Rattling valves...

[RamMedic]

We all know what a car sounds like with rattling valves, climbing a hill, bad gas, sounds like a diesel. What is the root cause of rattling valves? As some of you know, since I have done my cam swap I have had a ticking noise in my FLHT that only seems to occur while the engine is under a load. Let off the throttle and it goes away, half throttle noise is back, full throttle tick goes away. Are twin cams prone to rattling valves? Before you ask, I have added octane booster and the noise seems to subside somewhat but not completely. Any comments????

[CoolMaker]

Good ole "Spark Knock"...... :wink:

[wrecker]

if it is efi sounds like you need to fine tune the map other wise adjust your timing

[Fubar]

does it sound like ball bearings rolling around in your engine?? or is it just a slight tick or ping....my ticks under load, but it's nothing more then normal valve train noise.....I've been on a bike that had spark knock and it is a very big difference in sound. I don't have the experience to tell the difference in all the potential problems, but an experienced wrench and a stethoscope are a great pair.
If it is spark knock, then about the only thing you can do is play with the timing...twinkie's are more apted to spark knock

[Kagan]

I have the same noises occasionally. It's no big deal. Do you run a tach? I have one and the problem is lugging. If I demand torque quickly at anything less than 2400 RPM it doesn't like it. I try to keep my cruise RPM's around 2800/3200. Anything less and it will sound noisy.

[RamMedic]

My bike is a carb bike. So the only way to change the timing is to purchase an aftermarket ignition (correct?). I added a different brand of octane boost today and the rattle subsided quite a bit. I have been thinking it was a rattling lifter this whole time but now I am thinking otherwise. Fubar, I have no idea how to describe the noise to ya. It just comes and goes. It is loud enough at times that I can hear it over my stereo and pipes even at interstate speeds. Very annoying. I guess it may be time to change my ignition. I really want to get this straightened out before our Canada trip in June.

[Fubar]

Here is some points from Mr Peterson...it really give's you the back ground information you need. I would also check aroun d his site, unless you are positive that you have a spark knock.....

CHeers,

http://www.heavydutycycles.com/camign.htm

[Fubar]

Just to add something here Ram...I'm sure you heard the old saying...."Chasing noises in a Harley will drive you nuts" LOL

Just an FYI, I'm sure you all ready know this but sitting on top of a mechanical engine, you will hear noises....and whenever you add preformance parts, like you highleft cams, the noises can increase. This is normal, it isn't something that always happens but it is normal.

I'm just not so sure you have any problem at all....I really would ahve a tech listen to it, knowing you had recently upgraded the Cams.

[wrecker]

Originally Posted by Fubar

Just to add something here Ram...I'm sure you heard the old saying...."Chasing noises in a Harley will drive you nuts" LOL

Just an FYI, I'm sure you all ready know this but sitting on top of a mechanical engine, you will hear noises....and whenever you add preformance parts, like you highleft cams, the noises can increase. This is normal, it isn't something that always happens but it is normal.

I'm just not so sure you have any problem at all....I really would ahve a tech listen to it, knowing you had recently upgraded the Cams.

i agree here with fubar , besides it is not a freaking honda

[Fubar]

Thank God for that LOL