850T 750S side panel locks

My locks are solid and do not turn. The key goes in and out (one side better than the other) so there is some movement internally but I suspect that the plungers and springs are corroded solid. I am trying WD but do not hold out too much hope. One was removeable from the side panel as the retaining screw head was visible but on the other side the locking arm is masking the screw head. I want both off (hopefully to restore and replace) so that I can repaint the side panels/tool boxes. Would ultrasonic cleaning help? Any ideas?

Best wishes

WD40 is my norm for bits like that, along with some warmth and plenty of patience. If they are currently sitting in a freezing cold garge, bring them in and sit them on a warm radiator. Keep applying the WD40 and moving the key back and forth to see if you can get a bit of movement.
A soak in an ultrasonic would certainly help with some warm cleaning solution. It might just get some of the corrosion moving.
Are there any identifying marks or writing on the lock to see if replacements are readily available? I would expect them to be a universal part bought in by the factory rather than a purpose made component.

Thanks Don, things have moved on a little today, rather than freeing the lock I managed to take the locking arm off both locks which was held in place by a pin through the collar on the arm and through the lock as well. Without the locking arm covering the screw that holds the retaining plate I was able to remove the screw and the retaining plate. So far so good. I now have both locks off. I then decided to remove one of the plates that hold the 4 springs and plungers in place. Ping! 3 of the 4 springs are on the floor. 30 minutes later I have located the springs. I turned the lock body over and tapped it on the workbench and 7 plungers (pin tumblers?) of different lengths fell out, I think there should be 8!

If I take the plate off the back of the other side of the lock (being careful to stop the springs flying around the room again) I will be able to measure the length and number of plungers in each of the 4 barrels. A job for the locksmith maybe? :unamused:

Being as it is a slow day here and too cold to spend long in the garage, I googled 750S side panels and came across a thread on this old tractor refering to Neiman locks, but it was loop frame rather than 750S. Would Guzzi change supplier?

Thanks Don, you area star. Things have moved on here I have found a locksmith who has taken them away to repair and restore. I will report on the results and the damage to my bank balance!

Now that I have got the locks off I can get the side panels/tool boxes repainted. I also have to de-rust the inside of the tank first and for that I have bought 1kg of deox C rust remover as recommended by someone on here a while back. I will give it a shot this weekend, and then the tank can go off to the painters with the side panels.

I am getting FD Motorcycles to do the painting, they have done all of my bikes, including the pin lines and eagles on the 750s, in the past. I have a hankering after green stripes again like it was when I first converted it from an 850T about 35 years ago!

Red was ok, but blue was a mistake!

I have used that Deox-C myself recently. I bought a 1kg tub of it and used it on the three Stornello tanks I’m working on and then dunked a really rusty old battery box into it and left it there for about a week. It certainly worked well. It has left it a bit mothy with a few holes that I will need to fill, but the rust has all gone.
I am planning on doing the S3 stripes on this one, but using the 3 colours of the Italian flag. The tank will be a darkish silver as in the side panel that I did a quick test on.

Moto Guzzi Stornello 5 speed by Don West, on Flickr

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Looks good Don, I like the idea of the stripes as the Italian flag. If you do it maybe try and make the angle of the stripes the same as the angle of the cylinder head and frame front down tube? Just a thought, maybe mock it up with strips of coloured paper first before committing to paint?

+1 for Filthy Dirty doing the paint. Had my BSA done there and they do a good job.

Just used the Deox-C on the inside of the petrol tank today and it does a great job, I am a fan! The locks have come back from the locksmith but one is still seized, so it will go back. He said that one of the springs was broken and some of the pins worn, so in stead of using both side of the lock he has used the best of the parts on one side each. I will have to make they are handed because if the lock is in the position without the pins and springs it can be opened with a screwdriver. So as long as they are handed I can mount them so that they will need a key when locked. Watch this space.

The De-Ox is best left in the tank for a good few days to fully do its magic. It is good stuff, it certainly cleaned mine out well.
Can you identify the lock to determine whar else it was used on, something like a Fiat glove box or similar. Do you have a part number for the lock? Try Googling Guzzi followed by the part number. I was looking for an air filter for one of my Stornellos the other day, did a quick Google search and found out it is the same as used in a a Fiat 126 so got one off eBay for a tenner in this country rather than having to go to Teo Lamers.
Is this the lock? Avaialable from Gutsibits £18.50.

There are no numbers or any other identifying marks on the locks at all.

As viewed from the outside showing the key slot

As viewed from the back with the latch arm removed

With the latch arm fitted. The part that looks like a V8 engine houses the two sets of springs and plungers that move when the key is inserted.

There is a small flat plate that slides off to release the springs and plungers. There are two sets so that the locks do not have to be handed. My locksmith has taken one set out which is ok as it means that in the locked position it needs the key to unlock it, but in the open position the lock can be turned back to the locked position with a screwdriver (or the key). I need to have at least this on both locks and for them to be handed. One of the locks (still with 2 sets of plungers) is a bit stiff and I’m going to ask my friendly locksmith to have another go at it. So fingers crossed.

Strange that yours has locks like that. Google search for the part number 12782200 & 14782200 all points to a simple cam lock. I assume you have looked into making a pair of them fit and lock.

Thanks Don, I think what you have found is for the earlier V7s. I am still trying to get the old ones to work. They are nearly there but I suspect they will have to go back to the locksmith. I am not going to spend another afternoon on my hands and knees looking for springs and plungers!

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many thanks Don for looking into this.

The lock set on the 750S parts list is not individually numbered but appears to be included with the tool box. But looking at the 850T parts list the part numbers for the locks are 14 78 22 00 and 12 78 22 00, these match the numbers you have found. These locks are identical so I had assumed that the different parts numbers refer to either the locks, the keys or the retaining ring on the inside of the toolbox door. They are both described in the English translation as “Lock set” however in the original Italian the first is “Gruppo serrat. per cass.” (assuming that cass. is short for cassetta) and the second is described as “Gruppo serrature”. The first translates as “Lock group for box” and the second as just “Lock group” I now realise that the locks are the same and not handed so the different part number is probably just a result of the Guzzi factory wanting to give everything a unique part number.

I agree that Gutsibits show the cam locks that you have posted as parts for 750S and 850T but I think these are not original equipment. They maybe my last resort if I cannot fix the ones I have!

I have found one on eBay https://www.ebay.co.uk/itm/324237321319 photo 5 shows exactly what I want but all the other photos show the lock barrel concentric and not offset. At that price I should not be so fussy!

Hi Chris
The parts book for the 750S suggests the lock set is 14782200, part 83 in the link below. The two references I mentioned previously was for the 850T.
I guess it makes sense that they are sold as pairs so the keys are the same.

Basic cabinet cam locks are cheap and plentiful

Thanks again Don :smiley:

My friendly locksmith has still not been able to free the locks up properly so I will probably buy new locks, trouble is most cam locks I can find are either zinc plated or from China. The ones on Gutzibits website are similar so I may go down that route.