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Evening All

“I stuck the below on a thread last week, maybe I should’ve created a separate thread so here goes..

With regard to converting my 1979/80 Strada to 520 (which I’d like to do), what’s the codes for those sprockets and length of the 520 chain please? It seems the 530 chain is 96 links and Tom’s identified the MuZ 660 JTR 18-39 tooth so I think this sprocket along with a 520 x 96 o ring-if correct-just leaves the front sprocket to establish?

Sorry to maybe be asking something that already has an answer, if so please direct me to that page! Thank you!”

I’m in the trade so can get stuff reasonably well, I just think whilst the 530 set up was fine in the day, I’m sure it would benefit from a smaller, lighter chain. TIA

I converted from 530 to 520 on my Sport about ten years ago.
The front sprocket is a 14 tooth one. Mdina Italia are showing zero units currently.
https://www.mdinaitalia.co.uk/M190123.html .
I seem to think its a 96 link chain, but they come longer than this e.g. 110 links so just don't cut it too short, something I did recently on another bike.
John

Most kind Sir, if I can find the number for the front sprocket (understandably Mdina don’t want to show it) I’ve cracked it, failing that I’m sure I’ll get the measurements. The centre isn’t the most common of cutouts!

Hi,

The sprocket you need is for the Dart. They came as standard with a 520 chain. Unfortunately I haven't got a Dart parts list, but someone on here must have.
Concur other comments, a worthwhile swap - it means you can run an o-ring chain and then be able to do a 'Euro-Tour' without chain adjustment!

Regards,
George

Nice one George, can you remember how many teeth front (and rear) for the Dart? I don’t know what sort of choice I’ll have-I suspect not much-but I’d prefer longer gearing over acceleration, be keen to know how the Dart was geared compared to the earlier stuff

Mdina have the front 520 sprockets for a 350 in stock.

Part number 19.01.38 (or M190138) I think.

14 tooth front sprocket

Dart was geared pretty much the same as earlier 350- 38 or 39 rear sprocket seems normal.

I’m not aware of any other bikes using the same front sprocket, and to be honest it’s good to support our Morini parts suppliers so suggest you get the front from Mdina. To be honest I’d have bought the rear from Mdina too except they didn’t have any at the time.

And just for completeness incase anyone misunderstands this thread in the future- the rear sprocket on a dart is completely different. But the front can be used with a suitable 520 rear sprocket on an earlier 350.

Hi again.
I would stick to 14 front 38 rear if I were you. The 350 isn't exactly a powerhouse, and 6th is a good cruising ratio. 6000rpm = 80mph ono, giving a good balance of smooth running, good economy and still have enough omph for (modest) roll on acceleration. Much taller (eg 37T) rear, let alone a 15T front (if there is such a thing in 520 size) I feel may dull things too much, but others may say differently. As with so much about the 3 1/2, I would say Morini got the gearing pretty much spot on as standard.

Regards, George

Thank you for all the info everyone, I can get to work on this in the winter

I was fairly sure my K1 has a front sprocket with two flats rather than splines. It has not been off for 6 years though.Thats all I know. Sorry if any erroneous info
John

350 has flats, the 500s have splines, and the 'nose'/boss which looks like it ought to space the sprocket out from the crankcase, actually goes outboard, not inboard towards the cases