K75 Engine noise

[bgcameron]

Thanks for that info. I am not sure that is the issue I am having though. The engine is completely smooth sounding throughout the rev range, but then right at 3500 rpm under certain light loads it sounds like a rock banging around in a tin can. It is so loud that it is startling. Unfortunately I wasn't really able to capture the sound well in my video.

[Laitch]

I am not sure that is the issue I am having though.

Then enjoy the hunt! Let us know what it is, how much it cost you to find out and the remedy. Maybe someday, despite everything, you'll ride the moto only to enjoy its g-forces and the scenery flowing past you.   That will be challenging. 

I wish you peace during this difficult time for you.

 

[daveson]

Would it be worth a bit more searching to try to pinpoint its location?

A few more desperate maybe's. If the noise is louder with the fuel cap opened, have a bit of a look, maybe a filter or hose tapping against the tank,  or pump.

You might have two different noises, one about idle and one at ~3,500rpm. If you pull the clutch in about half an inch (or as much as you can without letting it slip) check if the noise at revs then disappears.

Maybe with a screwdriver to help, check for a healthy click from the injectors, timing light in synch with plugs, headers. Gear box and stuff. Granted it's desperate, but easy checks

[Laitch]

More ride, less rumination. 

[bgcameron]

So I took it out again today. The noise was ever present at any gear and (almost) any speed, as long as there's a light load. Now here is where it gets confusing:

Going up a slight hill, when I heard the rattle I pulled in the clutch and held the RPM around 3500 with the throttle. The noise persisted until the bike slowed down to under 20km/h or so.

I figure this should either narrow it down or do the opposite!

[daveson]

You could also call it a tappet noise. Did you check the valve clearances when you had the valve cover off? You might have some excessive gap/s.

[bgcameron]

You could also call it a tappet noise. Did you check the valve clearances when you had the valve cover off? You might have some excessive gap/s.

The valve clearance is all within spec.

[Laitch]

Your latest description characterizes it as something other than an engine noise, bg. As long as it doesn't start telling you to strip in public or ride to Victoria wearing a loincloth and carrying spear to storm the Parliament Buildings, I think you're OK.

[daveson]

Rolling three threads and two forums into one, well done.

A bit of biffo never killed anyone
(excluding fatalities)

[bgcameron]

Your latest description characterizes it as something other than an engine noise, bg. As long as it doesn't start telling you to strip in public or ride to Victoria wearing a loincloth and carrying spear to storm the Parliament Buildings, I think you're OK.

Nobody would bat an eye in downtown Victoria!

I am confident now that it isn't the engine.. I am wondering if it is something to do with the clutch. Whatever it is, it is certainly loud. Cruising on the highway between 3500 and 4000 rpm it is just a consistent rattling sound.

[Laitch]

Record the noise under the new conditions you're describing. If you can't find a recording device that will accommodate a microphone with a long cord so you can affix the microphone on the frame, get a friend and have the friend drive next to you operating a boom microphone close to the frame near the intermediate housing while you perform your novel noise propagation technique with the moto. Nobody will bat an eye. Post the video.

[bgcameron]

Record the noise under the new conditions you're describing. If you can't find a recording device that will accommodate a microphone with a long cord so you can affix the microphone on the frame, get a friend and have the friend drive next to you operating a boom microphone close to the frame near the intermediate housing while you perform your novel noise propagation technique with the moto. Nobody will bat an eye. Post the video.

Here is a better video clip of the noise. Don't ask me how I did it haha. The sound is clearly heard at about the 24 second mark.

[daveson]

How did you do it?

Where was the microphone?

Did you try with the clutch pulled in a small amount (putting pressure on the clutch basket) to see if it eliminates the sound, or changes it?

Good work on this recording.

[Laitch]

Here is a better video clip of the noise. Don't ask me how I did it haha.

Instead of being coy, explain how you did it so somebody else who has a similar noise sensitivity can risk life and limb to record it for the benefit of others who want to identify it.

I have some questions.
Did you remove the timing chain guide rail and inspect within it for wear?
Did you remove the slide rail and inspect within it for wear?
Did you remove remove both the chain tensioner and tensioner strap to inspect them for grooves and other signs of wear?
Did you remove the tensioner plunger (pedestal) housing and the plunger itself to examine the condition of the assembly?

[bgcameron]

I taped my phone to the intake pipe on the right side of the air box.

Clutch pulled in, noise continues. Laitch, when the cover was off i checked all those components as you mentioned. Everything looked fine.

[Laitch]

How many Kms on the moto?

[Laitch]

i checked all those components as you mentioned. Everything looked fine.

Does that mean you removed all those components and inspected them? While you're thinking of things to keep from enjoying the ride, check all the exhaust manifold bolts for tightness when the engine is cold.

[bgcameron]

Does that mean you removed all those components and inspected them? While you're thinking of things to keep from enjoying the ride, check all the exhaust manifold bolts for tightness when the engine is cold.

I removed everything. The bike has 53,000 kilometers on it. It is a local bike and I am the third owner.

[Laitch]

That's early for a timing chain to stretch or wear. Since you've apparently confirmed the proper function of the rest of the parts in there, the hunt will continue. Don't forget your earplugs. 

[daveson]

Do you have this regardless of the engine being warm or cold?

I'd almost punt it could be a worn annular spring between the driven gear and idle gea, or shim. Is there a thread with this problem that has sound? In this case I'd just wear earplugs, mind you I wear earplugs without this sound.

Could you post photos of the bike and instrument cluster? Any signs the mileage isn't genuine?

[bgcameron]

Do you have this regardless of the engine being warm or cold?

I'd almost punt it could be a worn annular spring between the driven gear and idle gea, or shim. Is there a thread with this problem that has sound? In this case I'd just wear earplugs, mind you I wear earplugs without this sound.

Could you post photos of the bike and instrument cluster? Any signs the mileage isn't genuine?

It seems to happen regardless of temperature. I have no doubt that the mileage is genuine.

[daveson]

Why are you confident it's genuine? There's a fair few threads with the plastic cogs broken, they're like thirty years old, most of mine were wonky.

Anyway I'm curious, in Canada are bricks European (i.e. rest of world?) spec. or US? In the US bricks have miles on cluster and no light switch on the right handlebar. In Australia bricks have kilometers and a light switch. Does yours?

[bgcameron]

Why are you confident it's genuine? There's a fair few threads with the plastic cogs broken, they're like thirty years old, most of mine were wonky.

Anyway I'm curious, in Canada are bricks European (i.e. rest of world?) spec. or US? In the US bricks have miles on cluster and no light switch on the right handlebar. In Australia bricks have kilometers and a light switch. Does yours?

Local bike. The original owner didn't ride it much and the bike sat in storage for at least a few years. The 2nd owner didn't own it for long. The odometer reading between the first and second sale ads only changed slightly.

I believe this it is essentially the same as a US spec bike, but with a km/h cluster.

[daveson]

So no light switch but km cluster? Dunno if that's normal for Canadica. How's about photos.

What maintenance history do you know of?

[The Mighty Gryphon]

53,000km and spent at least a couple years sitting in a shed before it was sold to a guy who didn't ride it?

53,000km/30,000mi is barely broken in.  Sitting around unused sticks the pintles in the injectors and the rings in the pistons.  I'm surprised it runs.  All that engine needs is a couple thousand miles of 4000+rpm yeehaw to loosen things up.  Buy some friggin' earplugs and ride the damn thing.  You've checked everything and can't find any problems so go and ride it.