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General => General Discussion => Topic started by: blue on August 13, 2014, 08:35:20 PM

Title: drilling holes in muffler.
Post by: blue on August 13, 2014, 08:35:20 PM

I have seen were they drill holes in the back of the muffler around the main hole.is that for take off speed or for top end.and is ok to do.with out harming the scoot.

Title: I did that to a motorcycle
Post by: boo on August 13, 2014, 08:50:06 PM

years ago.
Performance difference is negligible.
Will sound a little louder is all.

Title: Re: drilling holes in muffler.
Post by: Porkie on August 13, 2014, 09:47:22 PM

I HAVE HAD VERY GOOD RESULTS WITH DRILLING, AROUND THE MAIN OUTLET, ESPECIALLY ON MY PAST DL1000 SUZUKI V-STROM AND MT PAST DUCATI 900SS. THE RESULT SOUNDED ALMOST LIKE A THOUSAND DOLLAR EXHAUST SYSTEM. MORE POWERFUL, WHO KNOWS BUT PSYCHOLOGICALLY IT WAS WAY MORE FUN. JUST DON'T OVER DO IT. START WITH MAYBE 4, 3/8 INCH HOLES, EVENLY SPACED AND THEN ADD MORE HOLES. DON'T CHANGE THE AIR FILTER OR WITH THE MODIFIED EXHAUST AND THE HIGH FLOW AIR FILTER YOU MAY HAVE TO REJECT (CARB) OR RECALIBRATE THE ECM (FUEL INJECTION.)

SAM:)

Title: Re: drilling holes in muffler.
Post by: blue on August 13, 2014, 11:49:04 PM

If its not going help in speed.ill just leave it be.

Title: Re: drilling holes in muffler.
Post by: mrbios on August 14, 2014, 04:11:37 AM

Quote from: blue on August 13, 2014, 08:35:20 PM

I have seen were they drill holes in the back of the muffler around the main hole.is that for take off speed or for top end.and is ok to do.with out harming the scoot.

Don't do it.  Remember, to gain any power you must change the air filter & rejet (or chip with EFI).  The max that can be gained is 10%  but usually much less.  Also, reducing back pressure can result in a loss of power.  Case in point - my exhaust bolts were not tightened all the way and the fell off on the highway and a slight space developed in the exhaust making it much louder.  The power dropped by about 30%!

On little 50 & 70cc scooters it can be easier and sometimes owners buy a kit - aftermarket air filter, pipe, jets etc which makes it easier.  Two strokes can get see a noticeable power improvement.  Mostly it is just noise and reduce resale value.  No one wants to buy some else's jetted junk.  Many rejets aren't even done correctly.  Most rejets / chip (EFI) run too rich to avoid damaging the motor which junks up the engine & oil and the air with excess carbon & pollution.

Want more power - sell it and move up to a 250 or 300cc or...