"S" stamp on 1981 Sport engine?

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Marco64
Posts: 16
Joined: 08 Mar 2016 21:25
Location: London

"S" stamp on 1981 Sport engine?

Post by Marco64 »

'Morning all,
Without you all starting to call my Morini Frankenstain (she's sensitive!) can tou help me please? I bought this 81 bike in pristine condition for peanuts in Italy. Everything looks great. I have finished doing everything up (brakes electrics etc) leaving the engine last.

I am actually not worried if it is a sport engine or not (this bike is for my girlfriend and she is throttle-happy so if it's a little slower...great! I just want to service it correctly (carbs, valves etc).

Firstly, there is no oil pressure switch but the loom runs along side the chassis to a spade connector near where the oil switch could have been. To me that's a tell-tale engine swap- is that so or could the factory have wired the harness for an oil switch then fitted an engine without?

Secondly, I cannot find an "S" on the engine, but somewhere I read that from about 1980 the difference of a few ponies was deleted and there is no S for a reason. Id that true?

If the above is inconclusive, what to do? Measure pistons? Check engine number? Dismantle and see camshaft lobes angle?
Thanking you in advance!
I am catching morini fever... must buy early model before they appear in jewerly shops!
mgelder
Posts: 136
Joined: 18 Jan 2011 14:36
Location: Cambridge

Re: "S" stamp on 1981 Sport engine?

Post by mgelder »

My 82-ish 350K Sport has an S stamped on the crankcases, and an oil pressure switch.
Morini stuff on RealClassic.co.uk: http://www.realclassic.co.uk/profiles.html#morini
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Ming
Posts: 798
Joined: 01 Aug 2014 16:32
Location: France
Location: Central France

Re: "S" stamp on 1981 Sport engine?

Post by Ming »

Marco64 wrote:...I am actually not worried if it is a sport engine or not (this bike is for my girlfriend and she is throttle-happy so if it's a little slower...great! I just want to service it correctly (carbs, valves etc).
I think that is the right attitude to take - sourcing a sport engine if you don't have one is already like searching for a Faberge egg!
There is plenty of info available for servicing (look for Paul Compton on Youtube), I can mail you some also.
Personally, I can live without an oil pressure switch - check the dipstick and listen for new rattles.
Above all, enjoy it.
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72degrees
Posts: 1549
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: "S" stamp on 1981 Sport engine?

Post by 72degrees »

Ming wrote:
Marco64 wrote:...I am actually not worried if it is a sport engine or not (this bike is for my girlfriend and she is throttle-happy so if it's a little slower...great! I just want to service it correctly (carbs, valves etc).
I think that is the right attitude to take - sourcing a sport engine if you don't have one is already like searching for a Faberge egg!
There is plenty of info available for servicing (look for Paul Compton on Youtube), I can mail you some also.
Personally, I can live without an oil pressure switch - check the dipstick and listen for new rattles.
Above all, enjoy it.
Indeed. I suspect the only difference in servicing a Sport (higher CR and lumpier cam) rather than a Strada (before they became much the same) is the carburettor jetting. That is not an exact science, so if not sure what state of 'tune', it becomes a matter of 'seat of the pants' testing, with the odd plug chop if worried about wide open throttle conditions.
Marco64
Posts: 16
Joined: 08 Mar 2016 21:25
Location: London

Re: "S" stamp on 1981 Sport engine?

Post by Marco64 »

Thanks Guys, much appreciated!
I'll let you know how I get on... :-)
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