Saturno Bialbero Mid range rattle

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John Ward
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Saturno Bialbero Mid range rattle

Post by John Ward » Wed May 11, 2016 8:57 am

Hi

I am a new member here and a new owner of a 89 Gilera Saturno - a Jap import showing 16,000 km on the odo (could be real on the basis of the bike presentation)

Its a Great Bike I can tell - feels good on the tight roads here (Northern NZ) and strong performance for a 500 single - I have done just 200 km so far.

There is an issue though - there is quite a bit of mid range engine rattle 3000 - 5000 RPM, typically this is during deceleration or when the throttle is just cracked open.
If you open the throttle full at 3000 RPM you don't get the rattle of any serious order (but it may feel a little lumpy as it goes through 3000 - 4000 RPM range - as it might anyway?)

The engine idles quietly and is very smooth from 5000 RPM going to the redline smoothly easily.

When I bought it there was a carb issue identified during the test ride (Main Jet/Needle) which coincidentally gave issues in the same troubled rev range as the rattle - the carb was fixed by a mechanic working for the seller though it then and highlighted the rattle issue. The mechanic working for the guy that sold the bike told me that the rattle was the tank baffle which was loose (it seems to be) -However I have run it with another bike tank on and the rattle remains and even without a tank and no joy.

I am thinking maybe piston slap (Though it burns no oil and compression seems good) or maybe cam rattle.

Any ideas?

Can you remove the head etc without removing the engine?

I might pull the upper engine apart as a start but am pondering letting it develop too.

Guess I might at least be checking out parts availability for gasket sets/pistons etc - any recommendations?

BTW - I took a look under the timing cover and it appears good to me.

Any comments appreciated.


Cheers




John

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oekotopia
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Re: Saturno Bialbero Mid range rattle

Post by oekotopia » Wed May 11, 2016 9:18 pm

:D
Hi John
I'm no Saturno driver but from the XRT or Nordi I know a method.
You loosen the Nuts at the Zylinderhad a little,then Conter it with
a second nut and remove the Zylinderbolt,after 4 bolts you can
remove the Zylinderhad to the side, :wink:
best regards
Georg
Trap ist kein Pferdesport

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Joachim
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Re: Saturno Bialbero Mid range rattle

Post by Joachim » Thu May 12, 2016 6:02 pm

long distance remote Gilera tuneups are still at beta state :)

As HP tells, the Saturnos are not one of those long stroke tracktor single cylinders like the old style Horex have been.
Reving up is not a bad idea :)

What makes me wondering is, you wrote .... typically this is during deceleration....
Issues with the engine should be noticed first under heavy load, i think.

The problem with the 'shit' metall piece in the fuel tank is also well know here.
But the noise this thing will make when it's broken is that loud that you will stop at once to see what's wrong.

Another thing which is not very common is the noise of the full floater front brake disc.
First time i heard this i stopped to have a look ;)
But this will appear due to bad road conditions.
And you should notice that the source of the rattle comes more from the front area.

So it will be a good idea to check first what HP has mentioned to make shure that there is no serious problem with the engine.
Maybe that there is a part somehwere which is resonating within a specific range of revs.
Mayb it would be wort h to check all parts wether they are well monted or not.

Did you know the british gilera forum at http://www.gilera.org.uk/Joomla/
As far as i remember the member and former Saturno owner Paul has moved to NZ.
Maybe he is somewhere close to you to have a look.
And i think that there are some more members from NZ.

Last but not least, did you have a workshop manual?

ciao Joachim
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John Ward
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Re: Saturno Bialbero Mid range rattle

Post by John Ward » Sat May 14, 2016 4:04 am

Thanks everyone for the input, some useful info here - I would have responded earlier but was waiting for confirmation that the post had been accepted and it never came - did it get sent or end up in the spammer?

The rattle is sorted and not what I expected or what I could have envisaged - It turned out to be a slightly loose (very slightly) headlamp that rattled at resonance frequency and the noise was somehow amplified in the fairing, I had been all over the bike several times looking for this before it was found - It may be that the headlight/retainers are not original as there is a chrome rim forward of the fairing and this was the culprit and it doesn't look like the headlight in the photo's that I have seen on the web (though the bike appears largely original and doesn't seem to have been messed about with much if am reading what I see under the tank and seat correctly). Anyway I am pleased to have it sorted before I started pulling the engine down (I had the timing cover off and that's about it)

The Frame # is NH02............

Garagian/Joachim - I agree that the bike likes 4000 RPM + Maybe even 4500 RPM plus and it runs incredibly well and sound great above this range. I was only messing about trying to identify the rattle with the rev range (Throttle on full at 3000 RPM). Other impressions, It may be a tad overgeared I find as you need to be moving quite quickly before the bike likes to get into 5th - but maybe thats just the NZ roads where it's mainly the twisty stuff?
Yes you can cruise up 90 mile beach but I would not do it on my saturno (maybe on my triumph tiger - or more likely Scorpio as I don't mind salt with my fries but not my bikes - I actually did the cape Reinga run a few weeks back on the tar seal, recommend it to anyone as a classic biker run - I don't live that far north BTW, I am in Mangawhai about an hour north of Auckland

Thanks again everyone.

John Ward
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Re: Saturno Bialbero Mid range rattle

Post by John Ward » Sat May 14, 2016 4:22 am

One further thing after above:

When i received the bike the main jet was changed by a mechanic working for the prior owner as it was running rich (the old main jet was corroded) - I believe the new jet is a 128 - it seems to be running lean now based on spark plug inspection - clean plug but quite white - the engine runs in the correct temp range however. The plug is a NGK DPR 7EA9.

I am thinking of fitting a 138 main jet and maybe a harder plug - any recommendations.

John Ward
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Re: Saturno Bialbero Mid range rattle

Post by John Ward » Sat May 14, 2016 8:43 am

Thanks -auf Wunsch des Beitragserstellers geloescht-

I will give your recommended plug a go (assuming I can get it here) and see what I can get close to the main jet size that you suggest

Cheers



john

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Joachim
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Re: Saturno Bialbero Mid range rattle

Post by Joachim » Mon May 16, 2016 7:44 pm

John Ward wrote:I would have responded earlier but was waiting for confirmation that the post had been accepted and it never came - did it get sent or end up in the spammer?
Due to problems with heavy spam some years ago, Bjoern changed the registering to 'hand work'
If one tries to register i get an notice.
Next step is to unlock the user.
Now he get's a notice and can post an article.
But only the mod can read it and it needs to be unlocked again. You get the next notice.
Now it's possible to see wether you are a spammer or not ;)
So next step is to take you away from the list of the new users still under investigation :)
From this time on all your articles wil lappear in the forum at once and you will get no further notifications.
Just to explain the details
Maybe it would be worth to write a little exclaimer ;)
The rattle is sorted
rulez

We just had our anual meeting over this weekend.
2 had strange noise at their Nordies.
One might be the broken head light mount, the other is a broken mount at the front mud gard.
Last year i also had a strange noise at my Nordie. It turns out to be a broken exhaust clamp.
A.... and i could only hear that gentle wizzing while decelearating ;)

ciao Joachim
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John Ward
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Re: Saturno Bialbero Mid range rattle

Post by John Ward » Tue May 31, 2016 2:36 am

Joachim, Hi, I You stated above " Another thing which is not very common is the noise of the full floater front brake disc"

I just noticed the front disc rattle due to 'loose' fit/clearance on the 12 x 'barrel' mounting fasteners (looks like circlip held to the hub mounted fixed disc) - the fastening suggests the loose fit maybe by design (though a life in engineering has me alarmed at loose fits on rotating equipment) - I then considered your comment after searching the forum.

There is no information relating to this in the Gilera manual - e.g. limits etc - are there any checks to be made to verify the limits of the float?

BTW - I checked the disc thickness against the 4.5 mm - 5 mm tolerance specified in the manual @ 4.9 mm this seems to be good and suggests that the brake has not seen too much heavy work and probably normal for the odo stated 16 000 km

I did notice a sound that could be attributed to this this disc rattle while riding and was trying to identify it - light rattle with no consistency....... except maybe a regular "Clunk" when crossing a slow speed bump in the road.

Appreciate any comments

John Ward
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Joined: Sun May 08, 2016 7:23 am

Re: Saturno Bialbero Mid range rattle

Post by John Ward » Wed Jun 01, 2016 10:21 pm

Thanks HP

I have been considering limiting the axial float in a similar way to how you describe.

There appears to be a small amount or radial clearance (though have not measured as I have misplaced my feeler gauges!) and anyway there would need to be a small amount though the manual does not specify a tolerance.

At the moment I am not thinking of changing the disc though it would be useful to know where you procure them from - there are companies in NZ that would make me one up if I needed to.

Thanks again



John

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Re: Saturno Bialbero Mid range rattle

Post by agusta74 » Wed Jun 01, 2016 11:21 pm

It's a Kiwi take over of the list John!! lol
:)
Regards
Gavin

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