I have a 2009 IRON 883, no modifications. If the bike sits in the sun all day and the ambient temp. is 100+ (which is not uncommon in Houston) immediately upon start up I get a high pitched whine sound. Closest sound I can think of is a disc brake squeal. This sound is intermittent, does not vary in pitch or frequency with engine revs or bike speed but can be loud or softer and of different durations. OK and here's the REALLY STRANGE part...if the bikes stopped and it's making the noise and I put it over on it's side stand - the noise stops, bring it back up to verticle and it starts again. I'm not delusional - others have witnessed this.
Any other riders experience this - any ideas???

i don't kave a clue what that could be. i would take it to the dealer and have them put their fancy computer on that one.
sorry i am no help. just did not want you to think nobody was reading your post.

Sounds like it could be coming form your primary. Since the oil is hotter when the outside temp is up it may get thinner. In the primary you have a chain tensioner and on a sporty it is also the tranny oil. It could be a bearing that is not getting enough oil, or the oil is too thin when it gets hot out. When you rest it on its side stand it is getting enough oil to stop the squeal. My guess is that you may not have enough oil in the primary. I would change the oil use the Harley recommended oil for your primary and see if that helps. Making sure that you have the right amount in the bike. Your chain tensioner may need adjustment. Could be the clutch but I really can't tell from here. Need more info. How to check the oil in the primary. Stand the bike up straight and take the derby cover off and there should be 28 ounces, Anyway the oil should have contact with the chain. I usually just put the entire quart in when I change my oil. Be sure not to lose the "o" ring on the derby it is reusable. If you check the oil with the derby cover off make a mental note of the level. Drain the oil and put the recommended amount in and see the difference. That could tell you where you stand.

Hope this helps, let us know how you made out.

Lenny

A brilliant thought - I use HD-synthetic and it was just changed at the dealer for the 12,000Km service - maybe they skimped a little -
thanks all for the replies

noise goes away when leaned...
oil level is too low, the bike leans the primary into the oil and the noise stops. check oil levels and also oil might need a change out if it is that low.

Glad to help, hope you find out what the cause is. Update us on what you find out.

If this diagnosis is correct, then we are hearing 'metal to metal' or a binding drive unit, like misaligned pullies or sprockets. It could even be a simple matter of wear--all in all, it ain't right. Considering the number of engine revolutions such a condition makes unseen, I have to wonder about damage. There's nothing like being stranded at 3:00AM out in the sticks with a broken scooter.

When I was a kid there items like "motor honey." They didn't do anything really but quiet noise in already abused and worn out older engines. Harleys can be rebuilt, we still have flatheads in use. Are we sure that 'adding oil' and hoping for the best is sound advice? I'd like to check for damage.

I checked the oil level and it was a bit off the mark, not bad maybe a few oz's - topped it up and am doing the test today- as we speak the bike's sitting outside in the sun & we expect 103+ today. No noise on 25 mile RT commute to work yesterday but the bike was in the covered garage while at work.

IF this has been a long term problem Tourist's point of excess wear is a concern for me also. If it just started and only lasts a couple seconds kind of thing it might be just a case of low levels.
Let us know how you make out with your test.

I've heard that noise with my Sportster also when it tops 100+. Live in Az.. Couldn't figger out where it came from. Doesn't seem to cause any harm. Always thought it was some kind of pressure relief because of the extreme heat. Now you got me wondering.