Any creative ideas as to what this might be?

 

 

Rust on the flywheel... check my previous thread. 

Hrm. I pulled the flywheel cover off yesterday. There's a bit (as in, a few small spots) of surface rust, but there's no evidence of any real water ingress or substantial rust.

By the way @miner, what was the fix? Just pull the flywheel and clean it up?

From the reed valve .

That occurred to me. It sounded vaguely like an air leak, which was weird. You think it's the reeds themselves, or something else related to the reed block?

14 minutes ago, reggie said:

From the reed valve .

 

Pulled the reed block. Everything was tight and the reeds are fine. Some evidence of leakage around the gaskets but nothing crazy and no change after reassembly. 

Reeds acting like reeds!

I guess it could be, but they didn't do it up until recently.

Hi, sounds like my gasser trying to start, only it takes more kicks most of the time. Ha ha.

Compression leaking out, or air squealing in or out from main bearing oil seals possibly. Have you only just noticed this sound?Compression leaking past piston rings as piston movement just stops....could be totally normal. In the quiet, ghetto blaster off, Chris Evans muted (gone would be better) talkative by standers asked to multiply 3.789 X 754.89 in there heads, and no calls from the kitchen about things not working...and you will hear all sorts of noises emitted by your faithful steed. If it were my machine and it worked as good as before the noise noticed then ignore and ride on???Your engine running will utilise the compression increase on igniting the fuel and air and this will force the piston towards the cylinder walls increasing the seal. That’s why when the rings are nipped or gummed up power loss is felt. The only other thing that comes to mind is the water pump seal may be squeaking, I’ve had no end of water pumps that make all sorts of noises straight out of the box. The lube contained in the anti freeze usually helps resolve that issue. Do you still run anti freeze in your bike? Any work done and you may have had tap water put in the cooling system. I always recommend using distilled water pre mixed with the best quality anti freeze you can obtain, less chemicals to attack the aluminium. Hope you can either eliminate this sound by finding the cause or satisfying yourself that it’s nothing wrong.??

Take your plug out, try it again and then you can eliminate to a certain degree whether its compression related or friction related

Edited July 20, 20188 yr by faussy

8 minutes ago, faussy said:

Take your plug out, try it again and then you can eliminate to a certain degree whether its compression related or friction related

Good idea, I'll do that...

So warmed the bike up a few minutes (it doesn't make the sound when completely cold), pulled the plug, and the noise is still there. I'm mystified, mainly because it's impossible to pinpoint where the noise is coming from. I've heard from one person that says that have the same noise, and has continued to ride it with no sign of mechanical issues, so I'm inclined to do the same for the time being. I'll see about getting a mechanics stethoscope to help locate the sound.

On 19/07/2018 at 10:49 PM, heffergm said:

By the way @miner, what was the fix? Just pull the flywheel and clean it up?

Yes..... dremmel and some 400 grit paper to finish..... I tried oil in the bottom end, oil in the plug hole, still made it, was taking the casings off to start digging in and saw it.  It was corroded and it was the flywheel squeaking on the coil, had been getting in the pulser coil opening, bottom part of the casing gasket had a bit out of it.... googled it and it appeared to be a thing.