Hi all. I just recently purchased a 2000 Sportster 883. It had been sitting for about 10 years, but after taking apart the carb and cleaning it a couple times, (okay more like 6 times), and changing the accelerator diaphragm, I finally got it to run. The only problem is that I get this really weird sound in 4th gear and a little into 5th. I can only describe it as a kind of loud echoing clang sound that increases in pitch a little bit as the throttle is increased. It seems to happen right when combustion occurs, as it goes along with the engine. I searched through the forum for a few things to check, and will check to make sure all the bolts on the bike are tight. Maybe a loose bolt on the exhaust shielding. My greatest fear though, is that the timing is off and causing this sound, and I have now forever damaged the engine. Does any one have any ideas as to what this could be?

 

Just check the entire exhaust. Heat, shields, mounting bracket bolts, and the flange nuts. If the exhaust has baffles make sure to check those also. Not knowing what type of heat shields you have, if they use hose clamps then you should check the loops on the inside of the shields. I have seen those break. If those break then tightening the clamps will not help.

 

Welcome to the forum, and welcome to the H-D world of frustrations and satisfaction.

Probably something really weird.

I once spent weeks trying to chase down a loud clanking noise that I swore was going to cause the engine to seize up on me. Turned out one of the tank mounting bushings was shot, and the tank would rattle metal-on-metal at certain rpms (vibrations). I racked my brain trying to figure it out. But if it is an "echoing clang" like you say, I'd start at the tank area. Or even the oil tank area as well.

Another time I had a bad knocking sound from time to time. Never could make it do it, but it would occur every now and then. I swore it was in my primary drive and was going to grenade soon. I started hunting by going through the primary, pulling the transmission, etc... I wish I had started on the other side of the bike. It turned out that the spline teeth on my main drive pulley were badly worn, and the pulley would occasionally slap on the transmission shaft and make a horrendous knocking noise. Thankfully the spline on the shaft was not damaged.

Go over everything and check for loose bolts, worn rubber, etc.... I'm betting the vibrations at that particular point in your riding are causing something to rattle around. Sometimes they sound like they are coming from point "A" when in fact they are coming from somewhere on the other side of the bike.

Good luck, let us know what happens.

 

You have pre-detonation, or 'pinging' What gas are you running? Try a tank full of 91 octane,if you can find some in your area.

 

@ hdbob Yea I've been running it with 91 octane. Maybe ethanol is the issue? I've been making sure that the pump I'm using doesn't have any ethanol stickers but maybe they aren't required to provide that information.
@ TStephen I'm about to go outside and check all the bolts, just gotta let it warm up a little bit. It really does sound like the gas tank is vibrating or resonating. I'll make sure there's the little rubber protectors on it, because I swore I saw one on the ground the other day haha. Also there was a securing bolt missing from the back of the gas tank when I purchased the bike...

 

I don't think it's a pre-detonation issue, that would show up in more than just the gear/rpm range you described I think. But if you're concerned about that, check your timing. Not a big deal.
I run 93 ethanol in mine because usually the pure gas around here is 89 octane at best.

BTW, what Lancaster are you from? PA, SC.....?

 

Same here, but no bushings, just a loose tank bolt. Made one hell of a racket, thought the top end was going to explode.

John