I have been messing with all kinds of stuff to get the topend of my bike working correctly. i have an 02 sportster that i just did a stock conversion to a 1200. it ran strong early on but as i rode it a little harder i noticed that i was getting a tinging sound on and off in the rockerbox in the front cylinder. it has something to do with the valves for sure but sounds like the exhaust valve. when it is cold it is normal but after it warms a little it starts the ticking and then the ocasional ting just above idle. I also noticed that it back fires more than it use to when off throttle decellerating. I also noticed that at a steady speed it surges alot. at full excelleration it doesnt hesitate at all but doesnt seem as powerful as before. Im worried i may have a broken spring or bad valve or bad lifter. has anyone experienced this. I am going to do a compression check but i am sure it will be fine cause it idles fine but runs a little rough above idle. also i took off rocker boxes and none of the valve terraine is hitting anywhere and no shards up there either. and if it is a spring, will my old 883 springs work in the 1200 head?
Location: The Center of the Sportster Performance Universe
Sportster/Buell Model: XL883
Sportster/Buell Year: 2007
Sportster/Buell Model #2: Buell Cyclone
Sportster/Buell Year #2: 1999
883 and 1200 heads of the same year use the exact same spring pack. Literally the same part number. But if you put rubber mount heads on the bike then no, those springs are different from your stock '02 sprigs and they are not compatible. What year of heads did you use?
front cylinder only? sounds like just the exhaust valve too. Im thinking with the poor cruse speed and tinking sound only after hard excelleration. maybe a bad lifter or clogged lifter not releasing the oil out of it? could tinking be the valve being forced shut on compression till the lifter releases the oil?
Your bike has roller lifters so a flat cam would be very rare. It sure sounds like detonation to me. I would do a leak down test to make sure you do not have a head gasket leaking as that is what it sounds like.
I am going to do a compression test tonite and a headgasket leak should show up. if not i wonder if the metal cometic head and base gaskets increased the height too much and the lifters have 40k miles on them and may be too much to compensate for the additional gap. I also put sealant around the pushrod tubes so i wonder if some could have gotten in there and messed things up. its the tinging sound that is throwing me. i would think i would still only get a ticking sound. I tightened the head acording to the specs i found online at 42lbs and in sequence. early on i had the back gasket leaking but i re torqued it and it cleared up a swishing noise i had when i first assembled the heads.
All i can think of right now is as Dan said you're probably detonating.
The sound is a ping right?
Can you explain exactly when you hear this noise?
Did you rejet the carb after conversion? You may be running to lean for a 1200.
Have you taken a look at your plugs to see what color they are? this will help in finding out if your lean or not.
A tapping sound is completeley different than a "Ping"