Lower-end noise from my GS850 daily driver

[Guest]

OK spooky new territory for me - furthest I've ventured in this territory was replacing a weeping oil seal behind the ignition years ago.

I commute every day, so I usually wear earplugs - might be the reason a friend was the first to notice the sound. I said "no, it always sounds that way." until I rode to a lunch appointment without the ear protection later that day. Hmmm, that must be what he heard...

So there's two things:
1.) a kind of whirring or fluttering type noise
2.) a tapping or knocking

I heard #1 the most and my friend heard #2. But there's also some vibration that I think is new, and I noticed it as an extra buzz in my knees and hands while riding. I'm guessing this is just the tapping making itself felt as well as heard.

Because of the ear plugs, I can't say for sure when the noise started, but it'd have to be within the last week or so, since the vibration in my hands and knees is also recent.

I'd checked the valve clearances recently, so the first thing I did was pull the cam cover off and make sure I hadn't made a bonehead move and there wasn't anything knocking around or grinding up there. Everything looks normal and turns smoothly - shims seated, valves springing, no unusual cam wear or timing chain movement.

Then did some searches about clutches and starter clutches before heading to Harbor Freight to buy a mechanic's stethoscope for a couple of bucks. Well, I don't know what I'm doing with one of those things, but it made it painfully clear that there was both a whir and a tap.

I took a quick video, but forgot to rev the engine, what you get at idle is mostly the tap. I can do another one if the whir is interesting, as that's more audible at higher revs. Sorry about the night-time video and the deplorable lack of cleanliness of my engine - seems like the oil seep has gotten worse than usual lately. Here's the vid link - https://www.youtube.com/watch?v=XhFXdGUx5GY

I don't know if there are ways to narrow this down (like more skilled use of the stethoscope), but I'm thinking of pulling the stator cover first to check the starter clutch and then pulling the clutch cover to peer in there.

So, any tips on what to look for or would you start someplace else? Does anything I've described sound like something else entirely?

[azr]

ooohhhhhhh......that can't be good. Does pulling the clutch make any difference? (doubt it does but might as well start with the easy things first). I've never had a bearing go before, I'm sure someone with more knowledge will chime in soon.

[Roostabunny]

Thanks AZR! No, don't notice any difference if the clutch is in or out.

[Steve]

Have you checked your carb sync?

Sounds a bit worse than any I have heard before, but a bad carb sync will have a knocking sound.

.

[blowerbike]

check the starter clutch 1st then if it's ok go to the clutch side and disassemble and inspect.
these bikes have helical gears also that can work loose from the backing plate.
last thing is i had an 1150 eat a main bearing before...sounded really similar to yours.
the video/audio may be making the sound worse than what it is...dun't know.

[Roostabunny]

check the starter clutch 1st then if it's ok go to the clutch side and disassemble and inspect.
these bikes have helical gears also that can work loose from the backing plate.
last thing is i had an 1150 eat a main bearing before...sounded really similar to yours.
the video/audio may be making the sound worse than what it is...dun't know.

Cool, thanks!

A main bearing? Sheesh, that's something. Those thing are the size of marbles. Hope that's not it, but we'll take a look at the easier stuff first.

[Roostabunny]

Have you checked your carb sync?

Sounds a bit worse than any I have heard before, but a bad carb sync will have a knocking sound.

.

Carb sync was on the list, since I had a wonky airbox boot for who knows how long (possibly a few months) until last week.

Dare to dream that's the knock, but I'll check the clutchy things first. Hopefully eliminate the bearing possibility.

[Roostabunny]

Well, doesn't look to my untrained eye like there's anything wrong with the starter clutch. I was hopeful, since getting back on the road would be relatively simple.

BACK IN TIME A BIT: I also vaguely remember a single sharp ping or whack sound one time in the last couple of weeks when I started her up. Reminded me of the sound the valves make when they slip off the tool and splatter oil in my eye. Anyway, she started right up, but for all I know that was when the noise started, since I was on my way to work (wearing ear plugs already). Really not sure, so take that with a grain of salt, but if you think it's important, let me know.

Leaned her over and slid a section of 3x3 landscape timber under the side stand foot extension thingie. Under the cover everything seemed in order. Gears meshed, all teeth where they belonged, no signs of destruction/shavings. The starter clutch (which I assume is the big gear behind the flywheel/magnet) rotated with some resistance (it was engaging/turning the step gear and starter gear) in the clockwise direction and didn't want to turn counter-clockwise. I don't know if one-way rotation is normal. EDIT - I do now, see below.

I tried to shine a light under the flywheel into the case to see if there were any signs of damage (like metal bits on the bottom of the case), but didn't see anything.

Here's what I saw under the stator cover:







Here's a link to the whole album if you want to see the other pics:

https://plus.google.com/u/0/photos/105656572281780568085/albums/5926975888482584305

It'll be a couple of days before I have time to look at the clutch, and need to read up on that area anyway. Just glad I was planning to do an oil change anyway.

Oh, and thanks again for any input, really appreciate it!


EDIT: OK, I've learned from re-reading this thread that clockwise-only rotation is normal, so "nothing to see here." And I also realized that, even though I was sure to use Loctite, I should have checked the stator screws just to be sure they were where they belong. Oh well, I'll pull the stator cover again before I crack open the clutch cover. Anything else I forgot to check?

EDIT 2: Should I start the bike leaned over with that cover off? What am I listening for? And how long can I run it before oil starts pouring out or something.

[Roostabunny]

Just a quick check-in - I'm going to get into the clutch in the morning, but before I drain the oil should I try running the bike with the stator cover removed?

I ask because I thought I read that in a thread somewhere, but the step gear between the starter clutch and the starter makes me nervous. It's on that thick hollow rod that fits into holes on the engine case and the stator cover. Seems loose enough with the stator cover off to be a sure-fire way to break an apparently sound starter clutch along with who knows what else (like my head or the neighbor's window) when that gear pops out of place.

I'm probably remembering wrong and common sense is prevailing, but I wanted to ask.

[bwringer]

Do NOT run the bike at all with the stator cover removed. Among other things, the stator cover supports the intermediate gear shaft.

I can't imagine why you'd want to do this.

[Roostabunny]

Do NOT run the bike at all with the stator cover removed. Among other things, the stator cover supports the intermediate gear shaft.

I can't imagine why you'd want to do this.

Something about checking if it got rid of the noise - but obviously I remembered wrong what was removed (something other than the cover, I wager). It didn't seem right to me, but I couldn't find the thread again to see what it had really said.

Appreciate it, Brian!

I will take that cover off again and double check that the loctite did what it was supposed to do and all stator screws are accounted for, and then go around and see what I find when I look at the clutch.

[Big T]

You didn't check everything on the starter side

Grab the starter clutch (the part between the big gear and the rotor) and see if it wiggles

For a thorugh exam, you should pull the rotor and check the gear face (where the starter clutch rides) and confirm that the three bolts that hold the starter clutch to the rotor are tight. If they are loose, replace them with grade 8.8 bolts and locktite

Mine had been making the classic start up WHACK every once in a while and I found my bolts loose, the gear face hammered and one of the needle bearings broken.

[Roostabunny]

You didn't check everything on the starter side

Grab the starter clutch (the part between the big gear and the rotor) and see if it wiggles

For a thorugh exam, you should pull the rotor and check the gear face (where the starter clutch rides) and confirm that the three bolts that hold the starter clutch to the rotor are tight. If they are loose, replace them with grade 8.8 bolts and locktite

Mine had been making the classic start up WHACK every once in a while and I found my bolts loose, the gear face hammered and one of the needle bearings broken.

OK, appreciate that, Big T.

I'm chuckling at how casually you slipped "pull the rotor" in there. My sense is that epic poems have been written about the job contained in those three words. But, it seems it needs to done.

I'm working on that, but in the meantime, just checking my work. I've grabbed the starter clutch - No wiggle at all. I've posted pics for general edification and to make sure I'm looking at the right thing.

All the threads I found about flywheel removal seem to reference 1000's and bigger engines. I don't have welding tools, any tips on whether I can remove my rotor (1981 GS850) with a big bolt or existing part of my bike once I get that bolt out?

[Roostabunny]

Cool - after another round of searching I found this glorious post. Then I realized too late that I probably should have just asked Bwringer up front how he does it - it's not like I didn't know he's got an 850.

My local ACE hardware closes at noon on Saturdays, which is always an adventure on wrenching days, but I found the post just in time to get there 60 seconds before they started pulling in the display tricycles and got my "remover tool" bolts.

So, going to see what I can do on that bolt with wrenches and wood blocks while I wait for a local friend to tell me if I can borrow an impact wrench.

[Roostabunny]

Bolt out - And I kinda feel like it didn't live up to the hype. Course, the last crank bolt I removed was the crank pulley bolt on my wife's Honda Pilot. Yikes, that one nearly killed me.

The arrangement below was all it took for this bolt. I had a 24" length of black pipe on standby, but didn't need it.