1964 Stornello 125 bottom end kit

Hi - am trying to source a bottom end kit; would be most grateful if anyone can point me in the right direction. Thanks. Terry

What do you mean by a bottom end kit? Gaskets, bearings, rubber seals?

Hi Don - thanks for your response; yes its gaskets, bearings and rubber seals. Cheers Terry

Hi Terry
Good to hear from another Stornello owner.
The bearings are standard off the shelf from any decent bearing supplier. Just measure your old ones and you should be able to come up with a match. Some are not cheap as many of them are quite narrow, 9 to 15mm. This is my list from when I rebuilt my engine back in 2013.

  1. Roller bearing, loose inner race on the crank. 20 x 52 x 15. Reference NU304??? Ref ECP or ETVP ??
  2. Ball race. with some metal shield. 20 x 52 x 15 Ref 6304 About £4-00 Simply Bearings
  3. Ball race, unshielded 25 x 52 x 9 Ref 98205. Approx £65.00 on Simply Bearings Ouch
  4. Ball race, unshielded 20 x 52 x 10 Ref 98304 Approx £26.50 on Simply Bearings
  5. Ball race, unshielded 15 x 35 x 11 Ref 6202 £2-00.

As for gaskets, I tend to make my own. The left outer cover isn’t critical about thickness ( I use some quite thick gasket paper) but the crankcase gasket does need to be very thin paper or it will mess up the shimming of the crank and gearbox. You can buy gasket sets, the last ones I bought from ebay in Italy where hopeless, nothing fitted.
There aren’t many rubber seals in the bottom end, just the kickstart seal from memory. You will need new push rod tube seals and they are available from Italy. They come in an engine seal kit. Make sure you get one for the 4 gear model as the later 5 speed bikes are different.
I have never used them, but have heard good reviews for Guzzi Retro for supply of parts as a one stop shop that sells all. I expect his gaskets would be of decent quality.

If rebuilding the bottom end, it is important that the gear selector mechanism is assembled correctly, you will need this document to get it right (It is even printed in English)

I can supply pdf’s of other documents (workshop manual, parts books etc) if you need, but they are all in Italian.
Be aware there are two versions of the Stornello from 1964, the Sport and the Turismo and there are a few differences, mainy in the top end of the engine.
This is my Turismo Note a diferent rocker cover and fixed front mudguard.
Naseby by Don West, on Flickr

1 Like

Hi Terry

Stein-dinse have 3 pages of Stornello 125 parts covering most of what you asked for.

Regards, Nik

Thank you so much for your great response - much appreciated.
I have worked on many cars over the years but as my space is now limited I have acquired my first motorbike to renovate. Its great fun but without a trusty Haines manual its proving quite a challenge! Consequently the service sheet is very useful :smile:. I have managed to download manuals and parts lists but as you say - all in Italian.
I’m not sure if mine is a sport or a turismo - do you know how to tell them apart? Cheers

Thanks Nik - I’ll have a look. Regards Terry

Hi Terry
The Stornello is a fairly simple machine to work on. I have rebuilt a few so feel free to ask any questions. Have you got a photo of yours to show?
The main difference between the Sport and the Turismo is the top end of the engine. The photo above is a Turismo. This is a Sport model, note the different rocker cover on the top of the engine.
30 Oct 23 (2) by Don West, on Flickr

Hi Terry, Don has given some great advice, as always. He is a Stornello Guru, for sure. I use GuzziRetro for my spare parts. They might not be the cheapest but they do provide a very good service. I have bought both the seal kit and gasket set for my Stornello restoration from them. the Gaskets are made in Italy by Athena using British Flexoid papers. Hope this helps, Phil

Thanks Phil - useful info.

Hi Don - many thanks for your response and for your kind offer of help. Given my inexperience here I feel certain to be back in touch!

Just about to split the crankcase - pretty sure the big end bearing has gone! Cheers and thanks again. Terry

1 Like

Hi Terry That looks tidy. I would say it is around 1968ish. Interesting that it has alloy rims as I thought by that time they were using chromed steel. I would say it started off as a Sport America, possibly the scrambler version.
As a quick check of the state of the big end, remove the right cover, put it at top dead centre and rock the flywheel back and forth to see if you can detect any movement. If you do decide it needs a strip and rebuild, the big end is a roller assembly that comes as a complete kit usually’ like this…

But don’t buy that one as the crank pin looks pretty rusty. Be aware, there are two different gudgeon pin sizes used, 14m and 15mm so measure your piston before ordering a crank set.

Thanks Don - very useful information. Crankshaft wont turn at all! Hoping to split the crankcase tomorrow to see whats going on. Cheers

Hi Terry, I thought that photo looked familiar, you posted about the bike in the clubs Facebook group back in November. You had it running at that point. It’s very strange that it seems to have locked up now. It will be interesting to see what you discover. I doubt if the crank has siezed.

Hi Don - yes that was me! I did get it running back then. Strangely it locked up afterwards in the act of kick starting!
Split the crank case today - alas it is the big end that has completely seized.

So am on the search for a 15mmm kit; so far with no luck- have asked retro motor guzzi if they have one.
There is hardly any play in all the other bearings so am tempted leave alone or perhaps this is a false economy?
I understand from Ian Faloons Moto Guzzi book that Moto Guzzi provided some 125 American Sports to the Italian Police in 1966. Given mine is blue and most seem to be red I’m guessing this is an ex Italian police bike.
Kind regards

I did wonder if it was an ex polizia bike.
That’s most strange that it has siezed. I would guess the cage holding the rollers has broken up and the rollers have jammed the crank.
I am shocked by the prices people are asking for these on eBay.it.

I bought one for mine back in 2019 for 65 euros plus postage as I know the one in the bike is worn.
I bought mine from this guy , it might be worthwhile sending him a message to see if he has one for you (15mm spinotto)

I expect you have been studying this, from the parts book

Here is one that looks right.

Hi Don - thanks again for your help. Have just ordered it. Think its well beyond me and my meagre abilities and equipment to fit - I guess there must be companies out there that do this sort of stuff. Any pointers?

The flywheels will need to be separated and then pressed back together so yes it is an engineering job. Where abouts are you in the country?

Deep South - just outside Portsmouth