Suzuki 2 Strokes

Following advice from JWDFA on this site I successfully installed on my T350 a Tympanium reg/rect often used on old Triumphs and BSAs.
These cost about $60 US but recently having to source a new reg/rect for my Briggs and Stratton mower engine I came across these units advertised on EBay for around $20.
Considering the paltry alternator power generated by the T250/350 it may be these cheap units might suffice for the T's.
https://www.ebay.com.au/itm/38380737257 ... gIZufD_BwE

The battery voltage needs checking (engine running) with ignition and lights on to make sure it's actually charging in both switch positions. You need 12.8 volts minimum to actually charge the battery, whether the lights are on or off. Also make sure the thing gets some airflow as it'll get warm, possibly hot when in use.
AFAIK, the T350/T250s run 2 coils to the rectifier when 'just' ignition on, but with lights on extra coils are put into circuit from alternator to rectifier, so in effect, it self regulates same as the T200s I had. I just used one of these when I found a dud rectifier on a rebuild I did - ebay 124845173125 , rated at 15 amps, and it worked fine. More details here - viewtopic.php?f=20&t=13815&hilit=T200+charging

Triples are completely different as they have a 3 phase alternator and the regulator regulates current to the rotor.

I did the Tympanium reg/rec upgrade on my twins with great results. Recently I had to replace the reg/rec on my Kohler lawn tractor engine, I replaced it with one similar to the one you mentioned, and wondered the same, if it works on a lawn tractor, could it be a cheaper option for the twins?

Your $20, my £2. Mmmmmh....

The reason I use modern reg/rec is so I can use AGM batteries. I found myself replacing conventional batteries every 2 years or less, where AGM batteries last up to 4-5 years, The rectifier usually doesn't give me much trouble, but the regulator system does not give a very good regulation. the original regulator system on the twins, (if they even had any,other than battery) were not very accurate, voltage can go as high as 16-17 volts. The new reg/rec system does a much better job of keeping the voltage below 14.2 volts which is the highest AGM batteries can handle without cooking them dry, and preventing premature light bulb failure.