cobrafreak
New Member
- Local time
- 2:51 AM
- Joined
- Oct 13, 2010
- Messages
- 20
This is probably old hat to most of you, but it could be helpful to some.
I have been looking for a bit more run ability and power and I found a simple,quick and cheap way to do it. I made a drawing:
http://i32.photobucket.com/albums/d37/jperickson2001/motorbike/IMG00304-20110109-1433.jpg
I reasoned that the hole coming out of the engine is much larger that the one going out of the muffler, thus creating a restriction. I measured the existing exhaust hole at 13/16". I simply drilled another 13/16" hole next to it. WOW! Significant power increase, especially low end power. The response is better. Climbing up hills is no problem at all. The exhaust flow coming out of the engine now is so much greater that it was necessary to move the carb needle valve clip all the way down to the bottom so the needle is at the uppermost position. After all, the fuel being burned is what is making the power. More fuel burning, more power. If you don't move the clip down/needle valve up you wont make any gains. The sound is louder, but not too loud. Much louder if you remove the entire bottom of the muffler off. I measured it at idle at 90 - 92 db. Putting around the neighborhood slow is not too loud. Getting on it is a little louder. loud enough for me to wear ear plugs because I don't like too much noise. You make the call on this. I think the trade-off is well worth it. If you don't like it you can always weld the hole back up or put a bolt and nut in it to plug it up.
I have been looking for a bit more run ability and power and I found a simple,quick and cheap way to do it. I made a drawing:
http://i32.photobucket.com/albums/d37/jperickson2001/motorbike/IMG00304-20110109-1433.jpg
I reasoned that the hole coming out of the engine is much larger that the one going out of the muffler, thus creating a restriction. I measured the existing exhaust hole at 13/16". I simply drilled another 13/16" hole next to it. WOW! Significant power increase, especially low end power. The response is better. Climbing up hills is no problem at all. The exhaust flow coming out of the engine now is so much greater that it was necessary to move the carb needle valve clip all the way down to the bottom so the needle is at the uppermost position. After all, the fuel being burned is what is making the power. More fuel burning, more power. If you don't move the clip down/needle valve up you wont make any gains. The sound is louder, but not too loud. Much louder if you remove the entire bottom of the muffler off. I measured it at idle at 90 - 92 db. Putting around the neighborhood slow is not too loud. Getting on it is a little louder. loud enough for me to wear ear plugs because I don't like too much noise. You make the call on this. I think the trade-off is well worth it. If you don't like it you can always weld the hole back up or put a bolt and nut in it to plug it up.
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