flywheel compatability?

[Andie]

I'm after a replacement flywheel: the fitted one is a Ducati 31.43.44 - brass with two windows.
The stator is 4 pole - although the British Lambretta Archive states:

"4 Pole to 6 Pole: On 26.9.1962 Innocenti made a change from 4 pole to 6 pole magneto's the machines where this change started are as follows:

Li 125 (Series 3) from frame number 036626 onwards
Li 150 (Series 3) from frame number 631475 onwards
TV 175 (Series 3) from frame number 507945 onwards" - http://www.britishlambrettaarchive.co.uk/info-corner-series-3-1.html

Mine is a 601xxx 125 frame - '1963: 051,478 - 101,942' (engine is only 300 numbers away) which is a bit trainspottery...

Anyway - are S3 flywheels interchangeable? - could I use a later 3 windowed version, designed for 6 pole points, for example? or will the magnets be 'wrong'?

*edit* aside from looking like it's been botched with a screwdriver, which is probably has, is one missing fin going to inhibit flywheel balance and cooling that much?*/edit*

Andrew

[Adam_Winstone]

You can change Italian 4-pole stator and flywheel for the 6-pole Italian stator and flywheel (lots of different of later types though, incl. brass + alloy, alloy, Spanish, API Indian), some of which will work OK. None of the flywheels with the later GP boss/taper will fit earlier cranks.

Adam

[Andie]

Thanks Adam.

So a 4 pole stator plate needs a 4 pole flywheel. That does makes sense.
I am keeping it 4 pole as its a conservation for the moment, and a bit unusual.

[Adam_Winstone]

^... correct.

[Adam_Winstone]

4-poles can work well, as they have for me in the past, but I've also been left stranded after one failed on me. I then saw a Brit nearly stack his bike when it locked up on him at a Euro Lambretta, turning out that he suffered the same 4-pole failure that mine had.

My reason for saying this is that most manufacturers change things for good reason [ mechanical benefit or financial benefit to them ] so watch out for 'staying original' if it sticks with old problems!

FYI - The problem of the 2 examples above is where the alloy fan comes loose on the brass centre and allows the rolled pins that go through the side and into both the alloy body and brass centre to come loose and machine the mag housing every time the flywheel rotates. This problem is so common that the 'late great' Dave Webster even joked about it in his tuning manual, saying that these are the easiest assemblies to lighten... if they haven't already do so themselves! (or something like that)

If you are going to upgrade then it is worth skipping the alloy + brass early SIII assemblies and go straight to the later all alloy flywheel and stator. Stick with the Ducati assemblies though as many of the Italian home markets were fitted with other brands, which have issues of their own.

Adam

[Andie]

Thank you for the reply Adam.

Once more lots to think about...

[Andie]

Have decided to update to SIL 12v Electronic Ignition - will order after checking whether to keep the Li crank or replace it with a new GP one...
Thanks for the advice!

Andrew

[Adam_Winstone]

If you are going to increase capacity or fit a tuned kit then upgrading to a GP crank is worthwhile, if not a necessity, to avoid crank taper issues, however, the Li / SX / TV type cranks are fine in most mild tune motors up to 175cc. If you do need to replace a worn crank then it is always worth fitting a GP crank, although I'd not go for a standard SIL crank unless you update the main conrod bearing or opt for a better quality crank.

Adam

[Andie]

Thanks Adam. I've passed the engine onto a professional for various bits of work that I cannot undertake and he's gonna look at the crank before I order the 12v

however, I was looking at the Gori Replica 175 iron barrel, but may go for the Mugello 186 as its seemingly tried and tested, in which case a GP crank is on the cards.

Andrew

[maz]

I'd go for the Mugello 186 every time !

[Andie]

Thanks Maz.

Kit choice opens up another barrel of fish completely - originally I just wanted the 125 to 'conserve' and ride - obviously a 50 year old machine needs some work, which I am trying not to let snowball into a total avalanche! However a 125 is going to be fine in town, but I'm more likely to be taking leisure rides across the Dales, so an upgrade is sensible, if not essential. Also its on 3rd oversized piston now, apparently.

The stator and flywheel need replacing, and the gearchange mechanism - so why not replace the crank for a GP while it's open... However a tuned big kit is going to mean a new gearing ratio, improved brakes, carb etc and I'm on a budget (Ha! - it's a payday to payday restoration so taking some time).

Mugello or Immola win on recommendations but the Gori Replica 175 looks interesting as it's just a 'bigger' iron and cast in Italy - Rimini say it's a rebuild of the TV 175 (so not an overbored 150) I need to check the con-rod length but they say it's a regular 'bolt-on' for a 125 Etc. Not super fast, but should take it to a 50 mph cruise speed. I'd be interested if any other riders have fitted one. probably another thread.

thanks again!

Andrew

[maz]

I live in Wharfedale and ride into Leeds at least once a week ( Thursday nights / club night's ) plus I do a lot of riding in the dales.............. I ride and look after 2 scoots with mugello 186 top ends on ( one my son rides ) and I can tell you they are the best rides of anything I have / had. Of course it all depends on where you are going to ride your scoot............ longer, dual carriage way / motorway rides IMHO you need TS1, RB, Imola etc. , but if your doing local B road stuff then Mugello 186 is responsive, fast enough for you to enjoy the ride etc.

The Mugello 186 works equally well with a combo of 25ml Jetex / 42ml Clubman or 30ml Delorto / 48ml Clubman the later being particularly interesting around town with a 125 gearbox.

[Andie]

Thanks Maz.

Always good to get a recommendation - It'd just be another month's budget outlay to get the 186. I dn't think I'm be driving it til after the snow now anyway...
But yeah, it'll be B roads, of which we have *edit* some of */edit*the best in Yorkshire and town. defo an option.

Thanks
Andrew