9

Harleys are notorious for valve noise or clicking from exhaust, so when my 2011 Ultra with 110 Screamin' Eagle started clattering a bit more than usual I didn't worry too much, but then a few miles later it reacted very loudly when I tried to accelerate hard so I gently coasted for a while.

After stopping, it then wouldn't start. Symptoms include backfiring, loads of smoke from the right exhaust, and some from behind the air intake when pressing the starter, and immediate stall when the starter is released.

The recovery guy made a guess that it could be a failed spark plug (which I hope is all it is) but he didn't have any tools to check (Imperial sizes in a metric country :-( ) so that was a guess.

Any thoughts?

Rory Alsop
  • 18,600
  • 7
  • 60
  • 100

2 Answers2

16

With a no-run scenario, think FASTEC:

  • Fuel
  • Air
  • Spark
  • Timing
  • Exhaust
  • Compression

As there's smoke on one side only, I'd be focusing on testing for spark, timing and compression.

If I had to hazard a guess, the smoke near the intake tells me that the intake valve is not seating properly.

Zaid
  • 39,276
  • 50
  • 151
  • 294
11

FASTEC is exactly the right process to analyse this, as @Zaid said. It turns out it was contaminated fuel! That doesn't really explain why smoke just from the aft cylinder, and why there was smoke coming out from near the air intake... My guess is the misfire was powerful enough or off-time enough to get through an intake valve.

The downside: required full flush and clean out The upside: no damage, so even though I need to pay for labour costs, it's not too bad.

Our assumption: the area we were in that weekend had suffered extreme rainfall and flooding so perhaps runoff had washed contamination into the garage's fuel storage.

Rory Alsop
  • 18,600
  • 7
  • 60
  • 100