Backpressure for 4 strokes

[jeffreykogan]

Hi, I have a 79cc predator (which is a 4 stroke) and I was wondering if having a bit of backpressure from a muffler would make it run better. I currently have it straight piped, should I switch it out for a different exhaust?

 

[Venice Motor Bikes]

A little back pressure is good for low end power; but having less back pressure helps the top end power.

I prefer less back pressure on all my 4-strokes... You can really help the low end power by actually pedaling the bike at low speed.

Another thing to consider is that when you add a straight pipe (& or a better air filter), you will also need to increase the jet size!

 

[zean]

...and you don't have to pedal very hard to get a noticeable difference in low end power.