Performance Exhaust Loud and Slow

skyrider · 10-12-2014, 12:02 PM

Just got a $180 stainless performance exhaust and uni dual filer for my QMB139, and with a new gasket or old gasket, its loud and I have no power. It barely gets to 25. ( I was getting 40 on a flat rd with 200lb. of me.) Took out the carb and there's a big hole in the main jet so I guess its letting enuff air in but I'm ready to paint my old muffler and sell the exhaust since I can't return it. My regular setup was perfect power for me, variator set to get my heavy ass up hills, I just was tired of looking at a rusty old exhaust.

So is there anything else I should do to get more power and quiet before selling? (Please Pm me if you want a new exhaust)

dwint51 · 10-12-2014, 05:04 PM

you sure your exhaust is on right at the head

skyrider · 10-12-2014, 08:13 PM

yes. I first used the gasket kit that I got that is one piece but a hole on each end for the 2 connector bolts. Then I used the round gasket that is origional equippment. Same result. I'll double check tomorrow.

mmsscooters · 10-12-2014, 09:43 PM

it might be the air filter, you cant just add a performance filter to a stock carb, you will be too lean

skyrider · 10-12-2014, 10:26 PM

when I told partsforscooters I got no power from the performance exhaust they said I would need to get that particular air filter and get a bigger main jet and adjust the carb, they mentioned nothing about a different carb. So do I need another carb, which kind? Also, what I did was put the exhaust studs in halfway, then got some red silicone and put that around the gasket to hold it on then put the exhaust head on the two studs then tightend them down. So they should be tight and I know the gasket is in. Also, are performance mufflers louder than stock??

skyrider · 10-13-2014, 07:25 PM

thanks for all the help! I finally spoke with the owner of Partsforscooters, and he said use my stock air filter(like mmscoot) said. Now the new exhaust is quieter than my stock exhaust and I finally have my power almost back. Not quite sure if it accelerates as quickly and haven't run it on long enough straight to hit 40 but I'm sure it can. Would a 85 main jet help???
Second problem: last week I finally took off my rear tire cause the brakes were squealing always when I put the brakes on. I found transmission fuel on the pads and inside, and my local shop guy said to replace the pads and that the trans seal was bad. So I put new pads on. There has always been trans fluid on the crankcase side of the wheel. He said the budget way to fix it would be to put black silicone around the inner axle, that the fluid was entering the drum around the axle. I put the silicone in, waited overnight, but it still squeals. What to do next for the brake??? thanks in advance!!

kz1000st · 10-14-2014, 07:00 AM

Did you sand the glaze off the brake shoes when you had it apart? If you lightly sand off the glaze from the shoes and the drum the problem should stop.

skyrider · 10-14-2014, 08:20 AM

I should have sanded vs put new pads on? Well anyway, now my new pads have the same squealing sound. So take the tranny apart and put a new seal on?? Anyone have a link to a youtube on how to do that?

skyrider · 10-21-2014, 08:35 AM

Follow up: Decided that with my 2012 Quinqui it performed better with the stock exhaust than the performance exhaust, even with changing out the main jet and running the performance with a performance air filter and stock air filter. Just noticable power with stock all the way. Still some rear squealing from the brakes after sanding both drum and brakes and cleaning with brake cleaner. But the silicone around the axle I put on stopped any more trans fluid from leaking in.

10-12-2014, 09:43 PM	#4
mmsscooters Join Date: Feb 2014 Location: las vegas Posts: 100	it might be the air filter, you cant just add a performance filter to a stock carb, you will be too lean __________________ 2012 Jonway X 44mm Hoca crank 52mm Hoca big bore MMS big valve head raised ports, polished, milled .023 Hoca 26mm carb NCY titanium valve springs NOS wet nitrous system Holley fuel pump MMS variator Naraku CDI HT coil 4' Wheelie bar MMG stainless slip-on exhaust NGK "11" spark plug UNI filter 2014 Icebear Maddog too much to list http://mmsscooters.com
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10-13-2014, 07:25 PM	#6
skyrider Join Date: Jul 2013 Location: richmond,VA Posts: 94	thanks for all the help! I finally spoke with the owner of Partsforscooters, and he said use my stock air filter(like mmscoot) said. Now the new exhaust is quieter than my stock exhaust and I finally have my power almost back. Not quite sure if it accelerates as quickly and haven't run it on long enough straight to hit 40 but I'm sure it can. Would a 85 main jet help??? Second problem: last week I finally took off my rear tire cause the brakes were squealing always when I put the brakes on. I found transmission fuel on the pads and inside, and my local shop guy said to replace the pads and that the trans seal was bad. So I put new pads on. There has always been trans fluid on the crankcase side of the wheel. He said the budget way to fix it would be to put black silicone around the inner axle, that the fluid was entering the drum around the axle. I put the silicone in, waited overnight, but it still squeals. What to do next for the brake??? thanks in advance!! Last edited by skyrider; 10-14-2014 at 08:17 AM.
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10-14-2014, 07:00 AM	#7
kz1000st Join Date: Oct 2008 Location: Hyde Park, NY Posts: 1,062	Did you sand the glaze off the brake shoes when you had it apart? If you lightly sand off the glaze from the shoes and the drum the problem should stop. __________________ 2008 Eagle Milano 150- 9,679 miles 2009 Honda Rebel 250- 10,434 miles 2009 CF Moto Fashion- 16,023 miles 2009 MC-114 50cc Cub Clone- 4,317 miles twowheeler.yolasite.com/ That's 30,049 China Scootin miles and Counting.
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10-12-2014, 05:04 PM	#2
dwint51 Join Date: Mar 2013 Location: murphy n.c Posts: 467	you sure your exhaust is on right at the head
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10-14-2014, 08:20 AM	#8
skyrider Join Date: Jul 2013 Location: richmond,VA Posts: 94	I should have sanded vs put new pads on? Well anyway, now my new pads have the same squealing sound. So take the tranny apart and put a new seal on?? Anyone have a link to a youtube on how to do that?
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10-21-2014, 08:35 AM	#9
skyrider Join Date: Jul 2013 Location: richmond,VA Posts: 94	Follow up: Decided that with my 2012 Quinqui it performed better with the stock exhaust than the performance exhaust, even with changing out the main jet and running the performance with a performance air filter and stock air filter. Just noticable power with stock all the way. Still some rear squealing from the brakes after sanding both drum and brakes and cleaning with brake cleaner. But the silicone around the axle I put on stopped any more trans fluid from leaking in.
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