Help With Miss/Backfire

[pa-powerstroke]

So I have only had the bike a few weeks and not been on it much at all. When I had taken it for rides when I really got on it, it felt like it would kind of studder at higher speed/rpm. Almost like it wasnt getting enough fuel maybe. I took it out a few days ago and today and noticed that it seemed like the right cylinder was missing at idle and low rpm. Riding it still had a the studder at lower speed and rpm than before, didnt really get into it much but now it is also backfiring when I would left off sometimes. The other thing I have been noticing is a tick coming from the top end of the motor, seems like valves to me. Is it normal to tick a little? I know these bikes dont have shims and I figured my valves just need adjusted. Anyone have any ideas? I was thinking to have it jetted at least. What else? I would love the help. 79 and it had drag pipes on it when I got it, I cut about 20 inches off and they end right about where the mid controls would be. Would this make a difference in jetting?

 

[5twins]

The first thing you need to do when you get one of these is give it a complete tune-up - cam chain adjust, valves, points, timing, then adjust the carbs. Have you done that? Probably not. Next, if it's been modded, like your pipes, you need to check the jetting to see if it's been adjusted accordingly. Have you done that? Probably not. Now you've altered the exhaust which could change the jetting requirements. It's running pretty much just as I'd expect it to, probably better in fact, lol.

 

[ANLAF]

Pa-powerstroke, get to know your bike. Don't rely on it working perfectly well, you should go through the procedure 5twins suggests. backfires and missfires are likely to be the carburettors (and 5twins has a wealth of knowledge) but also check your headers are located properly - exhaust fumes can re-ignite in certain condition (bring on the chemists to explain) - I've had some tremendous backfires when I didn't seat and tighten up one header properly.

Anlaf