Did the Lake Superior Circle last week and my engine has developed a bad knock (hit to hammers together) when you start to roll the throttle on and load up the engine. Stopped in ******* MI. they opened up the primary and tighend the primary bolt. It didn't help. Stopped at second dealer in Canada and they said it may be a cam problem(chain, bearing, ???) but didn't have the time to look at it. Any ideas I am going to take it our dealer here and get the THAT's normal bullsh*t.

 

Spark knock. Bad gas will cause it...and there certainly seems to be a rash of it, recently. A colder plug might help, but the real fix is retarding the timing a few degrees at that spot.

 

I have a 2007 Fat Boy 96 cu. in. with Fuel injection. It started knocking at 880 miles Took it to the shop, they changed out the ECM and said it was ready. Same knock. They have had the bike for over a month now and can't figure out what is wrong. They are talking to HD techs. and are talking about changing cams. I think they are just changing parts. They don't actually know what is causing it. One time the timing will be 60*, and another time it will be 120*. It is all over the place.

 

I don't think it is spark knock, it is metal on metal

 

Spark knock sounds like metal on metal.

 

Is spark knock rpm specific it only happens between 2800-3000 and only under load (up a hill)

 

I've got an '07 Roadglide and live in Tucson, AZ. I bought the bike at the end of March and for the first few rides didn't notice anything. Then riding out of Tucson one day, the air temp had risen to 80 degrees or so, I heard what to me is spark knock. It only happens when the engine is loaded (climbing a hill or rolling on the throttle). When I took it to the dealer and told them, their reply is that "it's happening on all 96's to some degree or other. Now, I used to have a shovel that was stroked and couldn't get rid of the spark knock. The 96's run a bit hotter since to get to 96 ci, Harley decided to lengthen the stroke vs increasing the bore. Stroking increases the compression. Increasing the compression makes the compressed mixture hotter before the spark. If there is any carbon buildup at all in the cylinder, that carbon will ignite the fuel air mixture prematurely, causing the spark knock. Now this is all my opinion...but it makes a pot full of sense to me. Since the 96's run hotter than the 88's, I think what I'm going to do (besides running synthetic oil...which I've been told by more than a few people will run up to 20 degrees cooler), I plan on installing an oil cooler. I'm hoping this will cool the cyclinder temp enought to stop the knock. The service writer at the local Harley shop says that Harley is aware of the problem and is working on a fix. Don't know how true that is or how to verify that.

 

Yes. That's detonation to a tee.

 

i have a 93 80" evo that i just rebuilt with new cams, lifters, valves, pistons and the whole nine..i put about 2000 miles on it and i have got the same problem. even adjusted the primary chain, and the noise is still there.