Engine Noise?

[gnonne]

Some of the time when using about 1/3 throttle I get a rattling/tapping noise. Sounds like it could be the valves or something external - can't tell while I'm on it.

6500 miles on my 2007 S 500ie, if that helps. Never had anything done to it, except 1000km service, recalls, a few oil changes, and a battery.

Accelerates and idles just fine - the noise seems to be in the lower rpm range, but somewhat above idle - no tachometer on this model. Oil is full and fine - changing oil quieted it down last time it did this - if I remember correctly.

Temp is good and no real gas smell in oil. I've been using some 93 and some 87 gas, not really sure how that affects it, mostly Sam's Club lately. Gets 62-64 mpg, real uniformly and nothing is leaking.

Any ideas appreciated.

[Bob Walker]

Valves tapping would be hard to hear except at idle and probably only heard with the plastic removed.
I had some unexplained rattles on my 07 500ie. When I repainted and had the plastic off I added foam tape wherever anything could rattle. The hard plastic electrical plugs that are everywhere were big sources of rattles. This tape is sold under the name Armoflex at Home Depot. 1/8" thick and 2" wide. I also added some strips under the front cover where the brake hose was rattling against the front cover. I couldn't believe how quiet she was after adding the tape.
One other source for the rattle could be the Variator or the drive belt idler pulley.
One other rattle That I discovered recently was from one of the chrome plated plastic covers that cover the shocks and attach to the front fender. One of the tabs broke off and it sounded like something major was going to fall off. I repaired it with epoxy because the replacement was around $65.00.

[tomd]

Sure its not the rear fender rattling or some other buis.. mine rattles quite bad but its not engine its coachwerk etc make sure its not that but yes these engines are noisy by default

[gnonne]

I have found a few rattles on the front end and fixed them with foam weather striping, etc. But those were more of a buzzing. This a tapping or rattling. At times is sounds like it is coming from inside the exhaust.

The rear fender does "clap" a lot over potholes or rough roads and makes more racket than it did when new, but that's not it either.

I'll run it on the center stand and check around the bottom with a heat-resistant glove. Maybe its down under there somewhere.

[Bob Walker]

I have a suggestion. I have used this technique to find rattles in 4 wheel vehicles. Take a rubber hammer and bang on the tires. You can then move on to banging on different places on the frame. A rubber hammer can break platic parts and even bend light gauge metal parts so use caution. Giving the tire a hard lick will not hurt the bike and will send a shock wave through the frame. I would hit it hard and soft to see what frequency is necessary to create the rattle.
This technique probably not recreate a rattle that is caused by a faulty part of the running gear.

[gnonne]

I ran it on the center stand and got down on the floor to determine the source of the noise.

It really sounds like a small hammering inside the lower part of the engine. I can't imagine a crank bearing or wrist pin is bad at 6500 miles, but it sounds sort of like that. It is definitely NOT from the top of the engine.

I will drain the oil in the morning as see if perhaps the oil screen is broken, which might make pieces run around in the crankcase. But, I don't see this as very likely, since it is running so well overall.

Has anyone else had problems with the bottom end of these engines?

How difficult is it to get inside the crankcase and replace a bearing if necessary?

[Bob Walker]

Their is a way of determining if you have a bearing problem.. Their is a company called Blackstone Laboratories who specialize in determining the condition of an engine or gearbox by analyzing the oil. If you have a bearing going out their will be signs in the oil.

[Bob Walker]

I agree that it would be unlikely that this engine would have a major part fail at such low mileage. My next move would be to remove the variator and start the engine. Be careful that you don't over rev because the engine will have no load on it.
You could have some bad gas causing a pre-ignition knock.