Backfiring after sync

[YamaGeezer]

Hi all. I have a 2007 Venture and wanted to ask a question:

 

I've had the carbs synced 2 times in 9,000 miles. Both times they were synced, I start getting a backfire out of the right side exhaust when decelerating (in gear). Never the left side, always the right.

 

The bike hasn't backfired since I ran a bottle of Seafoam in it earlier this summer. Had my 8,000 mile service done today. On the way home, it's backfiring again!

 

What are your thoughts? It's not bad, but I prefer it not to backfire. I had the dealer service dept. look for an exhaust leak the last time. I've tried to find one as well, but there just doesn't appear to be a leak. Is this something any of you have experienced?

 

Thanks....

[Freebird]

Do you have a really good dealer that you trust 100%? I only ask because I've seen so many carbs that were WAY out after just being done by some dealers....too many dealers. I wish we lived closer so that I could check them for you.

[ColoNavy]

With the rise is gas prices I switched from mid and high grade to 87 octane. Not only did my mileage go up but the backfiring stopped!...two unintended outcomes!

[Bummer]

Any chance they followed Yamaha's carb sync instructions? Of course there's no way for you to know, but if they did it probably made them worse. This is one of many things I think it's best to do for oneself. Nobody loves your stuff as much as you do. There is no "good enough" under my shade tree.

 

FWIW, free carb syncs at Bummer's house. Might as well get some use out of that two foot long screwdriver. A little far to travel you say? Hey, it's a Venture. Got a valve adjustment tool too, but I'm not volunteering for that one.

[V7Goose]

It sure does seem odd for the popping to start right after they sync the carbs. If it was an exhaust leak at the Y, it should do it all the time (but infrequent). My bet is on a torn vacuum hose on the right side. They probably cut it while trying to jerk it off with pliers - they will get damaged REAL easy when pliers are used and they get cut on the edge of the nipple. It is also possible that the rubber cap on the other nipple is leaking. Even tho your bike is not that old, this can start quicker than you think. Easy test for that is to just swap the rubber caps from the left and right side. Since you said it was only popping on one side, if it changes, it is the cap. But the first thing I would do is pull off the right side vacuum hose and carefully look around the end while bending the hose, looking for any small cut.

Goose