It was never my intent to do this trail test, but with the hours I spent adjusting this, replacing that, I felt it was well deserved.
A friend had been complaining about how poorly his custom-made trail bike was running, a KDX-powered KX125. Whenever he’d have it out, it would run shoddy. And I was partly to blame, persuading him to buy it from the fabricator. Therefore I suggested whilst I had all this time off, that I’d determine the source of his woes. My only payback was to let my middle son, Shorty, take it out one day to see if he could be persuaded onto something other than an XR200/250 which he admires deeply; so deeply there was no sense in arguing with him on what would be his next bike in the event I was able to secure one just for him. He was saddened as he saw the $ for a ’99 Husky WR125 go to my wife’s new (to her) four door of late - I thought him riding this would only cheer him up.
The symptoms of the sad state of affairs with this little mean-green machine showed itself as fuel starvation. The float bowl was set way too low, thanks to the help/directions posted on our own Canadian Dave’s JustKDX website. But being the perfectionist I am, that was the last thing I corrected as the levers were set too high (good for sit-down riding only); the shifter and brake pedal too low - can’t have those rocks contact boots, now; a missing bolt here and there; spooge coming from a gap in the stinger/muffler union needing RTV; and on and on it went - I didn’t get to the fix until well after dark; but that’s the way I am - picky about bike setup/prep.
So as I awoke the morning of the ride, thinking: why not enjoy the fruit of my labor? On the one hand, all I needed to do was to swipe a main jet out of my RMX, and take a risk at meeting a ranger - you see, my friend never affixed a green sticker. But on the other, how often does one get to spend time on a custom, one-off machine like this?
Therefore I had Jr. load the greenie. And I was glad I did. Read on:
The previous owner happened upon a ’98 KX chassis, sans forks. Into it he wedged a ’90 KDX engine, and graced the front with RMX conventional forks. This thing has “trail ride me” all over it; all the more tempting to take it for a spin.
Now mind you, I have never ridden a KDX off road, only up and down the street - four of which I was considering buying, and one had fins - not the aquatic type either. Therefore I did not know what to expect, but only what I read here and to a lesser degree elsewhere. I figured it would certainly outpace an XR250 (one of which I briefly owned), but expected something along the lines of my old IT175; perhaps like my RMX but with a little less boost. Don’t get offended by what I am about to say, though I did have high expectations.
The Engine. A KDX mill is certainly one of the most electric-like in delivery of any two stroke I’ve been on. It’s like “where’s the hit?” that could be good or bad. But perhaps it’s best it does not have one (a hit); that is why it makes such a fine, sedate trail engine. It would happily pull skinny-old-me along without a hitch all day if need be, and not go much faster at middle RPMs than the uppers. It wasn’t ‘til I revved it like a 125 - and kept it there - when it got to serious moving; if the RPMs would drop there was a slight delay in getting it back up, even with clutching. This motor could simply use more beans, being stock except custom-singered FMF Fatty. It could certainly be better with Eric Gorr or Jeff Fredette’s massaging in the porting arena. What I wouldn’t want to change about it is the willingness to go and not kill you at any RPM - a good characteristic for survival riding situations.
Transmission. Gear selection was paramount, perhaps not as much as on a 125 (I don’t do MXers); nonetheless one needs to pay more attention than when on a 250. No surprises here - I’ve gotten lazy in my aging. The six-speed pretty much covers any situation.
Chassis. Now here is a winner. What more can I say than what can be inferred? The KX shock is excellent; the RMX fork - very good, but sprung for a 10-lb heavier machine, so this one needs lighter springs, although the action was good, it reamins on the stiff side.
Handling. Being lighter is welcome. The thing turned quite well, and did good in the whoops; if it had more power, it may even master the latter.
In summary, this is one fine trail bike; maybe even a superb tight/tough enduro mount; although having small lungs limits it’s desert prowess. But for my son (and perhaps even for some tought/tight enduros for me) it would make an excellent mount and reason to forgo valves and cams.
A friend had been complaining about how poorly his custom-made trail bike was running, a KDX-powered KX125. Whenever he’d have it out, it would run shoddy. And I was partly to blame, persuading him to buy it from the fabricator. Therefore I suggested whilst I had all this time off, that I’d determine the source of his woes. My only payback was to let my middle son, Shorty, take it out one day to see if he could be persuaded onto something other than an XR200/250 which he admires deeply; so deeply there was no sense in arguing with him on what would be his next bike in the event I was able to secure one just for him. He was saddened as he saw the $ for a ’99 Husky WR125 go to my wife’s new (to her) four door of late - I thought him riding this would only cheer him up.
The symptoms of the sad state of affairs with this little mean-green machine showed itself as fuel starvation. The float bowl was set way too low, thanks to the help/directions posted on our own Canadian Dave’s JustKDX website. But being the perfectionist I am, that was the last thing I corrected as the levers were set too high (good for sit-down riding only); the shifter and brake pedal too low - can’t have those rocks contact boots, now; a missing bolt here and there; spooge coming from a gap in the stinger/muffler union needing RTV; and on and on it went - I didn’t get to the fix until well after dark; but that’s the way I am - picky about bike setup/prep.
So as I awoke the morning of the ride, thinking: why not enjoy the fruit of my labor? On the one hand, all I needed to do was to swipe a main jet out of my RMX, and take a risk at meeting a ranger - you see, my friend never affixed a green sticker. But on the other, how often does one get to spend time on a custom, one-off machine like this?
Therefore I had Jr. load the greenie. And I was glad I did. Read on:
The previous owner happened upon a ’98 KX chassis, sans forks. Into it he wedged a ’90 KDX engine, and graced the front with RMX conventional forks. This thing has “trail ride me” all over it; all the more tempting to take it for a spin.
Now mind you, I have never ridden a KDX off road, only up and down the street - four of which I was considering buying, and one had fins - not the aquatic type either. Therefore I did not know what to expect, but only what I read here and to a lesser degree elsewhere. I figured it would certainly outpace an XR250 (one of which I briefly owned), but expected something along the lines of my old IT175; perhaps like my RMX but with a little less boost. Don’t get offended by what I am about to say, though I did have high expectations.
The Engine. A KDX mill is certainly one of the most electric-like in delivery of any two stroke I’ve been on. It’s like “where’s the hit?” that could be good or bad. But perhaps it’s best it does not have one (a hit); that is why it makes such a fine, sedate trail engine. It would happily pull skinny-old-me along without a hitch all day if need be, and not go much faster at middle RPMs than the uppers. It wasn’t ‘til I revved it like a 125 - and kept it there - when it got to serious moving; if the RPMs would drop there was a slight delay in getting it back up, even with clutching. This motor could simply use more beans, being stock except custom-singered FMF Fatty. It could certainly be better with Eric Gorr or Jeff Fredette’s massaging in the porting arena. What I wouldn’t want to change about it is the willingness to go and not kill you at any RPM - a good characteristic for survival riding situations.
Transmission. Gear selection was paramount, perhaps not as much as on a 125 (I don’t do MXers); nonetheless one needs to pay more attention than when on a 250. No surprises here - I’ve gotten lazy in my aging. The six-speed pretty much covers any situation.
Chassis. Now here is a winner. What more can I say than what can be inferred? The KX shock is excellent; the RMX fork - very good, but sprung for a 10-lb heavier machine, so this one needs lighter springs, although the action was good, it reamins on the stiff side.
Handling. Being lighter is welcome. The thing turned quite well, and did good in the whoops; if it had more power, it may even master the latter.
In summary, this is one fine trail bike; maybe even a superb tight/tough enduro mount; although having small lungs limits it’s desert prowess. But for my son (and perhaps even for some tought/tight enduros for me) it would make an excellent mount and reason to forgo valves and cams.
