The silencer - when its working and not commiting mechanical suicide is good for sound - sounds sorta a little deeper than a moped - specially when freewheeling/closed throttle...
but from what I have seen of the motor I only have very small finning on it - so where is the rest of the noise coming from?
Your GEBE 25cc, be it 4 stroke or 2, will be forced or fan cooled. Modern engines of this type will have thin, short, tightly spaced fins that would not benifit from these rubber inserts as an open or unshrouded engine would with its long, widely spaced, thick fins. The shrouding helps contain some noise BTW.
Mechanical noise will come out of both the intake and exhaust on both 2 and 4 stroke motors. In fact, exhaust sound comes out of a 2 stroke intake big time because both ports are uncovered for so long when the piston is at BDC.
In search of rubber ( ) I decided to cut up a torn up bicycle tire.
My evaluation:
It most definetly runs quieter and when I wind it out,it dosen't vibrate as hard!
Wow. This is like the simplest modification yet to a Happy Time that yields more Happy!
Just curious but would welding an aluminum strip vertically from the bottom of the cylinder jug to the top of the cylinder jug accomplish the same thing PLUS improve cooling since it is added surface area?....I will definitely try the rubber trick tho....just happen to have a spare inner tube sitting outside....
Thanks!
Just curious but would welding an aluminum strip vertically from the bottom of the cylinder jug to the top of the cylinder jug accomplish the same thing PLUS improve cooling since it is added surface area?....I will definitely try the rubber trick tho....just happen to have a spare inner tube sitting outside....
Thanks!
Welding would introduce warpage. Rubber will not effect bore dimention with expansion and contraction as the engine's heat cycle varies as a welded inplace bit of aluminum would. However...some engines have struts cast inplace with the cylinder at time of manufacture.
The rubbers used on motorcycle engines are very hard. I have some here for a Moto Guzzi project.