what to do with that stock muffler

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Humsuckler

Humsuckler

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any ideas? being as it does a fair amount of muffling.

i was thinking about throwing a pocket bike expansion chamber on my bike.
 
im actually quite pleased with just leaving the end cap off now after much trial and error lol

ill have to check the jetting tomorrow i did a nice high speed run and cut it out before i hit home
 
what i do to all my kits, i pull off the end cap, and cut the tube that is in it down so that it is flush with the cap, then put it in. it opens it up a bit,but still keeps it medium quiet.
 
cutting it flush with the cap made the powerband even worse.

no end cap FTW.
 
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so i tried this out just now, pulled out everything out of the stock muffler, end cap and all. its a lot louder now, but i rather like the sound, cant describe it, just sounds more "badass". the real benefit is the power increase, i get way better acceleration, and a higher top speed, before i had to struggle just to get it to 50kph, but now i actually have to restrain myself because it now goes 60kph and probably more, but i'll never know because my speedo tops out at 60kph...

my question is, how long before this starts having a negative effect on performance? is there a way to make it a bit quieter without losing the power gained?
 
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the only way i can see it having a grossly negative effect on the engines life is if you dont let it burble from time to time during full throttle runs (burble = letting off the throttle a little bit for a few seconds)

go for a run and get it warmed up, then when your on the way back home do a really good wide open max speed run and hit the kill switch while you pull in the clutch to cut it at full speed.

check your spark plug, it should be chocolate/coffee colored on the internal insulator. if its black black black and wet your too rich and if its a little light for comfort its too lean. you can fix it by moving the needle in the carbs slide either higher up in the slide, or to plunge farther down into the jet.

move clip up, it will sink the needle farther in the jet therefore leaning out the mixture. move the clip to the bottom and you will pull the needle higher in the jet therefore richening your mixture)
 
the clip is on the top slot of the needle, before i gutted the muffler the plug was a really dark brown/black, i checked the plug again after gutting the muffler and its sort of medium brown, not that dark and not that light. although i checked the plug after riding it normally. i took it for a ride again today and on the way back did the wot run then killed it, but didn't have time to check plug, gonna do it tommorow. how light can i allow the plug to get before its too lean?

10223d1246345156-how-read-your-spark-plug-acfkcapkayl1.jpg


my plug is a bit darker than the one in the middle, so im good to go without rejetting, right?
 
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2 strokes need some back pressure to run correctly, even tho it may run better , now you need some back pressure for the longevity of the motor and fuel mileage and keep the neihbors and the fuzz at bay.
 
filestyle is right, and so are you. your plug should be fine i wouldnt touch it but like i said ride it responsibly or your engine will die earlier.

when you "on the pipe" you know how it srats to burble when it revs out? you want to hold it burbling. dont force feed it mixture or you will be blowing out all your backpressure.

if that makes any sence to you, ride on.
if it doesnt, id suggest putting the end cap back on with about 5 or 6 holes drilled in its base instead of running an open header.
 
outlawbiker said:
um.................. yes they do.Two-stroke engine - Wikipedia, the free encyclopedia

File:Arbeitsweise Zweitakt.gif - Wikipedia, the free encyclopedia
Click to expand...

NO, they do not, that exhaust is an EXPANSION CHAMBER. The exhaust the comes with our engines is not, it is JUST A MUFFLER. The expansion chamber uses sound waves to help keep the mixture from coming out of the engine, our muffler that comes with is not it is only used to move the exhaust away from the engine and quiet it.... Your link doesnt prove anything. EXPANSION CHAMBERs are used to help the motor run better and create more power, so if you put a straight pipe on your HT it would gain power and be really loud


From the wiki below the picture:
"A two-stroke engine, in this case with a tuned expansion pipe illustrating the effect of a reflected pressure wave on the fuel charge. This feature is essential for maximum charge pressure (volumetric efficiency) and fuel efficiency. It is used on most high-performance engine designs."
 
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oh ok,you like to argue,so ill let you. but im not gonna listen. ive worked on small engines like this all they way up to big blocks, 2 cycles and 4, and even our little 2 cycles need some back pressure, so go right a head and try to run an open dump if you want,its not my engine,its yours. happy riding!
 
outlawbiker said:
oh ok,you like to argue,so ill let you. but im not gonna listen. ive worked on small engines like this all they way up to big blocks, 2 cycles and 4, and even our little 2 cycles need some back pressure, so go right a head and try to run an open dump if you want,its not my engine,its yours. happy riding!
Click to expand...

lol not trying to start a fight. I run my engine with an expansion chamber. .wee.
 
^ your not trying to start a fight, your just trying to educate. wrongly.

The muffler makes backpressure, an expansion chamber makes reverse amplified sound waves.... what do yo think backpressure is ding-dong.

let your pipe smoke that noob.
Having paid big dollars in education on small engines and paid many pistons on "thunkitworked's" i know, you are not as smart as you sound.....
 
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