What is that noise in top gear???

redpaso · Post by **redpaso** » Tue Oct 03, 2006 4:55 am

Ahoy all technically minded Pasophiles.

I have been riding the Paso to work occassionally lately (the long way naturally) as Spring has Sprung here in the South & it is too good not to ride "The Mistress" when I can. I have had her apart a bit lately with Carb & then Thermostat problems.

I have noticed a funny thing that is causing me some concern. When I slot her into sixth gear I hear a sound that is a bit like someone riding a pushbike beside me with a card in the back spokes (remember doing that as a kid?) it is only faint but it is definately there & as soon as I change down it goes. She is running like a dream & performance is not affected in any way.

Any ideas as to what is going on here?
I am assumming that it is gearbox as it is related directly to gear selection. It does not occur in any gear other than sixth. Could there be a fine spring or washer that is touching on the cog teeth?

Some advise before I pull her apart again would be really appreciated.

ducapaso · Post by **ducapaso** » Tue Oct 03, 2006 5:44 pm

unluckly there's no sixt gear in my dukess (750 engine) I think that first thing to do is search iron powder in the oil of your engine... I know that's usual find this, (well known as "italian character") but it's in reference to the kilometrage of the oil itself... Any wrong work of the gear (such as broken teeth in 6th gear) will produce iron powder. However a great deal of thing can cause this noise!
Air intake, chain "chattering", aerodinamic flow in the bodywork....
Good search!

streetsurfer · Post by **streetsurfer** » Tue Oct 03, 2006 8:40 pm

I hope for you, it is something simple like sprocket or chain. A piece of cork or rubber between the chain guide and swingarm may quieten it if it is chain noise. The hollow swing arm resonates any chain slap noise and maybe it is only at 6th gear speeds that you can detect it. Just my thought, as I did the same fix to my KTM. I sure hope it is not internal. You might look for marks where the chain may have been hitting the arm.

redpaso · Post by **redpaso** » Wed Oct 04, 2006 5:01 am

ducapaso wrote: However a great deal of thing can cause this noise!
Air intake, chain "chattering", aerodinamic flow in the bodywork....
Good search!

I have recently drilled the intake side of my airbox (fortunately I have a spare that remains undrilled). Could this be the cause of my mystery noise? I noticed yesterday riding home that the noise remains when acceleration is lifted off but it is broken & not as constant as under acceleration. I will check this again tomorrow on the way to work. can you please provide more information as to how air intake could be causing this noise?

streetsurfer · Post by **streetsurfer** » Wed Oct 04, 2006 5:21 pm

I think you could gage the intake noise by throttling it up while parked-without it in gear or maybe even with some body work off to get a better idea. When I opened my intake and later installed the K&N, the noise increase was sort of like a loud snore or a gargeling sound. . I have the Weber. Maybe dual carbs do sound more like a card in the spokes. What are you breathing through?

I realize it could be other things too but this also falls in line with chain slap...hearing it when off the throttle, coasting. Are your sprocket teeth kind of fish hooked or the chain stretched? If so it could be lifting off the front sprocket and hitting the guide around it.

ducapaso · Post by **ducapaso** » Thu Oct 05, 2006 5:24 am

air intake can cause very unusual and unintelligible noises... just try to install the undrilled airbox and test the modify...
Any upgrade has to be tested on the road to show its real utility

redpaso · Post by **redpaso** » Thu Oct 05, 2006 9:27 pm

I am running the Weber very happy with it. Since drilling the intake It has taken on a new persona, you definately hear it sucking in the air, I will swap to the undrilled cover & test. The chain & sprockets have only 1000 Km on them & tension is good.

I will check on the weekend & keep you posted,

Thanks guys

JWilliam · Post by **JWilliam** » Wed Oct 11, 2006 5:07 pm

Noising from the 6th gear only is almost certainly a worn pair of gears. Suprising that it is 6th gear, you would expect 2nd or 3rd. Just wear ear defenders and ride normally, when it goes "clonk" and locks up the rear wheel you will be able to identify the fault all the more easily. Has the noise got a vibration? Has it become worse during the past few weeks? Splitting the crankcase should reveal ground metal surfaces or worn gears.

jomo · Post by **jomo** » Tue Oct 24, 2006 11:48 am

Red,

I'll be up there soon, I'll contact you....maybe bring my stethescope(hope I spelt it correctly!). Hope it's not a chipped gear, they usually go bang very quickly :thumbdown:

My brother-in-law is possibly your milkman (Stuart) and owns an ST2. and lives at Bootawa, but his area is more towards wingham.

John

Finnpaso · Post by **Finnpaso** » Wed Oct 25, 2006 6:15 pm

MILKMAN with Ducati ST2 ???? CANT WAIT foto !!!! Any? :funny: :funny: :funny:

redpaso · Post by **redpaso** » Tue Oct 31, 2006 11:45 am

Hey John, I don't have a Milko, to tight & go get it myself. Is that the Blue ST getting round town? I don't think i know him but if that is his bike I have seen it on the back wheel up the main street on a Saturday Morning, looked impressive! Definately let me know when you are comming this way (hopefully you are on the Paso) I am keento catch up & please bring your stethescope

duckboy · Post by **duckboy** » Sun Jan 20, 2008 12:22 pm

have you solved the mystery noise yet?
sounds to me like a chipped gear.
only the outer metal is hardened, and they are soft on the inside, so when they go, they disintergrate quite rapidly. I hate to be a prophet of doom, but check your enigne oil for metalic particles.