke engine and enjoy the ride. These last two suggestions will offer more torque and less headaches. Torque is the twisting force that pushes you down the road.
