Hello!
I'd like to know if there is any problem in putting a 14 amp hour instead of the regular 12 amp hour in a Teneree 600 2VG 1990.
Thank you

Generally no. Whatever vehicle/engine.

Needs a bit longer to fully charge, and is possibly heavier. Do you need the extra capacity?

For electric start the CCA value is crucial (Cold Cranking Amps), which ist hoch much power is delivered to the starter. The more the better (starter will rev higher, resulting in easier start, and voltage will drop less). Which is why Lithium batteries are still perfectly fine having only a quarter of the original lead-acid Ah - they have a very high CCA rating.

The Ah value tells the total capacity of the battery - i.e. how LONG it will be able to power the starter. Which may be important if you are troubleshooting and have to start the engine multiple times without recharging the battery by driving. Or if you want to recharge your laptop overnight etc.

Andy