Gio Monster GY6 Performance Exhaust Review

Weldangrind · 07-14-2009, 12:07 PM

I bought a GY6 performance exhaust from www.giobikes.com and I would like to share the installation process.

First is a comparison between the new head pipe and the stock pipe. The new pipe was actually smaller, measuring 18mm (less that 3/4") in diameter. The stock pipe was 22mm (7/8"). Out came the die grinder to cure that.

The flange end where the pipe meets the muffler needed some minor cleanup as well. I ground the rough edges off and ported the inside to remove some welding bulge.

The stock mount location won't work with the new muffler, but you can use the rack mount with a longer bolt.

The new muffler has a perforated plate in the end that acts as a baffle. There are 15 holes in the plate that are 5/32" in diameter. The total surface area of all the holes equals 0.2876", whereas the head pipe area is 0.601". The perforations do create a restriction. I might do the calculations and drill them out later.

Overall, I'm pleased with the design of the new muffler. It essentially has a straight pipe with perforations inside that are wrapped in packing. Once the packing degrades, I can drill out the rivets and use new four stroke packing. Both gasket surfaces required some filing to ensure flatness, but not alot. The sound of the new pipe is noticeably more aggressive without being annoying.

suprf1y · 07-14-2009, 03:07 PM

Thats the exhaust we bought just for the muffler.
The plan is to remove that baffle plate, and put it on the beast 200.
Hopefully it'll be quieter than the homemade glasspack we have on there now

Weldangrind · 07-14-2009, 09:18 PM

Quote:

Originally Posted by suprf1y

Thats the exhaust we bought just for the muffler.
The plan is to remove that baffle plate, and put it on the beast 200.
Hopefully it'll be quieter than the homemade glasspack we have on there now

I had a similar thought about our Beast, since the photos on the Gio website lead me to believe that the Beast muffler is inferior to the Monster muffler.

If you remove the baffle, it will likely be as loud as what you have. The exhaust pipe leading to the muffler is the same OD on the Beast and the Monster, so the ID is likely the same. In that case, drilling out the holes with a 7/32" drill bit will produce a slight restriction, whereas drilling them with a #1 drill bit will remove the restriction completely, yet retain the baffle. If you don't have access to numbered drill bits, you could hog out the holes to 15/64".

Reveeen · 07-20-2009, 04:31 PM

The head pipe I got with mine was, as you say, "small". Suited, in my opinion, for a 50cc GY6 motor, and not a 150cc GY6 motor. The flanges were "bubble gummed" to the pipe.
The muffler was/is a poorly made effort, where the metal was formed in a press it was split in a couple of places, I'm guessing you can re-cycle Maxwell coffee cans only so far.
It did come complete with gaskets and a mounting clamp. It DID NOT come with any bolts (flange to muffler), the last couple of things (including bikes) from GIO were missing the bolts, and while not a "big problem", it's starting to get old, real old.

TurboT · 07-21-2009, 02:36 AM

W&G would you say you're getting better performance out of the new muffler, or just better sound?

Have you road/trail tested it yet?

Not that my daughter has much use for more power, but I wouldn't mind slapping the blue pipes for the 110cc he has on her's, just for kicks.

Weldangrind · 07-21-2009, 03:30 AM

Definitely better sound and power. Her quad no longer surges at the top end. I had previously installed a Uni pod filter and a fatter main jet, but the stock exhaust was the cork. I still intend to drill out the baffle holes to completely eliminate back pressure (in theory).

The GY6 muffler is a decent buy, because it is a straight pipe with perforations that are wrapped in packing. From the photos, the 200 Beast muffler doesn't look to be as free flowing; I can't speak for the 110 pipes, but they could be modified.

07-21-2009, 03:30 AM	#6
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Definitely better sound and power. Her quad no longer surges at the top end. I had previously installed a Uni pod filter and a fatter main jet, but the stock exhaust was the cork. I still intend to drill out the baffle holes to completely eliminate back pressure (in theory). The GY6 muffler is a decent buy, because it is a straight pipe with perforations that are wrapped in packing. From the photos, the 200 Beast muffler doesn't look to be as free flowing; I can't speak for the 110 pipes, but they could be modified. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

07-14-2009, 12:07 PM	#1
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Gio Monster GY6 Performance Exhaust Review I bought a GY6 performance exhaust from www.giobikes.com and I would like to share the installation process. First is a comparison between the new head pipe and the stock pipe. The new pipe was actually smaller, measuring 18mm (less that 3/4") in diameter. The stock pipe was 22mm (7/8"). Out came the die grinder to cure that. The flange end where the pipe meets the muffler needed some minor cleanup as well. I ground the rough edges off and ported the inside to remove some welding bulge. The stock mount location won't work with the new muffler, but you can use the rack mount with a longer bolt. The new muffler has a perforated plate in the end that acts as a baffle. There are 15 holes in the plate that are 5/32" in diameter. The total surface area of all the holes equals 0.2876", whereas the head pipe area is 0.601". The perforations do create a restriction. I might do the calculations and drill them out later. Overall, I'm pleased with the design of the new muffler. It essentially has a straight pipe with perforations inside that are wrapped in packing. Once the packing degrades, I can drill out the rivets and use new four stroke packing. Both gasket surfaces required some filing to ensure flatness, but not alot. The sound of the new pipe is noticeably more aggressive without being annoying. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

07-14-2009, 03:07 PM	#2
suprf1y Join Date: Oct 2007 Location: SW Ontario Posts: 408	Thats the exhaust we bought just for the muffler. The plan is to remove that baffle plate, and put it on the beast 200. Hopefully it'll be quieter than the homemade glasspack we have on there now
	0

07-20-2009, 04:31 PM	#4
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	The head pipe I got with mine was, as you say, "small". Suited, in my opinion, for a 50cc GY6 motor, and not a 150cc GY6 motor. The flanges were "bubble gummed" to the pipe. The muffler was/is a poorly made effort, where the metal was formed in a press it was split in a couple of places, I'm guessing you can re-cycle Maxwell coffee cans only so far. It did come complete with gaskets and a mounting clamp. It DID NOT come with any bolts (flange to muffler), the last couple of things (including bikes) from GIO were missing the bolts, and while not a "big problem", it's starting to get old, real old.
	0

07-21-2009, 02:36 AM	#5
TurboT Join Date: Sep 2008 Location: Surrey, B.C., Canada Posts: 2,185	W&G would you say you're getting better performance out of the new muffler, or just better sound? Have you road/trail tested it yet? Not that my daughter has much use for more power, but I wouldn't mind slapping the blue pipes for the 110cc he has on her's, just for kicks.
	0