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Fork oil

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Ken-Guzzibear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 13:29
When i found the V1000 there were no bolts in the top of the forks !!!!! after a look at the manual I drained the oil & water out of the forks, left them draining for a few days, bought a then can of ATF  using a syringe flushed them then re filled ....No idea how long the top bolts had been missing but it had been stood at least 3 yrs, that was 30 yrs ago now, different Guzzisti mechanics have commented how good the front fork damping is ....as far as i am aware these are the oem ones from 1976. I have never swapped them ......The newer EV has no real advantages on the road .... As has been pointed out ATF is only for damping and due to it's properties does the job very well indeed 
The Older i Get, The Better I Was
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GC888 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GC888 Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 15:31
I'm all for experiment myself 

When I first looked at the pitting on mine I would have dumped them and grafted on something else with the same diameter. 

However people tend not to list front forks by diameter and scrap ones are hard to find due to the lack of motorcycles being written off by reversing into things !   

Glad to be of help Smile
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 18:10
Originally posted by TheWrongTrousers TheWrongTrousers wrote:

I wonder how you know that Mike ... ?

Yep I just stopped meself, I couldn't think why not take both out, then both could be draining to save a bit of time? It was just starting to pitch forward but I saved it. LOL



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TheWrongTrousers View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TheWrongTrousers Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 18:33
I feel better now I know that it is not only me who does things like that. My Laverda is fine if you take off the front wheel - it just sits up and tilts back nicely. After 25 years of that routine, it is something of an understatement to say that I was astonished when having the front wheel off - the Guzzi immediately made like a submarine diving forwards and downwards. Like you (and I hope most of us here) , I just managed to save it by skin of my teeth. Up periscope !

Edited by TheWrongTrousers - 18 Jan 2019 at 18:36
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George S View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote George S Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 21:09
Originally posted by GC888 GC888 wrote:

Yes its a bad idea 

The auto transmission fluid is much thinner and is less likely to act as a damper 
The design is that it splashes around lubricating but nothing more.  

If that was the full story you could just get away with using a very high quality fully synthetic 0-20 engine oil.... 

But don't - 

Engine oil has the ability to absorb water and release it when hot - the forks will never get hot so over time the oil will fail (the absorption seen in extreme cases is the mayonnaise you get when a head gasket leaks) 

In normal temperatures 0-20 has a higher viscosity than the thickest ATF the thinner ATF has an even lower viscosity. 

Normal fork oil at around 10 will still act to hydraulically damp the fork, I think it will be away off locking it but as ATF is not expensive why chance it .... 

  


Have been following this thread with interest.
I have a 1961 Moto Guzzi Zigolo 2 stroke. Manual recommends to use Shell SAE 20 oil.
Bike has been left standing for years. When I drained forks there was some water and rust spots.
Forks are very basic, springs plus tapered rod at bottom going into hole at bottom of stanchion with 2 return holes in stanchion leg. I think this was Moto Guzzi's first attempt at fork damping on small 2 strokes.
My question is should I use an ATF oil, SAE 10 fork oil or sae 20 gear oil
All recommendations greatfully received
George

1994 Nevada
1962 Lightweight ducati Bevel Single
Son's 1990 1000S to borrow any time
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 21:28
I would stick to what the manual says.
If the forks then feel stiff, try SAE 10. ATF would be too thin and might give no damping.
Brian.

Better 5 minutes late in this world than years early in the next.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote George S Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2019 at 21:45
Have just been reading Castrol Classic web site and they rcommend Castrol Classic TQF as an alternative to SAE 20 (I have been unable to source SAE 20)
 
"Suitable for use in motorcycle primary chaincases and front fork applications where Castrolite (SAE20) has been recommended."

As I have some TQF left from using in Ariel Sports Arrow primary case I will give it a try and see how if it works. Not a problem to change if not suitable
George

1994 Nevada
1962 Lightweight ducati Bevel Single
Son's 1990 1000S to borrow any time
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TheWrongTrousers View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TheWrongTrousers Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 11:29
I am somewhat surprised at the amount of ATF that goes in the forks. 0.12 litres which is 120ml. I measured that amount of water in a kitchen measuring jug and I just can't get over how little that seems. I keep thinking i have a decimal point in the wrong place. Is that really how much I should use in each leg ? It just seems like nothing at all !
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 12:25
If you put 1.2 litres in it would form a hydraulic lock as the fork leg would be full.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 14:26
As has been said several times, all it does is lubricate so doesn't need a great deal. In fact my manual (V50 II) states 0.07 litres ie 70cc per leg. Virtually nothing if you're used to the oil being the damping medium.
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 14:31
Yes it is only a thimble full. I think the T3 is 6cc.
I've been following this thread too, I didn't know about the reasoning against using engine oil in the forks. I was shocked to find that Honda say to put 10/40 in the forks on their CB175
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TheWrongTrousers Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 14:38
We live and learn Jerry. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 19:32
Originally posted by Brian UK Brian UK wrote:

If you put 1.2 litres in it would form a hydraulic lock as the fork leg would be full.


And yes I have done this. Didn't drain the Spada's properly one weekend, I thought it had none in it, as nothing much came out. Couldn't get the caps off or refill at the top so squirted it into the drain holes instead. Rode to work on Monday with solid front suspension. Ejected the excess in the carpark. LOL

I seem to have a figure in my head of 90cc for my LM1, but memory is erratic...





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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jan 2019 at 19:53
Same with my memory and it was only 2 or 3 years ago. I know the Haynes book of lies said something different to the Guzzi book of lies, i think one was 6cc the other 60cc. Perhaps put 6 in one side and 60 in the other
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpc Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan 2019 at 06:46
My own Guzzi Gospel (R.M.T.) says they issued a final technical bulletin in '76:
120 cc per leg for the LeMans, 60 cc per leg for all other Tonti 750s and 850s.
Oil type ATF Dextron with 3.6 Engler viscosity @ 50°C, and that falls in the SAE 10W range for motor oils, or SAE 75W range for gear oil  ( http://www.nadi.it/english/viscosita.htm ).

Why the LM fork should require twice as much is beyond me, but there you are...
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