Occasional clanking sound
11-06-2009, 12:46 AM
#1
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Occasional clanking sound
Hello,
Ok, I think I've finally gotten my carbs in working order. There seems to be only one problem left with my bike. Occasionally there is a "clank" or "clang" sound coming from the engine. It is infrequent, and almost entirely random, except that it happens more frequently when I first start riding the bike. I generally let it warm all the way up to 160 degrees before I ride, and it rarely gets above 180 degrees, so I don't think it's a warm-up issue. But somehow actually riding for a while seems to reduce - but not eliminate - it.
It really does sound like a "metal" sound. There is even a tiny bit of a ring to it, as if something metal is resonating as a result of being struck. However it could be the frame resonating, not whatever is causing the actual sound.
It is really making me nervous - it definitely sounds and feels like metal disagreeing with metal. When it happens there is substantial power reduction that is exactly as brief as the sound itself.
Background details: My bike is bone-stock except for micron exhaust. It has only a thousand miles on it. It sat for a year and a half without being properly prepped for storage with the previous owner. I just bought it and overhauled the carbs myself. Actually they were so gunked up that that didn't really work very well, so I ended up putting a different pair in that I got from indierocker. The sound happens with both carbs, though it is much less frequent with the new carbs. I am told the bike ran perfectly before, so the cause is either the sitting or the carb work I did. I just gave it an oil & filter change w/ 10-40 Mobile "3000" I think.
I know this is not the same as "being there" but here's a small audio clip of it for what it's worth: http://archive.est.org/tmp/clanking.mov.
I've done quite a bit of searching here, and the only theories I've come up with so far is CCT's or maybe just a bad cam chain itself. A friend of mine's theory is that something is not gettting properly lubricated. I considered valve clearance at first, but it seems to me that if that were making a sound, it would be nearly constant, not so occasional.
I'd appreciate any perspective/experience before I go ripping my bike apart in search of ghosts.
Thanks!
Ok, I think I've finally gotten my carbs in working order. There seems to be only one problem left with my bike. Occasionally there is a "clank" or "clang" sound coming from the engine. It is infrequent, and almost entirely random, except that it happens more frequently when I first start riding the bike. I generally let it warm all the way up to 160 degrees before I ride, and it rarely gets above 180 degrees, so I don't think it's a warm-up issue. But somehow actually riding for a while seems to reduce - but not eliminate - it.
It really does sound like a "metal" sound. There is even a tiny bit of a ring to it, as if something metal is resonating as a result of being struck. However it could be the frame resonating, not whatever is causing the actual sound.
It is really making me nervous - it definitely sounds and feels like metal disagreeing with metal. When it happens there is substantial power reduction that is exactly as brief as the sound itself.
Background details: My bike is bone-stock except for micron exhaust. It has only a thousand miles on it. It sat for a year and a half without being properly prepped for storage with the previous owner. I just bought it and overhauled the carbs myself. Actually they were so gunked up that that didn't really work very well, so I ended up putting a different pair in that I got from indierocker. The sound happens with both carbs, though it is much less frequent with the new carbs. I am told the bike ran perfectly before, so the cause is either the sitting or the carb work I did. I just gave it an oil & filter change w/ 10-40 Mobile "3000" I think.
I know this is not the same as "being there" but here's a small audio clip of it for what it's worth: http://archive.est.org/tmp/clanking.mov.
I've done quite a bit of searching here, and the only theories I've come up with so far is CCT's or maybe just a bad cam chain itself. A friend of mine's theory is that something is not gettting properly lubricated. I considered valve clearance at first, but it seems to me that if that were making a sound, it would be nearly constant, not so occasional.
I'd appreciate any perspective/experience before I go ripping my bike apart in search of ghosts.
Thanks!
11-06-2009, 04:33 AM
#3
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i had a small rattle clank last time i rode, thought it was my cam chain tensioners acting up, turned out my chain was hitting the exhaust, worth a peek see if your chain is rubbing on anything
11-06-2009, 06:14 AM
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Yes, it is a car oil. The owner's manual says API SG or higher. The oil says "API SM/CF SL,SJ,SH,SG" - and also says the oil must not say "energy conserving," which this oil does not say.
I thought they oil saying "SG" in that list meant that I was all set w/ the API SG requirement in the owner's manual.
11-06-2009, 07:29 AM
#5
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When the marketing DooDs decided they could charge more $$ for "Motorcycle Specific" oil!
If it ain't labeled "Energy Conserving", you're good to go.
As to your noise, I listened to the sound clip and have no clue.
Was the engine idling when it made the noise in the clip?
Rex
11-06-2009, 10:16 AM
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It sounds like a carb fart, but it doesn't feel like one. You can actually feel a slight shock go through the bike when it happens.
I talked to my dealer, and he agrees, the oil I used is fine. It's only a problem if it has some molybdenum additive that synthetics usually have. The irony is I had a friend pick it up for me and I told him to get Mobil 1 - but amidst checking all the other details (primarily the SF/GM SG whatever whatever), he spaced and didn't get M1. So I lucked out on that one.
I checked my chain, it's a little loose, right around 2" of play, so I do need to fix that. I wonder if my chain just needs to be lubricated, maybe a link in there somewhere is kinking a little, but not always?
Someone asked if the sounds were happening at idle. I don't think so, I think it was 2k or 3k rpms.
I talked to my dealer, and he agrees, the oil I used is fine. It's only a problem if it has some molybdenum additive that synthetics usually have. The irony is I had a friend pick it up for me and I told him to get Mobil 1 - but amidst checking all the other details (primarily the SF/GM SG whatever whatever), he spaced and didn't get M1. So I lucked out on that one.
I checked my chain, it's a little loose, right around 2" of play, so I do need to fix that. I wonder if my chain just needs to be lubricated, maybe a link in there somewhere is kinking a little, but not always?
Someone asked if the sounds were happening at idle. I don't think so, I think it was 2k or 3k rpms.
11-06-2009, 11:15 AM
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Replace the chain if you have the slightest doubt about it. You do not want to throw a chain whilst on the move. Clean it thoroughly, lube it with proper chain lube, and then adjust it to spec (35mm of slack). Check the slack at several points.
If there is a tight link and it is not bending as it goes around the front sprocket you will feel it through the feet as you are riding.
If there is a tight link and it is not bending as it goes around the front sprocket you will feel it through the feet as you are riding.
11-06-2009, 11:56 AM
#10
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Good lord almighty. Car oils have zinc and other additives that damage the clutch of motorcycles. Use only oil that you buy at your motorcycle dealer and you will be fine..... in the future. As for any damamge that's already been done, you might need to replace the clutch to fix it.
11-06-2009, 05:47 PM
#11
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Yep, it's a carb fart. The reason you feel it through the whole bike is because that backfire causes a small shock in the airbox. The airbox touches the tank (through foam) and is connected loosely to the rest of the bike via hoses.
You're running lean somewhere, and probably need to tweak the carbs just a bit more.
Was that an aftermarket exhaust I heard? If so have you rejetted? At a minimum, adjust the mixture screws to 2.25 turns out and shim the needles if there's no kit in it.
And a good carb sync never hurt either.
You're running lean somewhere, and probably need to tweak the carbs just a bit more.
Was that an aftermarket exhaust I heard? If so have you rejetted? At a minimum, adjust the mixture screws to 2.25 turns out and shim the needles if there's no kit in it.
And a good carb sync never hurt either.
11-15-2009, 07:00 AM
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You're running lean somewhere, and probably need to tweak the carbs just a bit more.
Was that an aftermarket exhaust I heard? If so have you rejetted? At a minimum, adjust the mixture screws to 2.25 turns out and shim the needles if there's no kit in it.
And a good carb sync never hurt either.
Was that an aftermarket exhaust I heard? If so have you rejetted? At a minimum, adjust the mixture screws to 2.25 turns out and shim the needles if there's no kit in it.
And a good carb sync never hurt either.
I have since put factory exhaust on, and synced the carbs. Before syncing, w/ just the factory exhaust, the clunk was happening quite a bit less. After syncing, I don't think it has happened once in about 35 miles.
Tweaking the mixture screws sounds like a good idea. Now I'll have to get one of those silly tools. How does 2.25 turns compare to the factory setting?
11-19-2009, 11:30 AM
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[/QUOTE] the mixture screws sounds like a good idea. Now I'll have to get one of those silly tools. How does 2.25 turns compare to the factory setting?[/QUOTE]
unless you're AR about keeping everything OEM, you can coax it out with a modified tweezers/other and dremel a slot for screwdriver adjustment.
unless you're AR about keeping everything OEM, you can coax it out with a modified tweezers/other and dremel a slot for screwdriver adjustment.
Last edited by nath981; 12-15-2009 at 04:01 PM.
11-19-2009, 10:32 PM
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HAHA good one. I came here thinking I was going to be an all OEM guy. I've barely had the bike a month, only really running for two weeks, and I've already done the TPS mod and shimmed my needles. And since I totally *bought* the friggin' dremmel just to do the TPS screws, it'd be nice to get another use out of it.
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