Ok, I own a 02 Dyna Wide Glide. I have anafter market intake (filter)and Vance and Hines straight pipes. I Purchased the bike on 12/23/06 and it has been flawless since. Recently my bike is back firing more often then usual and "hissing" sometimes where is wants to stall when I pull on the throttle (not as often). What is happening?? A local shop says its normal for a carburated bikeand common... why has it not done this for two months but started now? A friend pulled out of my driveway last night on my bike and it back fired with a flame out the exhaust??? WTF??

Any help would be much appriciated.

 

I had the same problem on my 05. These twincams need back pressure. I put aset of baffles (modified ones)in my pipes and that helped the popping. I didn't want the baffles but you have to do what you have to do. On the plus side I got my power back on the bottom end, hope this helps. Dave...P.S. also there is an idle richener on the bottom of the carb that has to be adjusted and it is hidden by a plug (it has to be removed).

 

It is common, but not normal. It is most likely running too lean, which the factory sets them up to do so they pass EPA standards. Add a better breathing Air Filter and pipes and it is worsened. May need to Jet the carb, and as TC Dave says, adjust the air/fuel ratio.(the hidden screw).

 

Thanks guys...

 

Did you add the pipes and air filter or did the bike come with them when you bought it?
Your bike shouldn't backfire if setup properly.
As TC Dave said if you are running drag pipes adding baffles will help.
Go to the Do it Yourself section and read a few of the posts they are very helpful.
https://www.hdforums.com/m_149206/tm.htm

 

If it was running fine without backfiring and you've made no changes to pipes or intake and it just started hesitating and backfiring - I suspece an intake leak. You can test for leak by spraying a little wd40 near the intake manifold while it is running. If there is a leak you should notice an increase in RPM's when you spray the wd40.

Do your vance and hines pipes have baffles? If so, you shouldn't have a back pressure problem.

 

Yep, sounds like its lean. Adjusting your secret idle mixture screw should help. Also installing a set of power cones (AR valves) at the head end of your pipes work great for restoring back pressure when running straight pipes without baffles.

 

After cleaner and pipes mine started doing that coughing/sputtering/backfiring thing when the weather started cooling off. Went the route of re-jetting carb with a Yost power tube. Large power increase, runs like a champ and great throttle response.

 

Same setup I have on my 2001. Works great.