Ktm Sx 125

I raced one of these through '96 and the power delivery was nothing short of savage once you hit that 10,500 rpm wall — below it, you're pushing a shopping trolley; above it, you're holding on for your life. The steel frame flexes noticeably in fast ruts compared to what the Japanese were doing, but it communicates the front wheel beautifully, which I actually came to appreciate. The WP suspension was basic even by mid-90s standards — underdamped on square-edged hits and required constant revalving if you rode anything harder than a groomed track. Reliability was genuinely good for a screaming two-stroke race bike, but the power valve needed cleaning every few hours or the bottom end went soggy and you'd be wondering if the bike was sick or just protesting your maintenance schedule.

The revised chassis geometry genuinely changed how this bike corners — it tracks cleaner through rutted turns than the Gen 1 ever did, and the updated suspension linkage soaked up square-edged hits that used to rattle your fillings loose. The power delivery improvement is real too: less of that brutal on/off hit at 9,500 rpm, more of a usable spread that lets you actually drive out of corners instead of just hanging on. That said, 985mm of seat height means shorter riders are constantly fighting it on slow technical sections, and the new bodywork, while sharper looking, cracked around the subframe bolts if you weren't careful with torque specs. This is still a machine that demands you ride it with commitment — back off mentally and it punishes you immediately.

The Gen 3 chassis was a genuine step forward — the chromoly frame stopped the flex-and-wander I'd cursed on the older bike, and the revised WP forks actually held their tune through a full moto rather than diving into mush by lap eight. That engine is still a narrow, demanding powerband that lives above 8,500 rpm; get lazy with the clutch and it bogs, stalls, and embarrasses you in corners where a CR125 would have already exited. Ergonomics improved enough that I stopped fighting the bars on long practice days, but the seat foam remains a cruel joke by hour two. If you can keep it singing, the power delivery through the top end is explosive and precise — this thing pulls hard enough that 88 kg feels genuinely fast against 250 four-strokes on tight tracks.

The Gen 4 SX 125 is genuinely violent in the best possible way — that revised cylinder and head pushed the powerband into territory where you're either fully committed or getting left behind. I ran one through a full MX season and the WP forks were a revelation over the previous gen, holding up under hard braking into berms without the wallowing I'd felt before. The frame revision tightened steering response enough that you notice it immediately on tight, technical tracks, though it also amplifies every mistake at speed. Jetting still needs attention out of the box in cold weather, and the thing will detonate your confidence if you let the revs drop — but if you're willing to keep it screaming above 9,000 rpm, nothing in the 125 class touched it.

That new frame transformed everything — the Gen 4 always felt a touch nervous mid-corner, but this chassis plants the front wheel with real confidence on hard-pack and lets you hang it out on loose without the bike trying to swap ends on you. The revised engine internals tightened up the powerband noticeably; it still snaps onto the pipe like someone threw a switch around 8,500 rpm, but the hit feels more controllable, less like a caught-out moment. Braking got genuinely better — the updated front setup has actual feel instead of the binary on/off of previous gens, which matters when you're scrubbing speed into a rutted downhill. Honest weakness: that 995mm seat height is brutal for smaller riders, and the transmission is still a bit clunky shifting down under hard braking — something KTM never fully sorted this generation.