Whilst doing the Lewes bypass yesterday morning (having just emerged from a
miserable few miles of freezing fog) on my '93 Trident 900, at about 80mph I
became aware, above the wind noise, of a screeching sound coming from below,
not unlike a small electric motor being over-revved and its bearings
complaining.

This has happened a few times before, but it's extremely difficult to tell
exactly where the noise is coming from, because it doesn't happen at lower
speeds and I can't very well lean down and listen more closely when
barrelling along at fairly high speed. It definitely seems to be related to
road speed rather than engine revs, because the noise continues if I shut the
throttle and declutch, but stops when I get below 50 or 60 mph.

I'm wondering if it might be the speedo cable or speedo drive?

Has anyone else encountered anything like this and can offer wise counsel?

Thanks...

--
Andy Clews
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In communiqué <(E-Mail Removed)>,
(E-Mail Removed) cast forth these pearls of wisdom
>Whilst doing the Lewes bypass yesterday morning (having just emerged from a
>miserable few miles of freezing fog) on my '93 Trident 900, at about 80mph I
>became aware, above the wind noise, of a screeching sound coming from below,
>not unlike a small electric motor being over-revved and its bearings
>complaining.
>
>This has happened a few times before, but it's extremely difficult to tell
>exactly where the noise is coming from, because it doesn't happen at lower
>speeds and I can't very well lean down and listen more closely when
>barrelling along at fairly high speed. It definitely seems to be related to
>road speed rather than engine revs, because the noise continues if I shut the
>throttle and declutch, but stops when I get below 50 or 60 mph.
>
>I'm wondering if it might be the speedo cable or speedo drive?
>

Sounds a likely culprit. The speedo drive gear jobbie on my Morini
rumbles a bit when you spin the front wheel on a stand, but you can't
hear anything for the row from the 2:1 pipe once under way. Is the
speedo wheel or gearbox driven?


--
+-------------------------------------------------------------------+
| Pete Fisher at Home: (E-Mail Removed) |
| Aprilia Shiver Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 |
+-------------------------------------------------------------------+

(E-Mail Removed) wrote:
> Whilst doing the Lewes bypass yesterday morning (having just emerged from a
> miserable few miles of freezing fog) on my '93 Trident 900, at about 80mph I
> became aware, above the wind noise, of a screeching sound coming from below,
> not unlike a small electric motor being over-revved and its bearings
> complaining.
>
> This has happened a few times before, but it's extremely difficult to tell
> exactly where the noise is coming from, because it doesn't happen at lower
> speeds and I can't very well lean down and listen more closely when
> barrelling along at fairly high speed. It definitely seems to be related to
> road speed rather than engine revs, because the noise continues if I shut the
> throttle and declutch, but stops when I get below 50 or 60 mph.

Does the note tone rise and fall linearly with speed (gearbox etc ?) or
does it just rise or fall in volume (aerodynamic whistles).

--
03 GS500K2
78 Honda 400/4 in black
98 Yamaha YP250 Majesty

(E-Mail Removed) wrote:

> Whilst doing the Lewes bypass yesterday morning (having just emerged
> from a miserable few miles of freezing fog) on my '93 Trident 900, at
> about 80mph I became aware, above the wind noise, of a screeching
> sound coming from below, not unlike a small electric motor being
> over-revved and its bearings complaining.
>
> This has happened a few times before, but it's extremely difficult to
> tell exactly where the noise is coming from, because it doesn't
> happen at lower speeds and I can't very well lean down and listen
> more closely when barrelling along at fairly high speed. It
> definitely seems to be related to road speed rather than engine revs,
> because the noise continues if I shut the throttle and declutch, but
> stops when I get below 50 or 60 mph.
>
> I'm wondering if it might be the speedo cable or speedo drive?
>
> Has anyone else encountered anything like this and can offer wise
> counsel?
>
> Thanks...

Alternator [1] bearing?

[1] Dunno if your trumpet even has an alternator, but I had this happen
many years ago on a 1977 Honda Civic. Took ages to find the culprit;
it was completely seized.


--
Nothing relevant

Thus spake Pete Fisher ((E-Mail Removed)) unto the assembled multitudes:

>>I'm wondering if it might be the speedo cable or speedo drive?

> Sounds a likely culprit. The speedo drive gear jobbie on my Morini
> rumbles a bit when you spin the front wheel on a stand, but you can't
> hear anything for the row from the 2:1 pipe once under way. Is the
> speedo wheel or gearbox driven?

Wheel. Two years ago I sliced through the cable when I (*blush*) forgot
that I had a disk lock attached to the front disk. Drivers were beeping me
and frantically pointing at the hanging cable on my way home, thinking that
it was my brake :-)

--
Andy Clews
*** Remove DENTURES if replying by email ***

Thus spake (E-Mail Removed) ((E-Mail Removed)) unto the assembled multitudes:

>> barrelling along at fairly high speed. It definitely seems to be related to
>> road speed rather than engine revs, because the noise continues if I shut the
>> throttle and declutch, but stops when I get below 50 or 60 mph.

> Does the note tone rise and fall linearly with speed (gearbox etc ?) or
> does it just rise or fall in volume (aerodynamic whistles).

Bit of both, but not by much. The sound, once it starts, is a fairly
constant note and it's not often immediately apparent because of wind and
engine noise. And below a certain speed, it just stops. It only ever seems
to be that stretch of road where it happens, but I know that's a bit of a
daft correlation. At that point I have done 13 miles from home, so I'm sure
it would happen anywhere else at a similar speed after a similar distance;
it's just that riding it to work is my most frequent journey.

--
Andy Clews
*** Remove DENTURES if replying by email ***

(E-Mail Removed) wrote:

> Thus spake (E-Mail Removed) ((E-Mail Removed)) unto the
> assembled multitudes:
>
> >> barrelling along at fairly high speed. It definitely seems to be
> related to >> road speed rather than engine revs, because the noise
> continues if I shut the >> throttle and declutch, but stops when I
> get below 50 or 60 mph.
>
> > Does the note tone rise and fall linearly with speed (gearbox etc
> > ?) or does it just rise or fall in volume (aerodynamic whistles).
>
> Bit of both, but not by much. The sound, once it starts, is a fairly
> constant note and it's not often immediately apparent because of wind
> and engine noise. And below a certain speed, it just stops. It
> only ever seems to be that stretch of road where it happens, but I
> know that's a bit of a daft correlation. At that point I have done
> 13 miles from home, so I'm sure it would happen anywhere else at a
> similar speed after a similar distance; it's just that riding it to
> work is my most frequent journey.

Either speedo drive or wheel bearing getting squeaky when hot. Try
popping the speedo cable off & squirting some spray grease in the drive
hole. If it takes longer for the noise to appear, there's your answer.

--
Krusty

Raptor 1000 MV 750 Senna Tiger 955i Tiger 885 Fantic Hiro 250

Dan L wrote:

> (E-Mail Removed) wrote:
>
> > It
> > definitely seems to be related to road speed rather than engine
> > revs, because the noise continues if I shut the throttle and
> > declutch, but stops when I get below 50 or 60 mph.
>
> Alternator [1] bearing?

Highly unlikely given the above. The standard failure mode for early
Trumpet alternators is a rattle[1] not a squeal.

[1] Known as 'DAR' - Deathly/Deafening Alternator Rattle.

--
Krusty

Raptor 1000 MV 750 Senna Tiger 955i Tiger 885 Fantic Hiro 250

"Krusty" <(E-Mail Removed)> wrote:
> (E-Mail Removed) wrote:
>
> > Thus spake crn unto the
> > assembled multitudes:
> >
> > >> barrelling along at fairly high speed. It definitely seems to be
> > related to >> road speed rather than engine revs, because the noise
> > continues if I shut the >> throttle and declutch, but stops when I
> > get below 50 or 60 mph.
> >
> > > Does the note tone rise and fall linearly with speed (gearbox etc
> > > ?) or does it just rise or fall in volume (aerodynamic whistles).
> >
> > Bit of both, but not by much. The sound, once it starts, is a fairly
> > constant note and it's not often immediately apparent because of wind
> > and engine noise. And below a certain speed, it just stops. It
> > only ever seems to be that stretch of road where it happens, but I
> > know that's a bit of a daft correlation. At that point I have done
> > 13 miles from home, so I'm sure it would happen anywhere else at a
> > similar speed after a similar distance; it's just that riding it to
> > work is my most frequent journey.
>
> Either speedo drive or wheel bearing getting squeaky when hot. Try
> popping the speedo cable off & squirting some spray grease in the drive
> hole. If it takes longer for the noise to appear, there's your answer.
>
>
If it's cable driven, why not leave it disconnected completely while you
test it?

Thus spake Krusty ((E-Mail Removed)) unto the assembled multitudes:

>> Alternator [1] bearing?

> Highly unlikely given the above. The standard failure mode for early
> Trumpet alternators is a rattle[1] not a squeal.

> [1] Known as 'DAR' - Deathly/Deafening Alternator Rattle.

I should add that the noise is not quite a squeal, but not really a rattle
either. And as I said, it's related to road speed rather than engine revs so
surely is unlikely to be the alternator. I bloody hope not anyway. Very
difficult to describe really. It's a bit like the sound of an elephant
trumpet (how appropriate!), and maybe like the sound of a loud brake squeal
like you often hear from large trucks or buses. Just imagine it as a long
drone rather than a short burst of sound. If only I could record it and put
it online somewhere...

--
Andy Clews
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