SuzukiSavage.com - Noise when coasting, belt tension concerns

Kiran

Ex Member

Noise when coasting, belt tension concerns
04/27/12 at 05:10:38

I just bought my 2012 S40, I have 150 miles on it so far. Right from the start I noticed a very loud whining/rubbing noise when I would decelerate or coast, it's constant regardless of the engine speed, and sounds like the final output shaft to me. I turned right around and went back to the dealer, who rode the bike for a minute and told me it's normal and once the bike is broken in it would go away. Well, I rode the bike for about 50 miles, and it just got worse. It is LOUD, especially if I were to coast from about 50 mph. Like a 'yang-yang-yang-yang' sound. It's not a sound made by the pulley and belt teeth meshing, I don't think.

So I went back to the dealer, told them this is unacceptable. First they insisted it's due to the break-in, but then another mechanic said it was because the belt wasn't tight enough. Personally I thought the belt was too tight to begin with, but they tightened it more. (I didn't know about that plunger in the tool kit, and I've read here that it's not good to go by that, but at the moment the belt is so tight only the first mark on the plunger shows.) Anyway, tightening the belt did make the sound go away, somewhat. I really think something's wrong with a bearing or.. I donno what.

Is this sound I'm describing normal for the S40? Or all belt-driven bikes?? The dealer would have me believe all bikes make this noise. I know better.

I'm going to try and record the noise with my cell phone in my pocket to see if it picks it up, then I'll try adjusting the tension of the belt and slacken it some. Judging by the 90 degree twist video, mine is way too tight. I can pluck mine like a guitar string. Shocked

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Kiran Ex Member	Re: Noise when coasting, belt tension concerns Reply #1 - 04/27/12 at 07:06:00 I've tried loosening the belt (took 1-1/2 turns of the adjusters.) Now the noise is as loud as it was to begin with. Here's a mp3 of the sound. http://dl.dropbox.com/u/180172/noise.mp3 First run is a coast from about 45. The 2nd is just cruising at about 30.
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Serowbot

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Re: Noise when coasting, belt tension concerns
Reply #2 - 04/27/12 at 08:08:50

Belt noise is very common...

Different people have solved it different ways... a dressing or coating can help for while,... I bevelled the edges with an angle grinder (permanent fix)(probably void your warranty)...
As a compromise,.. try lightly scuffing the belt edges with some coarse sandpaper...(I used to do that and it works pretty well)... or coatings of dressing or lube...

This belt is industrial grade, and much wider and stronger than a Harley belt,... it's a great belt, but noisy...
Factory tension is too tight. I know a guy, had his bike slowing down on bumps from the belt being over-tightened and restricting travel.
Here's how tight I do mine...
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1335401723

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Oldfeller--FSO

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Re: Noise when coasting, belt tension concerns
Reply #3 - 04/27/12 at 08:53:19

When the belt is new, the pulleys are new, the teeth are a light interference fit and make noise going into and out of mesh. This is most apparent on decel as engine noise is less.

Put some miles on it and it will go away.

Backside is a condition to look out for when you have much higher mileage (20,000 or more) is when the splines on the front pulley get loose and start to make a similar but much more metallic noise. That is when you do the remove clean goop and retorque on the front pulley nut and shaft splines.

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Kiran

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Re: Noise when coasting, belt tension concerns
Reply #4 - 04/27/12 at 09:52:34

Thank you for the replies. I hope it does go away because, to me, after spending $6K on a bike, I don't think I should have to listen to that noise all the time.

I went back to the dealer this morning, and they re-tightened the belt (after I loosened it) which just seems to mute the noise, but doesn't get rid of it. If I had known these make this noise I would have looked at something else.

But to you gurus; if my little mp3 sounds 'normal', then I'll take your word for it, of course.

(At about 30 seconds is when it's the most obvious.)

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Savage_Rob

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Re: Noise when coasting, belt tension concerns
Reply #5 - 04/27/12 at 09:55:47

Oldfeller--FSO wrote on 04/27/12 at 08:53:19:

When the belt is new, the pulleys are new, the teeth are a light interference fit and make noise going into and out of mesh. This is most apparent on decel as engine noise is less.

Put some miles on it and it will go away.

Makes sense. I guess I never noticed it because mine already had a few miles (1640) when I bought her.

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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28653 Tucson Az Gender:	Re: Noise when coasting, belt tension concerns Reply #6 - 04/27/12 at 09:55:56 Just listened... That's typical belt whine... (bugs the heII out of me)... Like I said,.. if it bothers you, coarse sandpaper the belt edges... ...
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Kiran Ex Member	Re: Noise when coasting, belt tension concerns Reply #7 - 04/27/12 at 10:00:06 Serowbot wrote on 04/27/12 at 09:55:56: Just listened... That's typical belt whine... (bugs the heII out of me)... Like I said,.. if it bothers you, coarse sandpaper the belt edges... ... Ok! Thank you. I just wanted someone to hear it and say yea or nay.
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Savage_Rob Serious Thumper Alliance Member Offline Mechanically Inclined Amateur Posts: 6972 Texas (Dallas area) Gender:	Re: Noise when coasting, belt tension concerns Reply #8 - 04/27/12 at 10:09:31 If it were me, since the tension has been played with... I'd suggest using the method shown on this site to make sure it's tensioned and centered properly.
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Noise when coasting, belt tension concerns Reply #9 - 04/27/12 at 10:28:33 Absolutely,, get the initial wear patterns even , adjust it now.
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AlphaBarney

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Re: Noise when coasting, belt tension concerns
Reply #10 - 04/28/12 at 07:32:32

If it's centered and the tension is okay maybe try a little silicone spray/lube as a belt dressing after a good cleaning. Read that somewhere on here, tried it and the noise hasn't come back yet. Probably a temp fix, but applying a little now and then is easier than cleaning and lubing a chain all the time, so meh.

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Kiran

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Re: Noise when coasting, belt tension concerns
Reply #11 - 04/30/12 at 10:33:19

I read on another forum where they're measuring the belt tension with a guitar tuner. There's a android app called gStrings that's free. I wonder if someone with a properly tensioned belt could measure the frequency if they pluck it? I didn't really pay attention to the frequencies they discussed because it was for Ducatis.

They also said twisting the belt 45 degrees (not 90) was the other way to test the tension. Again, on a Ducati.

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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28653 Tucson Az Gender:	Re: Noise when coasting, belt tension concerns Reply #12 - 04/30/12 at 10:42:42 I think that's a timing belt on a Ducati,.. not a drive belt... If my drive belt had a frequency,.. it would resemble an old horse fart... It's pretty loose... ... don't think there's an app to measure that......
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Noise when coasting, belt tension concerns Reply #13 - 04/30/12 at 10:49:27 an old horse fart. I wish I didnt think I know the sound youre trying to describe.
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Kiran Ex Member	Re: Noise when coasting, belt tension concerns Reply #14 - 04/30/12 at 17:15:12 Here's the thread. http://www.ducati.ms/forums/56-superbikes/105833-belt-tension-tips-tricks-nee...
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