Solid engine, iffy brakes
Despite its huge output the liquid-cooled, dohc, 16-valve,v-four is generally solid (if not bulletproof) – although there have been some problems recorded concerning its small-end bearings.to check, start it up and, when in first or second gear under acceleration, release the throttle and listen for a slight rattle.
The standard brakes are distinctly underpowered, particularly on the pre-’92 models. Sensible improvements include using braided steel brake lines and EBC double HH or Ferodo pads. More involved and expensive improvements include switching calipers, with R1 ‘blue-spots’ and Harrison Billet being popular.
Very early (pre-1987) US examples were recalled to have a gearbox modification, as these models developed a fault where the bike could jump out of second gear when under heavy acceleration. All models since then had the stronger gearbox, although it’s not unheard of for the same fault to develop under repeated hard use.
The officially-imported UK bikes between 1991 and ’96 came in French specification, meaning that they were restricted to 100bhp by not having thev-boost system fitted. Having it fitted retrospectively is hugely expensive.you’re best off getting either a post-’96 machine or an import.
Suspension and handling has never been thev-max’s strong suit but it can still be improved. On pre-’93 examples with the 40mm forks, stiffer springs are a straight swap
Be sure about what you’re buying. Pre-’93 bikes have weedy two-piston calipers while early official European imports (1991-’96) were restricted to 100bhp – quite a difference from US bikes which have a claimed 142bhp (at the crank). Even Japanese market machines were restricted via the speedo (to 113mph) and are tricky to derestrict.
As with most Japanese machines of the era, thev-max’s regulator/rectifier often packs up