Kawasaki Kx125
KAWASAKI KX125
CYCLE WORLD TEST
Less Weight and More Power Make This One the Favorite in Class
Hard on the heels of Kawasaki's excellent KX250 comes another motocrosser in the same vein, the KX125. Like big brother, the 125 is light, and powerful, and you may need influence to get one.
At first glance the KX125 iS just like the 250, only scaled down a bit. It's flashy green with gold-colored alloy wheel rims, swing arm and front engine mounting plates. The whole package radiates an air of quality. The welds on the swing arm, for instance, are beautifully executed, showing care and pride by the welder.
The front forks have tins on their lead ing edge below the axle. Above the axle. thefr slider castings are thoughtfully pro~ tected by a rubber cover. These effectively protec*the.castings from damage by flying stones The fork seah and s~mnchion tubes are also protected from tiud axid missile damage by good accord ian type~ boo1s'~'
The triple clamps are naturaUvaluniinum but don t have rear-set handlel,th moutHs"
The main frame~ utilizes .~Qhrqme-fl1oJy steel tubing and its sh tp~ i~ slnl!11r to the 250 The teerii~ig head has tape*'e4 roUer bearings and is he~wily gusseted Tri~ angulation betv~een singk downtube~ and backbone tube is~ccomplisbed b~ connecting th~ two with asm1the..~
Tv~o small tubesc~aTdle the eng~.e~and run from the bàj~om of the f~ont.dov~nttt~ rearward under the engiI~e the~ c~irve up~ wardand forward to meet the niair~. backhone tube A large gusset plate i~ to the inside radius of th!~ tubes and thc s~ ing arm is attached to tlt~~ vi a ho1lo~ bolt Just bchind this bo~an~ther equal sized tube is connected an~g~e~ up and back to th~seat ratis
This nicely .~riängulate~ the area below tht se?t 1tnd IcaV~ rooiflt to~ a j~L~stiç~ airbox Tf?e bc~ç cmt tii~ a foa~1t~r that i~, easily r~mOved through the side TIit.. pL~stic sit~plat~ .overs (hii~ pe~in~ md a big lipped i~mt rke at ifietop lets pIer~h or air in anti keeps itiosi w iter out The Irarne i~ tet up~to t11o~v a m~JdIy anhJever~d ho~k poSIt~iQfl
ng remote re~e~oir KYB h~ocs~ie~ andard. Ours worked weIJ.ind~ spri.n~ rates are right on. mpLng i~nt' radjtistabk but is rnblem occurs (i se~i1 leik or F~en h etc.r rep1ac~jn~nt,~.. wiD~ he eces~ar~. ause the shbc.ks aren't rebuI1dabk.~
The litth~sere~ner employs i 1o~ratio 6 speed tran~missi~n with ratios p~i tecth matched tothe~engine's o~er ovtput: The center ases ar~ small and jhe drive sprocket is located fai~iy close to the s~'ing arm pivot. This means chain tension will stay more nearly constanP~ whe't~ the rear suspension operat~es~'
Some of the engine's components have been around for several years, in fact the factory racing guys say this engine began life as a rotary valve unit, then was con verted to piston port and now has a reed valve. Be that as it may, the engine is modern and powerful enough to be con sidered new.
Again like the KX250. the 125's features begin with the bore. The cylinder is alum i num. There is no liner in the usual sense. Instead, Kawasaki has a patented process, called Electrofusion.
Thin wires, some of high-carbon steel and some of molybdenum. are electrically heated to the point of explosion inside the cylinder. The exploding particles imbed themselves in the cylinder wall. This is repeated several times, with alternating types of wire. The result is a steel bore, lighter and with better heat transfer than the usual steel liner. The moly wires give some lubrication and Kawasaki engineers say their process also has the benefits of a chrome surface and won't peel, although the owner's manual warns that the Elec trofused cylinder can't be re-bored and that port matching and smoothing better be done with maximum care.
A 32mm Mikuni feeds premix through a reed cage big enough to handle a 250. The cage holds Boyesen fiber reeds, which are more responsive to engine demands and also are digestible, so to speak. if a reed breaks off and disappears into the engine.
The 125 engine gets increased induction time by feeding mix through the reed cage and then into the crankcase via a square port in the piston's skirt. There are also has at least 22 bhp. No fear. The same men say the other current massscavenge ports to pull in mixture from the tract when pressure closes the reeds. Trans fer and exhaust ports are equally huge and the exhaust pipe matches port timing in that the emphasis is on power. The KX 125 has that. The factory claim is 26.9 bhp. Professional tuners who'll talk say the production 125 produced 125 motocross engines have less. The KX has finning in keeping with the power output and we noted no appreciable loss in performance after many hard laps. The powerband is narrow, as it must be on any competitive 125. This is a machine for experts and experts shouldn't have any trouble making the engine work for them.
The 125's clutch is large and strong. The lever pull is soft and the unit completely disengages without drag or chatter. Unfor tunately engagement is sudden. Forget about trying to slip or gradually engage it.
It is either in or out, like a toggle switch. On a 125 motocrosser this type of action isn't too objectionable. though. When fan ning the clutch or rebounding from a berm, this form of instant engagement is actually beneficial.
The little Kawasaki has beautiful coni cal hubs front and rear. The rear one is magnesium and has a full-floating brake backing plate. The torque arm pivots on roller bearings. The brake pedal is a lovely aluminum forging that tucks into a recess in the clutch cover and has a good height> adjuster. Too bad that with all of these nice things going for it, the rear brake, like the clutch, is an all-or-nothing proposition. One of the touchiest units we have tested lately. It will stop the engine instantly if used in a normal manner. With practice the rider can adjust but a more progressive action would be better.
KAWASAKI KX125
Forks on the KX1 25 are the same units found on the 250. Travel is ample and spring and damping rates are excellent. By changing oil viscosity and weight and air pressure, the front end can be tuned for a wide range of rider and track variations.
These DeCarbon-type remote-reservoir shocks are similar to the units found on the KX250. They're an inch shorter, at 16.5, and have slightly less travel. Damping rates are greater than the 250's, and spring rates are comparable. The result is a rear suspension set-up that works extremely well.
Tests performed at Number 1 Products
The front brake is almost the opposite. It is strong. progressive and works admirably.
Lever pressure required to apply the brake is just right and the heavy-duty control cable is firmly held to the fork leg by two cable clamps. An excellent touch.
The little screamer's spokes and chain (428H?) look small but we didn't have any problems with them. Their sizes are con sidered adequate by Kawasaki's engineers.
By keeping them just large enough to do their job, weight is kept to a minimum.
The effort directed toward weight reduc tion is incredible. Every bolt that is large enough to be hollow, is. Axle bolts, swing arm pivot bolt, even the brake camshafts are hollow. All cap screws arc of the dished-head design.
The KX has a plastic (green. naturally) gas tank and fenders. The tank is slim and has a nice, shape. It is mounted to the frame by beautiful aluminum brackets. These look much stronger than the stamped steel ones some manufacturers use.
Like the tank, the seat is narrow to allow movement on the machine. Although nar row, it is very comfortable. -
The KX drew much attention at all our test sites. Its color combination and atten tion to detail are instantly noticed by other riders. "Sure is pretty," "How much does it cost?,"" What does it weigh?." "Is it fast?," "Wow, everything is drilled br lightness!." "Sure has a nice welds on the swing arm"all were common questions and com ments.
The peg-seat-bar relationship is good except for bars that are too wide. By cut ting an inch off of each end, their size will match the bike better. While you are cut ting. cut off the fat grips and deposit them in the trash. They are so big they pump up the rider's forearms almost immediately.
The 125 starts easily and like all 125 MXers, works best if the throttle is kept wide open most of the time. The engine puts out more than enough beans to be competitive; a narrow powerband is the price you pay.
Trying to square corners on the 125 is usually a mistake. Corners are best as saulted by going into them hard and riding through with the throttle wide open. Natu rally the shift lever gets almost constant use to keep the power at its peak. The slick shifting 6-speed works smoothly and no one missed a shift with it.
The KX's light weight and excellent suspension are readily noticed. All sizes and shapes of holes and bumps are smoothed out without excessive pitching or bucking.
The forks' 9 in. of travel is enough for almost all situations and modifications won't be necessary. Although the shocks look the same as those used on the 250, the 125's worked better. They offer 8.5 in. of rear wheel travel without getting hot and fading. Damping and spring rates are matched well to the weight and usage of the machine.
Steve Bauerjumped the KX off of some banks that were 6 ft. high. Although the landing spot was flat and hard, the little bike took the repeated flogging without complaint. The suspension absorbed the landings well and rider control was easily maintained.
With a 55-in. wheelbase. 30-deg. rake and 5.1 in. of trail, handling is a bit slowjust the opposite of its shadow, the KX250. This makes it feel heavier than the sub200-lb. the scale shows. These measurements also add stability at higher speeds. As you might suspect, it is a dynamite machine on high-speed, bumpy courses. On tight twisty tracks, a little more quickness might be better.
It looks as if Kawasaki can add another winner to its list. The KX125-A4 doesn’t have a normal list price. It will be marketed like the 250. Dealers can sell them for whatever they can get or perhaps sponsor a local racer. Production is limited, quality is high. Interested buyers best start bugging their dealers now. |§
