Between 2000 & 2500 rpms in 5th and 6th gear of my 2007 Ultra Classic I get what sounds like a valve rattle. 1 shop told me it's a Harley thing and nothing can be done. They also said won't cause a problem just use and oil additive to help quite it down. The bike runs great other then that. Can anything be done or should I just add the additive?
Make: Harley Davidson
Model: Ultra Classic
Engine: 96 ci
just making sure that the oil level is OK. a little apprehensive on adding a oil additive was going to on next oil change
Welcome. Thank you for choosing Just Answer.are you referring to a spark knock?Steve
I believe that's what it might be. Spark plugs are new. I even had them check my Primary to see if that could be causing the noise that was fine.Is this an octane thing I try to get 93 and above but difficult in some areas I travel
I think it could be spark plugs are new
spark knock IS a Harley thing.
HD has tuned your engine extremely lean and with maximum timing advance.
I completely disagree with your shop opinion that it is ok. Spark knock, otherwise known as detonation or pre-ignition will destroy your engine.
this is what it does to pistons:
this is what it does to valves:
octane boost will ease the symptoms, but that is not the cure.
a well tuned Electra Glide gets 35-45 mpg. my guess is, you are doing a little better than that.
A HD stage 1 download will help. it richens the fuel mixture, tweaks the timing and raises your rev limit to 6200. the dealership can tell you if it is installed or not by hooking their laptop up to the bike.
if that doesn't eliminate the spark knock, you will have to add a tuner. HD has a few download tuners which make your ECM adjustable. Power Commander is a add on tuner from Dyno Jet that also allows you to richen up the fuel map and tweak the timing map.
with the power commander, you can retard the timing 4 degrees over the entire timing map and add a percent or two to the entire fuel map, in steps, until you have eliminated the spark knock.
I hope that answers your question and if not, please ask for more detail or any clarification you might need.
30+YRs,MMI,HD tech,HD early,engine rebuild/perf,bike builder,kit bike program manager, cci 2001-2004