I have a rattle that I can't track down. It sounds like it's coming from near the gearbox but it's anywhere from the gearbox to the rear axle. The sound was there a bit last year but had gone after the bike had its main seal replaced at the shop and had been put back together. It has slowly come back and is getting worse. It seems to disappear under load/acceleration. The sound is there with the engine off and in neutral! Mudguard was loose but is now tight. Pulled out all the underseat tools. No joy. 

I CAN'T FIND THE CAUSE AND IT'S DRIVING ME MENTAL! 

I'm away from home for three months. No tools. No support. 


'89 K100LT

Does it disappear when you pull the clutch in?
I can always lend you a hand if you're near me.

Exhaust heat shield fastener?

.

Bit confused with your comment that the "sound is there with the engine off" - my bike goes very quiet with the engine off as I would expect it to!

If it is the heat shield on the exhaust, it is easily fixed with just an allen key from the tool kit.....provided you can get the remaining old fasteners out (I was lucky - mine came out with minimal effort) and you only need to remove the left hand pannier to get full access.

I just replaced mine last weekend, having developed a rattle/buzz from the back end (especially at certain resonant frequencies). The front of mine is secured on a flexible mount and nylon nut (10mm spanner) and there are 5 allen bolts that hold the heat shield onto the muffler (3 on the side and 2 on top). On inspection, I found that my heat shield had lost 2 of the allen bolts (and the captive nut that they screw into) and one was very loose - which explains why the buzzing/rattling was getting worse and more annoying.

Ordered replacements from James Sherlock last Friday lunchtime and postman had them in my sticky mitts first thing on Saturday morning....but I am a bit closer than Aus. They weren't cheap at £1.56 each - stainless steel, but should last better than the originals. 310805 for the nut, 310806 for the allen screw. I used a dab of exhaust repair paste to help hold the captive nut in place. Fitted in about 15 minutes and made a massive difference in noise, as well as ensuring the the heat shield won't fall off completely (or worse). The James Sherlock site seems to suggest that the K100 has 6 of the allen screws/nuts, maybe mine was modded with the flexible mount at the front at some stage by a PO which is why I only had 5?

No welding required...unless any heat shield nut holders have broken off the muffler.

http://www.james-sherlock.co.uk/component/virtuemart/?page=shop.browse&category_id=333

As per previous posts, I have no link to James Sherlock, just a repeat customer who is pleased with their service.

Oh my goodness no, it's not the heat shield. It's a 'rattle' not a massive high frequency vibration. It sounds like a pebble bouncing around in a plastic bucket and it sounds like the gearbox area. Engaging the clutch, hot or cold running makes no difference. Maybe the clutch pushrod rattling against the exhaust - no. Side stand clutch cutout arm- no. What is killing me is that you can hear it with engine off and in neutral which means it has to be the frame or swing arm or something but I can't find it. The only time it seems to disappear is under acceleration. And because no one else has mentioned something like this means that it's probably something pretty dumb and I'm going to be embarrassed but I don't care anymore.

What is confusing with your description of the symptoms is that you mention the sound is present even with the engine off and in neutral.  For most of us, that means the bike is stationary and not in motion.  So, if the noise is not related to the engine nor to road speed, how can a noise be produced at all?

Is what you mean "when the bike coasts in neutral and with the engine turned off, I still hear a sound"?

Sorry. Rolling the bike down a hill. The vibrations of the road surface will cause the rattle.



HOLD IT! STOP  PRESS! FOUND THE SOURCE OF THE RATTLE (happy, happy joy joy).

I have a RAM shock. It's the damping internals of the shock. Adjust to maximum = no rattle. Adjust to minimum = rattle. Thank F for that. Although, I'm not sure what the implications are for the longevity of the shocker but at least it 'aint the gearbox/something expensive/something that will kill me.

Sorry to waste everyone's time and sorry i wasn't very clear on how I phrased the problem.

Thanks.

D.

merldave wrote:
Sorry to waste everyone's time and sorry i wasn't very clear on how I phrased the problem.

The forum is here to help people and if all things were the same, then life would be pretty boring.

I will be buying a RAM shockie in the future, so you have helped me by making me aware of a potential issue.  So thanks from me. 

D