2mph increase in about 5 mins

[kidd778]

all i can say about it is that out of fun i took the insides and the end off the muffler and the throttle response was more crisp on lower end but no more top end and it was VERY VERY loud

 

[Junster]

all i can say about it is that out of fun i took the insides and the end off the muffler and the throttle response was more crisp on lower end but no more top end and it was VERY VERY loud

It wasn't the muffler insides the first poster was talking about. For a while the motors came with a Supposedly "catalytic converter" to try and skirt the Cal. carb laws. Like a earlier poster said palladium, platinum. Those are what makes a catalytic converter work. They collect the baddy's then as you reach a higher temp burn them up. (the rotten egg smell going up hill at higher speeds in traffic) The chinese aren't supplying real cats in motors that wholesale fob china for less than $50 bucks. As far as the pollution goes? Better quit mowing your grass then. Mowers in the US are making 1000x more than the few bikes around.

 

[rustycase]

here in Kalifornia they sell 'catalytic converters' for peoples wood burning stoves...

it's a section of the pipe that holds a waffle lookin' cast iron grid thing that probably ends up glowing red hot a vaporizes some of the gases that escape the box unburned...

I dunno...

the local FD gave me a citation becuz my boys had a bbq in the back yard.
Go figger.

Believe me, it would be REAL difficult to go to court and go up against a fire man.

rc

 

[Junster]

If you gotta have some more speed then throw some money at your bike. Shift kit, tuned pipe, carb, HC head, tires that can handle it. Do a really good job on the installs and say goodbye to easy starting dependability. Be smart go with the pipe and jet up a little to match it. Biggest power for the buck and still easy starting bike. I ended up with over $900 in my bike to get it to 42 mph real speed flat ground clocked with a gps 220 lb. rider. Was it worth it? For a while then the bike ended up put away cause there was nothing left to do to it and it would slowly tear it self apart. It was alot more fun and better when I assisted the steeps with the pedals and just crusied. Put on over 2k miles one summer that way, did maybe 500 after I was cool and fast.

 

[Junster]

Yup catalysing the smoke as it is forced thru the ceramic. It does reduce the wood smoke output. BBQ ticket? was it a no burn day? Did they offer up a beer? That stinks.. Only way these bikes are going to stay around is for somebody to streamline a 4 cycle design. Probably with a dry sump motor. Cause the only cool factor is with a in frame mount.

 

[motor_bike_fanatic]

Here is the deal. If you take a stock muffler and tear all the guts out and dont put the end cap on, you will have a straight pipe. it will put out more power for a little while, but eventually it will screw up your port timing and you will lose power. After that it will just burn up your rings. However, if you take the guts out and put the end cap back on, you basically have a poor man's expansion chamber. The reason why they call it an expansion chamber is because at the wider part, the gases expand. Then they bounce off the cones and return to the engine. Well, in a gutted stock muffler, the gases bounce off the end cap. I used to run a pipe like that till I modded a pocketbike pipe. It worked pretty good, and wasnt that much louder. I didnt retune my carb when I had that pipe, so I dont know what my air/fuel mixture was like. Had I retuned my carb, Im sure I could have gotten it right. Since I modded the pocketbike pipe, I have retuned my carb, so my air/fuel mix is right. But there is nothing wrong with modding a stock pipe if you do it right. it isnt that much louder, and it wont hurt your engine at all.

 

[Highwaystar]

Here is the deal. If you take a stock muffler and tear all the guts out and dont put the end cap on, you will have a straight pipe. it will put out more power for a little while, but eventually it will screw up your port timing and you will lose power. After that it will just burn up your rings. However, if you take the guts out and put the end cap back on, you basically have a poor man's expansion chamber. The reason why they call it an expansion chamber is because at the wider part, the gases expand. Then they bounce off the cones and return to the engine. Well, in a gutted stock muffler, the gases bounce off the end cap. I used to run a pipe like that till I modded a pocketbike pipe. It worked pretty good, and wasnt that much louder. I didnt retune my carb when I had that pipe, so I dont know what my air/fuel mixture was like. Had I retuned my carb, Im sure I could have gotten it right. Since I modded the pocketbike pipe, I have retuned my carb, so my air/fuel mix is right. But there is nothing wrong with modding a stock pipe if you do it right. it isnt that much louder, and it wont hurt your engine at all.

Good post. There are so many misconceptions on how a chamber effects performance. My other hobby is 1/5 scale rc. Trying to squeeze 5+hp out of a 26cc engine, a pipe is your best friend or your worse enemy.

 

[Drewd]

I'm guilty with unnecessary extra noise by using a SBP tuned pipe. I never realized how annoyingly loud the tuned pipe was until I let someone ride my bike up and down the street in front of my house. I'm eventually going to switch to a poo poo pipe and regear so I can maintain hill climbing ability and not care about top speed as long as I can get 25mph out my setup. I want to be able to hear gear whine over exhaust noise again.

 

[BarelyAWake]

SBP expansion chamber w/custom header & silencer;


The stock silencer is simply a glasspack, you can drill out the four pop rivets & make your own glasspack silencer at w/e length you wish using 2" aluminum conduit, heavy gauge steel screen & fiberglass mat (house insulation works too). As it's after the expansion chamber & you're not reducing ID, there's no performance loss.

Add some header wrap for the final touch