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I am rebuilding a Ducati 500 Desmo Mototrans and I will need a set of pistons in first or second overside (78,4 or 78,6 mm)

Anyone got a good recommendation??

Gonzalo

This a good question !
I begin to know about all the web sites and shops who sell NOS parts for these motorbikes and I have never found any piston, standard or oversize for the 500 cc.
I know that Giovanni Gentile (Classic Italian Bikes) have oversize pistons for the 350 engine, that is all.
(but you can find new liners in two different adresses)
So, if somobody knows where there is a chance to get that, thanks very much.
There is also the possibility that some workshop manufactures new pistons like Aprotec (they have a web site) in France, but it is very expensive.
Try there as well, they make pistons on order, any size, if you send an old one for copy:
http://www.roadandrace.com.au/pistons.htm
Nevertheless, on these engines the pistons and liners are quite "long lasting" (strong) and of course it is easyer to get a good second hand set.
That is what I have done on my parallel with new piston rings and it is just fine.
But there is a better and cheaper solution:
-send your pistons to a goog workshop to make them renewed, if necessary the external diameter will be reduced one or two tens of mm.
-buy a pair of new liners and pistons rings from Classic Italian Bikes or Desmo Shop (Germany). This new liners are 77 mm diameter so you can make them rebored to the exact size according to your renewed pistons.
Be carefull at the end with the piston rings diametral gap, if necessary you can adjust that with a file.

Enjoy yourself.
Gé

Thank you for your answer... and congratulations for your web

I think:

it would be possible to rebore to 80 mm with the same liners?. This would make possible to mount the 750 pistons

Ok, ok, it´s imposible. The pin isn´t the same

Hello !
The maxi you can rebore this liners is 79 mm, if more they become too thin an it is dangerous.
And if you try different pistons you will have problems with the pin diameter and it's position (too high or too low) in the piston.
So the best is to forget that.
I have seen your pictures of cylinder head in "la maneta", beautyfull !
Anyway, if your pistons and liners are within the tolerances, just fit new rings after deglazing the bores and that's it .
Have food fun !
Gé

If anyone is interested i have one 78 mm piston ( no rings no wristpin and no circlips ) and 2 sets of 78.4 mm piston rings
these items are new and i would like to get 50 euro for the piston and 40 euro for the 2 sets of rings
items are located in the Netherlands ( very close to Giovanni )


Eldert

Hello.

I know a guy who has rebored to 80 mm an fit 600 pantah pistons.
I don't know about the pin diam and piston height but his bike runs like hell in racing.
The cylinder sleeves must be very thin, but it works...

Gé