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Time for some new ones for my Sport.
What chain is standard ? I see front sprockets at Mdina listed as 520 and 530. Im not sure what to get.
Cheers.

I use 520 x ring . Bit of overkill I expect. 530 will fit just but only a “normal” chain ( ie not o or x ring) It’s tge engine sprocket/crankcase clearance that is the issue.
Std is 96 links.

Is 520 the stock size ? Im not after x or o ring.

No, standard size is 530. This is also called 50 by some makers and 5/8x3/8" on old money.
520 is the same pitch but narrower so won't fit over standard sprockets. The advantages with 520 include being lighter, narrower so it's easier to fit O or X ring chains and the breaking strain spec is usually higher too.

The Morini is not exactly blessed with ponies, not exactly an Italian Stallion.

520 size and a good quality chain. No O or X or the latest thing for me.

The darts used 520 chains as standard.

On my earlier 350s I have moved to 520 chains, as said above, stronger, lighter and narrower. For our bikes no downside in my opinion.

You can also get an off the shelf rear sprocket cheaply and widely available (JTR18 from MuZ 660 scorpion) in 520 width that fits the 5 bolt sprocket carrier of the sport.

Front sprocket is unique to Morini but Mdina stock all types.

I’ve been using DID 520 ERVT x ring chains as a reasonable compromise between weight, friction and longevity. No problems, even on the 501 dart which has quite a long chain and more power than most other aircooled Morini.

I agrege, the 520 DID chains are my prefered ones as well also for 501

I converted to 520 a couple of years ago, just looks right, lighter, more modern set up. I had no problem getting the correct front but couldn’t get the 38 rear, eventually sourcing a 39 from Spain. Bit peppier acceleration but I wonder if the 38 is easier to find now?

I use the 39 teeth with 501 motor

funsize wrote: ↑03 Aug 2025 17:37 I converted to 520 a couple of years ago, just looks right, lighter, more modern set up. I had no problem getting the correct front but couldn’t get the 38 rear, eventually sourcing a 39 from Spain. Bit peppier acceleration but I wonder if the 38 is easier to find now?

This could be a good option to give a bit more mid range ommph !
Mdina stock 38, but I dont see 39. Where in Spain did you get your 39 ?

From Dieter Hoffmann/ Germany.
He also could obbtain me a 520, 39 teeth for a 6hole for spoke Stada wheel

Mdina stock 38, but I dont see 39. Where in Spain did you get your 39 ?

The JT sprockets one I mentioned is available in a 39 tooth for the 5 bolt pattern. It’s what I’m running on my 350 sport with 110/90/18 Avon roadrider on the rear the ratio suits my riding style well.

If you search on eBay “muz 660 jtr18 39” you’ll find plenty of options.

I hadn’t found a 520 option for the 6 bolt hub so Norbert’s information about Dieter supplying them is most helpful

This 6 hole hubs needs to drill the holes 1 mm wider if I remember it well.

rossguzzi wrote: ↑03 Aug 2025 23:59

funsize wrote: ↑03 Aug 2025 17:37 I converted to 520 a couple of years ago, just looks right, lighter, more modern set up. I had no problem getting the correct front but couldn’t get the 38 rear, eventually sourcing a 39 from Spain. Bit peppier acceleration but I wonder if the 38 is easier to find now?

This could be a good option to give a bit more mid range ommph !
Mdina stock 38, but I dont see 39. Where in Spain did you get your 39 ?

Errr, can’t remember now but I will certainly try to dig out the paperwork, I’ll have it somewhere! Conversely, if the 38 is easily obtainable for a 1980 MK5 would someone point me, like to have both if possible

norbert wrote: ↑05 Aug 2025 00:42 This 6 hole hubs needs to drill the holes 1 mm wider if I remember it well.

Can you explain this a little more please ? Not sure what you mean.
Cheers.