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Hi All,

I have a 2007 Royal star tour deluxe and I decided to switch out my Bubs slip-on mufflers as the tips were beginning to look a little ratty. I bought a set of Sharkroad megaphone slip ons from Amazon that fit a Road King so I figured they'd fit my bike. They fought a little bit after cleaning the exhaust pipe connection with some sandpaper to get the corrosion and crust off, plus some WD-40 as lube, I got them on. When I had the Bubs on the bike she would backfire, she still does it with the Megaphones on it only louder (I loved the Bubs, but the Megaphones sound AWESOME) I want to stop or at least reduce the backfire. Did anybody put these on their bike and have the same issue? How to fix it???
 

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Kman4443, Welcome from Sacramento, Ca. If you post in New Member Introductions we could get to know you better. I am the wrong guy to ask about backfire I like a little bop bop upon deceleration.
 

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Hello from Palmyra. New York When I changed my pipes I had a bad popping on deceleration. I have a Road Star with a fuelpak so it was pretty easy to fix. Sorry I am no help.
 

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2000 Yamaha Royal Star Venture
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There are a few things that contribute to..or cause..the backfire. Check the vacuum ports on the carbs (in the "V" between the cylinders). A stock setup usually has 2 of the little tubes capped by a rubber plug, with small rubber hoses connected to the other 2. All 4 might be plugged with the caps, or as I did with mine the caps and hoses are removed completely and a short piece of rubber tube (approx 2 inches) connects the ports on the carbs on each side to each other....left front to left rear-right front to right rear. There are those who figure that the hoses are connected to the Cruise Control. I can only speak for my own bike but they aren't. Cruise works fine without the hoses. Just leave them hanging in between the cylinders, or zip-tie them to something if it matters. Either way be sure all the ports are connected or blocked.

When I first got my bike (gently used 2000 RSV) it backfired and popped under any form of deceleration. The vacuum port tweak I described above made it slightly better, but what I found to be the main culprit was the AIS setup...basically a pollution control system. There are 2 small air boxes in the system...1 mounted behind and slightly left of the bottom of the rad. The other is under the right side of the bike near the rear shock. Both have a large diameter rubber hose (1 inch??) attached and I discovered that the front air box had broken off the mounting bolts and was letting air into the otherwise closed system. I plugged the hose with a piece of wooden dowel and hose clamped it tight. The rear air box was intact, so I removed the hose, sealed the pipe with duct tape, and re-installed the hose, again using a hose clamp. The backfires are gone...not just lessened, gone. The only time I heard a slight popping in the exhaust was shortly after joining the carb ports together. I had used some clear vinyl tubing and due to the heat of the engine they had deformed to the point of being loose, which let air into the ports. They were replaced with rubber gas line hose zip-tied onto the vacuum ports. Problem solved.

One other cause I've read about is in the exhaust pipe itself. On the "Y" pipe that connects the rear cylinder to the front pipe, at the junction of the "Y", the pipe might be rusting out. REALLY thin metal and not for the faint of heart when welding, but extra air getting into the exhaust there might create the popping sounds.

Check the carb vacuum ports buy or borrow a good carb synch rig (or have a shop synch them...easy to do yourself...save the $) and check the AIS. Check, as in disable it. The fraction of a percent of extra deadly exhaust you'll create without it will be balanced out by all the new Teslas on the road.

Hope this helps...
Cheers.
 
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