Chabging from Saprisa to Bosch

Gambalunga April/May 2012 proposes that the weak Saprisa alternator should be changed out for the better Bosch unit

I have a 1980 LM2 and one of the recommeded improvements to charging is to swap the original unit for the better Saprisa unit from the slightly later 1000cc engines.

Another alternative might be to look at one of the Alternator upgrades such as shown here -
But this solution is outstandingly expensive.

However if any of you guys plan to follow the solution whereby you strip out your Saprisa unit and replace it then please let me know. I may well be in the market for your scrap (but working) Saprisa alternator and associated regulator.


I feel there is nothing wrong with the Bosch unit.
The police regulator brings in full charging volts at about 1500 rpm and is worth it if you run at low revs.
If you have a mechanical regulator you can tweak it yourself but you do need to know what you are doing.
I believe the Saprisa unit in total is slightly lighter, otherwise cannot see any reason to fit it.
If you have poor charging check your connections and replace all the female spades, then check your earths.

Well the Bosch system on the V1000 is now 36 ish yrs old working and never a problem, the Ducati sys on the V11 has needed a replacement reg/rect and a new fuse block as due to overcharging it melted the 30A fuse holder … I will stick with Bosch Thankyewverrymuch , I did get a Police stator yrs ago and the reg too so I have ample sparks to run all the additional marker lights and spots …never been a problem …but yes like Ian I do keep the contacts clean , change the spade terminals and generally check it is all good

I can see no reason to change a Bosch unit for a Saprisa, but then neither can I see the point of changing the other way.
There are two regulators for the Saprisa, early and late, the latter being rather larger, but does give better charging.
The problem which the Sap[risa suffers from is idiot owners pulling the stator off and leaving the rotor on the crankshaft, or at least seperating the two. This has a serious detramental effect on the magnets in the rotor which in turn will reduce the output very considerably. If you ever remove a part always keep the rotor safely inside the stator. This advice goes for any permanent magnet alternator, the later Ducati one too.
Given that the Ducati one is higher output than the Saprisa, changing to that would be more simple as I believe adapters to fit on the crankshaft are available.

In the diagram in the gambalunga article are the rectifier and regulator labled correctly? I thought the regulator was the one shown on the right and the rectifier on the left connected to the alternator via the three yellow (or white as in the article) wires. Please correct me if I am wrong.

You are certainly not wrong Chris.

Speaking to these guys at The Stafford Show I think IF I had issues with charging on a Guzzi I would seriously think of their system brushless seems a good idea