Topic: Whistle at speed and engine temp

[Scout]

I've got two other problems with my bike, here's the first one...

At speed (best heard around 60MPH), in higher gears, I hear a whistle/hum sort of sound. It only happens at around 1/4 throttle. If I close it, or get on it, it completely dissapears.

The other issue might be related. I've always assumed that my bike runs a little rich, because the plugs get a medium to dark-brown. However, I've read from somebody on the forum here that the oil filter case should be safe to touch no matter what the conditions. Well, after a 10 mile ride (the last two in heavy traffic), I pulled into the garage, and the oil filter case was definately hot. I could touch it, but definately not keep my hand on it. Since I don't get to ride that much on longer, high-speed rides, am I safe to assume that the bike probably runs a little ritch at small throtle openings, but at higher ones, it starts to run lean, and hence the high temp?

I guess I still can't get used to not having a temp gauge, like I had on all my prior bikes, but they were all liquid-cooled...

Scout

[Bob Wessner]

On the first issue, I'm a little confused by your reference to 1/4 throttle and 60 mph, seems pretty fast for 1/4 throttle??

As for the temp of the oil filter housing, I remember checking the temp of the oil in my tank last summer right after a long run, it was 180 degrees. If it is that hot in the tank it would be that hot, if not hotter in the filter housing. I doubt anyone could leave their hand in contact with that kind of temperature.

[cadler]

I think 125-135F is touchable.

[Scout]

Well, maybe not 1/4, but crusing. Just keeping a constant speed, so maybe it's more like 2/3 throtle.

Scout

[Bob Wessner]

The whistling noise is a stumper? I think you are probably OK temp-wise, but if you are concerned, you could pick-up one of those meat thermometers and stick it in the oil tank immediately after a long, hard ride to give you some sense for the temp. Probably slightly lower in the tank than the engine. I figured if it was accurate enough to determine when a pork roast is done, it ought to suffice for a bike engine. 

[Scout]

Yeah, I might have to get me one of them meat thermometers

The whistle is very odd. When I first hear it, I thought it was just a tire hum or something like that, and didn't pay attention to it. But now that I've actually tested it and realized that it depends on throttle position only, I'm quite perplexed myself....

Scout

[dusterdude]

could it be a vacuum leak singing?

[mlinder]

Probably just the noise of the carbs sucking in air.

[dusterdude]

did you say sucking,yes it definitly sucks.vduuuub.my attempt at being humurous.

[comcrx]

the carb on my truck whistles at about 1/3 throttle. its just resonance from the air flowing through certain passages in the throat
my mud tires, however, start to hum at around thrity MPH.

I guess what I'm saying is, if it truly sounds like a whistle, its just air flowing over/through something to make it resonate like that and nothing to worry about

[Scout]

I really tried to listen to the sound, and I guess it sounds more like a high-pitched tire hum than a whisle. It's not too loud, so I guess I'll just forget about it for now. I did have to make a mess of the bottom of the airbox in order to get it apart (damn bolts were moving inside, so I had to cut out the plastic to get a grp at them,) so I will try covering the screw holes with some heavy duty tape to see if that makes a difference too...

Scout

[clarkjh]

High-pitched tire hum?  Never heard one, but if it sounds like it's coming from the tire could it be a dry bearing?  Just a thought.

James