Kayo 140: A Review of its Shortcomings

In October, we purchased six Kayo 140 pit bikes over a period of time—five motocross models and one motard. As motocross enthusiasts, a test on the old motocross track couldn't wait. But first, a prelude. After acquiring the bikes and bringing them to the garage, we undertook a thorough inspection and checking of fastenings. Assembly at the warehouse varies with seller and factory worker moods in China. Tighten everything meticulously, especially the rear sprocket. Even secured by a lockplate, you’ll be surprised how much more the bolts can tighten once you remove the lock. This is crucial! I also highly recommend lubricating the cables, especially the clutch cable. This will eliminate unpleasant noises and significantly extend its lifespan.

Next, focus on handlebar attachment, which I'll explain later. Tighten the hex bolt fasteners forcefully! We idled the engines for a bit, then rode gently, not heavily burdening the motors. Not everyone maintained restraint, of course, but we did our best. After five hours, we replaced the oil correctly (Motul 7100). When draining old oil, remember to tilt the bike to ensure complete drainage.

1. Rear Shock Absorbers: As you might guess, it wasn't warm, and the mopeds sat freezing in the garage. We then discovered the rear shock absorbers weren't working! Disappointing indeed. Initially noticed by someone, then myself. We speculated the oil had frozen due to intense leaps or gas hadn't been sufficiently filled. Indeed, expelling some gas revealed minimal pressure. Air was added (ordinary compressor at 3-5 atm). It seemed to work but soon failed again. The symptoms—his return stroke hitting hard—suggested only the spring was functioning. The diagnosis: too viscous oil... not for winter use. A little riding heats the oil, normalizing function. Don't overstrain on cold days—you may ruin the shock.

   New! We resolved to tackle the issue. Fill the shock with 10 to 20 atmospheres. Tip-off about pumps for bicycle forks/shocks—a High Pressure Pump! It goes up to 20 atm. We pumped to 15 and celebrated. Even in the cold, it stabilizes—problem solved. We won’t change to less viscous oil yet.

2. Handlebar Integrity: Big jumps, unfortunate landings, and your handlebars spin in their mounts. Both unpleasant and unexpected. As earlier stated, tighten mounting clamps securely. Concisely: handlebars and mounts are subpar.

3. Lever Durability: Brake and clutch levers are terrible. Folding does nothing for durability. Levers snap, folding offers no protection. Sets cost 700 rubles, an expensive, repetitive replacement. Buy handlebar guards or loosen lever mounts—let the lever pivot rather than snap during falls. A standard trick.

4. Oil Cooler Hose Issues: Haven't found similar reports online, but it leaked. We hadn’t hit anything, no branches. The issue arose at the crimp where it joins the fitting. A defect? Perhaps badly done by a worker. The hose isn’t easily replaceable. Options: order, make one with clamps, or custom fabricate (high-pressure sleeves). An unwelcome failure.

5. Chain and Sprocket Wear: Chains stretch hugely... replacements loom. Buy quality brands. Rear sprockets, even with bolt lockplates, loosen. Use Loctite—and re-lock if possible.

6. Muffler Rattle: Muffler rattles for many. Particularly the mesh at the can's outlet. Annoying rattle source. I’ll describe a solution, though surely more exist.

   New! First, dismount the muffler. Drill out rivets and remove the cap. You'll see a large can-shaped ring, a large washer, then internals (packing and sieve-tube). From the factory, sieve-tube and rings are poorly welded. They separate within hours. Solution—weld anew, but I took another path. I discarded the washer. I found a 5 cm pipe to snugly fit inside the sieve-tube. Welded the found piece to the large can-shaped ring. The cap has predefined bolt features. Drill holes for M6 bolts. Drill, tap the ring, and weld on nuts. Now, the previous rattle source secures soundly. Attach bolts, replace rivets—rejoice in silence!

7. Bearing Seizure: One of us, fond of sloshing through mud, had rear wheel bearings seize. Yes, they're sealed, but dirt in conjunction with Chinese quality wore them down... they spun stiffly, binding. Replaced with new ones sourced from an auto parts store. Lada fits somehow.

8. Peg Issues: Peg springs and pegs easily dislodge. Ends are weak—re-bend with pliers.

Whew, that’s all. How much or little? Each judges for themselves. We approached it from a usage perspective—riding on a motocross track. Worth noting, they jump well, the suspension absorbs hits. Of course, stiffness is adjustable, depending on one's high-flying prowess. If Chinese manufacturers equipped bikes with quality parts (bars, chains, suspensions), prices might double. That’s how a standard and race-ready pit bike differ in price/quality. For now, we'll hold off on replacements and continue monitoring our test subjects. We'll see how it goes.

Many words, but I hope our experience proves beneficial. Good luck to all!