I'm one of those blokes who live by the credo "the slower you are the faster your bike must be". I hotted nearly every bike I've owned but I kept my Maicos surprisingly stock in comparison. To use my MC350 square barrel as an example, here's the basics from 40 years of ownereship.
*Replace brittle fibreglass fenders with aftermarket plastic items. (
then Pacifico now DC opaque)*Replace tank with alloy version. (
then '74 Lyta Vic Eastwood....now 77 AW or '74 narrow coffin)*Replace shocks (
then Koni steel and then finned alloy....now Works Performance and currently YSS) *Replace full width front brake (
then conical DT2MX Yamaha.....now 77AW conical Maico)*Replace original bolt on cross bar handlebars (then and now Inter-Am solid alloy)
*Replace slippery tubular pegs (
hen home made serrated mild steel...now Wheelsmith steel)
*Replace Carburettor (
then 34mm Mikuni ....now 38mm Bing from a Husky)*Replace stock points ignition (
then stock points....now PVL)
*Replace original big clutch with later small dia version (
then, '74 Maico 440 small dia...today '81 Maico forged basket and Barnett plates.)*Replaced stock pipe numerous times with '74 440 Wheelsmith pipe and the current Peter Reynolds fatty being the only pipes that made any noticable difference.
Back in 1973 or so I had Gary Treadwell blueprint and champfer the ports without modifying them very much. Later on in the 90's I had the head machined to replicate the Magnum era "square wall" combustion chamber but the perforrmance difference was minimal. I used Castrol TTS oil for 20 years when on Petrol and Catrol R when on methanol and only had one engine failure, in 1991 when the inlet manifold rubber came adrift and it sucked in a whole bunch of Dargle sand. I now use Motorex.
I have a few little personal mods like Wheelsmith fork dampers, Vintage Iron springs, Wheelsmith air caps, Wheelsmith brake stay/chain guide and brake pedal, Webco gas cap, alloy airbox, Twin-Air filter, alloy Boyd and Stellings swingarm and later alloy back hub but stuff is just bling that has little bearing on the bikes performance. They're just the folly of an old Maico tragic keeping his pride and joy looking pretty.