reepicheep
Member
- Apr 3, 2009
- 670
- 2
I recently went from a KLR-250 to a KDX-200 (well, 225 now) and am sold on two strokes for trail bikes. The KLR was fun as a light little street bike, but moving to the KDX meant I lost 60 pounds and gained 20 HP. I also had to do a top end rebuild on the KLR... which I thought was a lot of work but straightforward until I rebuilt the KDX top end. I laughed out loud it was so easy.
Anyway, so my 9 year outgrew the neighbors XR50 he was riding, and it was time for a new bike. Found a 2000 KX-60 (which turned out to be a 1990 KX-60, gotta love Craigs List) that wasn't running but looked more or less intact.
The stated reason the bike wasn't running was because the stator was shot, and sure enough it was. Don't buy the Kawasaki part, Ricky Stator doesn't list the KX-60 part on their site, but they do carry and sell it, and know exactly what you need. Great folks to deal with, and fantastic prices relative to stock. And really cool stickers for the kids bike as well.
The bike "with a brand new piston" of course needed a new piston as well. I mentioned this was one of those craigslist deals, right? The piston in there was clean, and in backwards, and missing a chunk of the crown, and it has pressed some tiny bit of steal wire looking bit into the head and piston. Like 1mm of circlip or something. I went with the Namura which sells cheap on ebay. It obviously isn't as good as a Weisco, but it looked a lot better then the stock Kawasaki that it replaced. Not a brand to impress your buddies with, but people that use them in both bike shops and snowmobiles seem happy with them, and I am in that camp. I tore it back down after maybe 10 hours of use, and it looks to be wearing just fine, and compression is great.
The bike came with a "PSI" aftermarket header, with what looks like an FMF silencer. Never heard of PSI before now, but apparently they are big in the snowmobile world. Whatever, somebody put a heck of a lot of welding work into that silencer, it is built up from a bunch of individual 2" wide rings of metal of varying diameters, all welded together. Lots of welds on stainless, and it looks like TIG. Really nice work. No idea if it is a woods/torque or desert/rev header, but knowing the KX-60, everything seems to be geared for rev/desert/mx/race.
Which (finally) brings me to my topic... the bike was a lot of fun for my kid around the street. Took him no time at all to find the power band...
http://www.youtube.com/watch?v=wl9Y1tU-dkA
But the tradeoffs of an MX bike became apparent on our first "40 degree muddy greasy sticky woods riding" day. That poor thing was clogged to every gill with ohio mud everywhere, to the point where it simply wasn't possible to go anywhere in 2nd gear. I suppose if you pinned the throttle, kept it in that razor thin power band, and slipped the clutch constantly you could in theory move, but that's not second gear, that's just first gear but with a burnt clutch.
Jack isn't going to race MX, we are woods riders, and we are both really excited about doing some father son Enduros this summer.
So the transformation began... how to turn a KX-60 into a mythical KDX-60. :)
It turned out pretty simple. The front sprocket went down to a 13 tooth, which is about as small as I have ever been comfortable going without undue wear and tear on the sprocket and chain. Though now that I think about it as I type this, a KX-60 is a 420 instead of a 520 chain, and only 20 or so HP, so a 12 front would probably be fine. I'm not sure what stock was, but the previous owner had a 14 tooth sprocket on there. I'll have to put a 12 tooth front on the "next order list".
I switched the rear sprocket to a 48 tooth (I think stock is 44). A little pricey at $38 or something, but it did the job.
I put in Boyesen two stage reeds in place of stock (610's), and picked up a Moose "torque spacer". Just a machined aluminum spacer that sits between the reed block and the motor to move the powerband lower in the RPM range.
Jetting on the bike is a 210 main, not sure what the slow jet is, but whatever it is it is still too rich... it'll flood when you try and start it, even cold, with any throttle or any choke.
I also repacked the exhaust... less is more for these little bikes. With insulation packed in there tight, it ran really bad (on throttle stumble). With loose insulation, it ran great. I just used fiberglass wall insulation as I had it around.
I also got a cheap Dennis Kirk IRC "kids motocross" tire, which was absolute and total junk. I ended up ruining it mounting it, which was probably for the better anyway, as the knobs on the thing were pathetic anyway, and judging by how easily the steel bead wire ripped right out of the rubber bead, I don't want it any bike my kid is on anyway. I replaced it with a Pirelli scorpion, which was a much nicer tire, and had maybe 14mm high knobs, instead of that IRC mess (maybe 7mm?).
The results were great! It pulls a lot harder, it'll wheelie in 2nd gear on pavement now, which bodes well for working through mud and woods. And I now don't have a 9 year old on a bike that will approach 60 mph wound out in 6th. Nor do I have a kid frustrated because he has a bike with a peaky little narrow powerband.
The gearing is a slam dunk, do it. I am not as sure about the torque spacer. It seems to do a pretty good job, but now the carb is back further, and the "air tube" between it and the carb is pretty tight, and slightly kinked. Also, the choke lever on the carb now interferes with the airbox, so I am going to have to do some melting / cutting to get clearance to be able to use the choke. It's the "outside the filter" part of the airbox, so not a huge deal, but it's going to take a little fabricating. A hot screwdriver to the airbox was enough to get clearance to get things to mount up if you don't use the choke (which I don't at the moment, because the bike is way too rich). I'll probably pull it apart tonight and figure out if I can just melt and bend to get enough room for the choke, or if I have to carve a hole and reseal it somehow. I could carve a hole and leave it open easily, but that would give him maybe 1-2" less "water crossing" depth before the motor has a drinking problem... on a bike as low to the ground as a KX-60 is already, I hate to give up that much.
The alternative of course would be to get him an XR 80 or something... but that is a pretty heavy bike. I think this KX-60 is lighter then the XR-50 he used to ride. And the suspension on the KX-60 is fantastic... maybe even better then my KDX. The two things that keep it from being a good enduro / woods bike is (1) narrow power band and (2) short fuel range. And two strokes are just SOOOO easy and cheap to maintain, and make such good power.
It's a shame they don't make a modern KDX-80. A KX-60 but with 80cc's, a power valve, a bigger tank with reserve, aluminum rims, and geared way low, but still about the same size as the KX-60. Not likely though, as they don't even make a modern KDX-200 now :(. I guess I'll have to wait for the direct injection two stroke servo controlled power valve barely street legal KDX-350. That'd be my dream bike.
So the KX-60 is now close, and didn't cost much to get there. $450 to buy (probably over paid, but it was before Christmas and there weren't many options). $150 or so to get running again and refresh the stickers and new rear fender, maybe another $150 to get "enduro ready" with the sprockets, reeds, and torque spacer... but the sprockets had to be replaced anyway.
It still has a small tank with shorter range, but Dad is riding right beside him with a KDX-200... I'll have to stash a siphon somewhere on my bike. I'm his reserve :). And where we ride in Ohio, running back to the truck a few times during the day is no big deal. And its still a little motor, so it does OK on fuel, just not as good as the XR-50 (which runs about a year and a half between fuel ups ;) ).
I'll post another update after our first serious woods ride.
Anyway, so my 9 year outgrew the neighbors XR50 he was riding, and it was time for a new bike. Found a 2000 KX-60 (which turned out to be a 1990 KX-60, gotta love Craigs List) that wasn't running but looked more or less intact.
The stated reason the bike wasn't running was because the stator was shot, and sure enough it was. Don't buy the Kawasaki part, Ricky Stator doesn't list the KX-60 part on their site, but they do carry and sell it, and know exactly what you need. Great folks to deal with, and fantastic prices relative to stock. And really cool stickers for the kids bike as well.
The bike "with a brand new piston" of course needed a new piston as well. I mentioned this was one of those craigslist deals, right? The piston in there was clean, and in backwards, and missing a chunk of the crown, and it has pressed some tiny bit of steal wire looking bit into the head and piston. Like 1mm of circlip or something. I went with the Namura which sells cheap on ebay. It obviously isn't as good as a Weisco, but it looked a lot better then the stock Kawasaki that it replaced. Not a brand to impress your buddies with, but people that use them in both bike shops and snowmobiles seem happy with them, and I am in that camp. I tore it back down after maybe 10 hours of use, and it looks to be wearing just fine, and compression is great.
The bike came with a "PSI" aftermarket header, with what looks like an FMF silencer. Never heard of PSI before now, but apparently they are big in the snowmobile world. Whatever, somebody put a heck of a lot of welding work into that silencer, it is built up from a bunch of individual 2" wide rings of metal of varying diameters, all welded together. Lots of welds on stainless, and it looks like TIG. Really nice work. No idea if it is a woods/torque or desert/rev header, but knowing the KX-60, everything seems to be geared for rev/desert/mx/race.
Which (finally) brings me to my topic... the bike was a lot of fun for my kid around the street. Took him no time at all to find the power band...
http://www.youtube.com/watch?v=wl9Y1tU-dkA
But the tradeoffs of an MX bike became apparent on our first "40 degree muddy greasy sticky woods riding" day. That poor thing was clogged to every gill with ohio mud everywhere, to the point where it simply wasn't possible to go anywhere in 2nd gear. I suppose if you pinned the throttle, kept it in that razor thin power band, and slipped the clutch constantly you could in theory move, but that's not second gear, that's just first gear but with a burnt clutch.
Jack isn't going to race MX, we are woods riders, and we are both really excited about doing some father son Enduros this summer.
So the transformation began... how to turn a KX-60 into a mythical KDX-60. :)
It turned out pretty simple. The front sprocket went down to a 13 tooth, which is about as small as I have ever been comfortable going without undue wear and tear on the sprocket and chain. Though now that I think about it as I type this, a KX-60 is a 420 instead of a 520 chain, and only 20 or so HP, so a 12 front would probably be fine. I'm not sure what stock was, but the previous owner had a 14 tooth sprocket on there. I'll have to put a 12 tooth front on the "next order list".
I switched the rear sprocket to a 48 tooth (I think stock is 44). A little pricey at $38 or something, but it did the job.
I put in Boyesen two stage reeds in place of stock (610's), and picked up a Moose "torque spacer". Just a machined aluminum spacer that sits between the reed block and the motor to move the powerband lower in the RPM range.
Jetting on the bike is a 210 main, not sure what the slow jet is, but whatever it is it is still too rich... it'll flood when you try and start it, even cold, with any throttle or any choke.
I also repacked the exhaust... less is more for these little bikes. With insulation packed in there tight, it ran really bad (on throttle stumble). With loose insulation, it ran great. I just used fiberglass wall insulation as I had it around.
I also got a cheap Dennis Kirk IRC "kids motocross" tire, which was absolute and total junk. I ended up ruining it mounting it, which was probably for the better anyway, as the knobs on the thing were pathetic anyway, and judging by how easily the steel bead wire ripped right out of the rubber bead, I don't want it any bike my kid is on anyway. I replaced it with a Pirelli scorpion, which was a much nicer tire, and had maybe 14mm high knobs, instead of that IRC mess (maybe 7mm?).
The results were great! It pulls a lot harder, it'll wheelie in 2nd gear on pavement now, which bodes well for working through mud and woods. And I now don't have a 9 year old on a bike that will approach 60 mph wound out in 6th. Nor do I have a kid frustrated because he has a bike with a peaky little narrow powerband.
The gearing is a slam dunk, do it. I am not as sure about the torque spacer. It seems to do a pretty good job, but now the carb is back further, and the "air tube" between it and the carb is pretty tight, and slightly kinked. Also, the choke lever on the carb now interferes with the airbox, so I am going to have to do some melting / cutting to get clearance to be able to use the choke. It's the "outside the filter" part of the airbox, so not a huge deal, but it's going to take a little fabricating. A hot screwdriver to the airbox was enough to get clearance to get things to mount up if you don't use the choke (which I don't at the moment, because the bike is way too rich). I'll probably pull it apart tonight and figure out if I can just melt and bend to get enough room for the choke, or if I have to carve a hole and reseal it somehow. I could carve a hole and leave it open easily, but that would give him maybe 1-2" less "water crossing" depth before the motor has a drinking problem... on a bike as low to the ground as a KX-60 is already, I hate to give up that much.
The alternative of course would be to get him an XR 80 or something... but that is a pretty heavy bike. I think this KX-60 is lighter then the XR-50 he used to ride. And the suspension on the KX-60 is fantastic... maybe even better then my KDX. The two things that keep it from being a good enduro / woods bike is (1) narrow power band and (2) short fuel range. And two strokes are just SOOOO easy and cheap to maintain, and make such good power.
It's a shame they don't make a modern KDX-80. A KX-60 but with 80cc's, a power valve, a bigger tank with reserve, aluminum rims, and geared way low, but still about the same size as the KX-60. Not likely though, as they don't even make a modern KDX-200 now :(. I guess I'll have to wait for the direct injection two stroke servo controlled power valve barely street legal KDX-350. That'd be my dream bike.
So the KX-60 is now close, and didn't cost much to get there. $450 to buy (probably over paid, but it was before Christmas and there weren't many options). $150 or so to get running again and refresh the stickers and new rear fender, maybe another $150 to get "enduro ready" with the sprockets, reeds, and torque spacer... but the sprockets had to be replaced anyway.
It still has a small tank with shorter range, but Dad is riding right beside him with a KDX-200... I'll have to stash a siphon somewhere on my bike. I'm his reserve :). And where we ride in Ohio, running back to the truck a few times during the day is no big deal. And its still a little motor, so it does OK on fuel, just not as good as the XR-50 (which runs about a year and a half between fuel ups ;) ).
I'll post another update after our first serious woods ride.