2000 KDX200 almost complete rebuild review
Posted: 02:36 pm Oct 11 2019
I decided a review might be the best place to describe the work I have done and the results of that work. During the course of the rebuild I replaced/upgraded/changed many things and I’ll try to comment on them as objectively as possible. This is long and my grammar is terrible so look away now if you are bothered by that. I will include a ride report and non-objective impressions at the end.
Backstory: I purchased this bike in late 2018 as a mostly basket case project that had been neglected by the previous owner. The lower end rod bearing rollers had liberated themselves from the cage and done a lot of damage to the piston, cylinder, and head. The cylinder and other pieces were already removed when I purchased it. I needed a winter project and after 16yrs away from riding nostalgia got the best of me.
Bottom end: the transmission gears showed no major signs of wear. Out of an abundance of caution I replaced all the bearings in the case halves and covers. The clutch plates and springs measured in spec and I have been using them as the bike was purchased. Likely the clutch will be replaced this winter but has been serviceable for my use.
Crankshaft: I made the choice to learn how to replace a crank pin and true the crank. I purchased a Pro-X rod and bearing kit and got to work. This job is not for beginners and I honestly questioned my choice in doing it. Someone could easily get in over their head attempting this and really damage a crank. Once I was done the crank was measuring total runout at or under .0003 but that took a lot of work. In hindsight I WOULD pay a reputable shop to do this portion of the job on a jig.
Water pump: The mechanical seal gave me issues. Driving this in it seems easy to over stress the plastic portion ruining the seal. I did this and the bike promptly puked all its coolant the first time I filled it. I replaced the seal and was much more delicate with a better result.
Kips governor: No issues here, it seems like a decent design on the bottom end side.
Kicker: didn’t wind it up far enough leading to a lack of return. I fixed this when replacing the mechanical seal on the water pump.
Top End: I sent the cylinder and a new-used head to Eric Gorr for a 225 oversize and mo-better porting with an emphasis on low end. I also requested it be setup for 91-Octane pump gas as that is what is available around my area as Ethanol free. I was happy with the work that he did on the plating and porting. There were no signs of porosity in the plating and I scrutinized it thoroughly. The port work was executed very cleanly with nice smooth transitions and little to no “chatter” marks from amateur type work. The one let down with this is minor but worth reporting. > You send Eric the whole cylinder, studs, power valves, and all. I like this feature because a lot of other shops want everything removed before you send it and porting without a power valve to match up to the port seems sketchy. Also, when it’s returned it is reassembled. I got it back and during my inspection noticed one of the rotating kips valves (in side ports) seemed to be moving (axially) more than the other. I disassembled the KIPS and found that one of these valves had the stabilizing post broken off. I’m sure it was broken before Eric and his guys started work and I don’t fault him for that in anyway. I just would have liked a note stating it was broken with the completed cylinder. I could have very easily put it back together as it arrived and never known then chased the issue assuming those parts were good. I used the Wiseco Piston pin and bearing that Eric supplied and reassembled the cylinder to the bottom end with the top end (Cometic) gasket set Eric provided.
Reeds: Reeds and reed cage are stock
Carburetor: Other than disassembly and cleaning the carb is the same as when I purchased the bike. The jetting is probably a little rich on the pilot, but it didn’t like one size smaller very much. With the temps and humidity dropping it is enjoying the benefits of greater air density. There is some black spooge that doesn’t want to tune out. I tried to use Tusk idle and air screws, but they don’t fit the bike well and the threads weren’t going easily so I abandoned that pursuit. I have been considering a Lectron for no other reason than my own laziness. I’m sure this stock carb or an RB unit can be tuned up to run great with the right needle and jet changes, but my riding/wrenching time is so limited I would rather forego that moving target game.
Exhaust: The bike had an FMF gnarly pipe and powercore II silencer. I repacked the silencer and did what I could to remove carbon from the pipe. This setup seems to be favored for these bikes, so I saw no need to change out any of the components.
Final drive: Sprockets I went with Primary drive steel front and rear. On size I used 13T front and 51T rear. I had concerns with the bike having enough torque to get my 215lb heft moving. This combined with planning on riding mostly tighter trail led to my size choices. I chose steel because I was hoping they would last a bit longer than aluminum and I didn’t have plans of racing so shaving the weight didn’t seem to be a priority. For a chain I started with a primary drive O-ring but was unhappy with the clearance to the engine case at the front sprocket. I wound up getting a standard chain and was much more comfortable with the fit. The standard chain hasn’t stretched much, I adjusted the axle one notch further back at 3hrs
Suspension: After a few rides I decided the front was far too soft and wanted to dive hard any-time the front brakes were touched. I’m not a suspension guru so I used the calculator on race techs site and bought some new springs. Along with new oil, bushings, and seals this got the forks feeling much better. The bike holds a nice line in the turns and no longer dives under breaking. The rear is sufficient after I adjusted the ride height, but it could probably benefit from an oil change and rebuild. I plan on doing this once the ground is white. It was clear that part of this bikes neglect was the linkage bearings. One of the dog bone bolts was held in with zip ties when I got the bike home. I replaced every bearing in the linkage and pivot.
Controls: The bike had some pro taper bars on it they seem to be a decent fit, I might consider a slightly higher bend if I ever replace them. I kept the levers stock just replacing the broken pieces with parts from Rocky Mountain. The fit and function on the rocky mountain parts was quite good for the price. Pro taper pillow grips got put on and they feel just right to me with some cushion without being “squishy” I fitted a set of d-flex hand guards and they have already saved my fingers a few times. I’m happy I chose to put these on, they aren’t super easy to install and required some bending. That should probably be expected of a universal type part.
Tires/wheels: I went with Kenda K760 Trakmasters front and rear. These have an aggressive pattern for a DOT stamp tire. They seem to grip well on the mostly soft but not loose surfaces I have ridden. They can put down power efficiently if you want but also will spin/slip if the situation calls for it. I like them and at the modest price point there isn’t much risk in giving them a try. The rims are stock units that have seen better days.
Seat: I recovered the original seat with a cover from e-bay. Enjoy is the brand and it seems to be of decent quality so far, no issues. I will say that with the aggressive “rider pocket” on this seat and a gripper seat cover you have to work a little to shift your riding position.
Cosmetics: I did what I could to clean up the plastics and it seems passable to me but probably not drawing envy from anyone. I like the fender bag as it allows me to keep a plug and plug wrench with the bike at all times even though I haven’t needed it. Stickers aren’t really my thing so there aren’t any graphics on the bike. I polished most every aluminum piece that I removed, it was motivated mostly as a way to keep dirt from sticking to those surfaces but changed the look of many parts of the bike. I spent the time and nickel plated and polished all the bolts, nuts, washers, and steel parts that were removed at some point. This was a major time investment but getting done with a project and seeing the same old rusty bolts probably irritates more people than just me.
Ride Review: What can I say, this thing has blown me away with the level of performance it gets from a smallish engine. I struggle too see why people need 300cc bikes. The Eric Gorr kit with the FMF pipe seems to just work. The bike makes loads of torque to the point where I’m considering resizing the sprockets to make it more manageable. The gears are short from the sprocket sizing but the thing rips and has floated (unexpectedly) the front wheel in 4th. I’m not sure if its power valves or they were just clapped out junk, but this is nothing like the 2 stroke bikes of my youth. I am getting more used to riding it, yet I can’t help but feel like it is trying to kill me anytime I go past half throttle. Since finishing this I’ve only been able to put together about 5hrs of seat time with all my other obligations. I would say that this project was worth it for me because I enjoyed the process almost as much as the payoff. If that isn’t how you view these things rebuilding a bike probably isn’t for you. I learned a ton about 2 strokes that I had very little firsthand experience with. (I was an automotive mechanic for years) It was a project I’m glad I picked up and hobby I’m happy to have back after a long hiatus.
Backstory: I purchased this bike in late 2018 as a mostly basket case project that had been neglected by the previous owner. The lower end rod bearing rollers had liberated themselves from the cage and done a lot of damage to the piston, cylinder, and head. The cylinder and other pieces were already removed when I purchased it. I needed a winter project and after 16yrs away from riding nostalgia got the best of me.
Bottom end: the transmission gears showed no major signs of wear. Out of an abundance of caution I replaced all the bearings in the case halves and covers. The clutch plates and springs measured in spec and I have been using them as the bike was purchased. Likely the clutch will be replaced this winter but has been serviceable for my use.
Crankshaft: I made the choice to learn how to replace a crank pin and true the crank. I purchased a Pro-X rod and bearing kit and got to work. This job is not for beginners and I honestly questioned my choice in doing it. Someone could easily get in over their head attempting this and really damage a crank. Once I was done the crank was measuring total runout at or under .0003 but that took a lot of work. In hindsight I WOULD pay a reputable shop to do this portion of the job on a jig.
Water pump: The mechanical seal gave me issues. Driving this in it seems easy to over stress the plastic portion ruining the seal. I did this and the bike promptly puked all its coolant the first time I filled it. I replaced the seal and was much more delicate with a better result.
Kips governor: No issues here, it seems like a decent design on the bottom end side.
Kicker: didn’t wind it up far enough leading to a lack of return. I fixed this when replacing the mechanical seal on the water pump.
Top End: I sent the cylinder and a new-used head to Eric Gorr for a 225 oversize and mo-better porting with an emphasis on low end. I also requested it be setup for 91-Octane pump gas as that is what is available around my area as Ethanol free. I was happy with the work that he did on the plating and porting. There were no signs of porosity in the plating and I scrutinized it thoroughly. The port work was executed very cleanly with nice smooth transitions and little to no “chatter” marks from amateur type work. The one let down with this is minor but worth reporting. > You send Eric the whole cylinder, studs, power valves, and all. I like this feature because a lot of other shops want everything removed before you send it and porting without a power valve to match up to the port seems sketchy. Also, when it’s returned it is reassembled. I got it back and during my inspection noticed one of the rotating kips valves (in side ports) seemed to be moving (axially) more than the other. I disassembled the KIPS and found that one of these valves had the stabilizing post broken off. I’m sure it was broken before Eric and his guys started work and I don’t fault him for that in anyway. I just would have liked a note stating it was broken with the completed cylinder. I could have very easily put it back together as it arrived and never known then chased the issue assuming those parts were good. I used the Wiseco Piston pin and bearing that Eric supplied and reassembled the cylinder to the bottom end with the top end (Cometic) gasket set Eric provided.
Reeds: Reeds and reed cage are stock
Carburetor: Other than disassembly and cleaning the carb is the same as when I purchased the bike. The jetting is probably a little rich on the pilot, but it didn’t like one size smaller very much. With the temps and humidity dropping it is enjoying the benefits of greater air density. There is some black spooge that doesn’t want to tune out. I tried to use Tusk idle and air screws, but they don’t fit the bike well and the threads weren’t going easily so I abandoned that pursuit. I have been considering a Lectron for no other reason than my own laziness. I’m sure this stock carb or an RB unit can be tuned up to run great with the right needle and jet changes, but my riding/wrenching time is so limited I would rather forego that moving target game.
Exhaust: The bike had an FMF gnarly pipe and powercore II silencer. I repacked the silencer and did what I could to remove carbon from the pipe. This setup seems to be favored for these bikes, so I saw no need to change out any of the components.
Final drive: Sprockets I went with Primary drive steel front and rear. On size I used 13T front and 51T rear. I had concerns with the bike having enough torque to get my 215lb heft moving. This combined with planning on riding mostly tighter trail led to my size choices. I chose steel because I was hoping they would last a bit longer than aluminum and I didn’t have plans of racing so shaving the weight didn’t seem to be a priority. For a chain I started with a primary drive O-ring but was unhappy with the clearance to the engine case at the front sprocket. I wound up getting a standard chain and was much more comfortable with the fit. The standard chain hasn’t stretched much, I adjusted the axle one notch further back at 3hrs
Suspension: After a few rides I decided the front was far too soft and wanted to dive hard any-time the front brakes were touched. I’m not a suspension guru so I used the calculator on race techs site and bought some new springs. Along with new oil, bushings, and seals this got the forks feeling much better. The bike holds a nice line in the turns and no longer dives under breaking. The rear is sufficient after I adjusted the ride height, but it could probably benefit from an oil change and rebuild. I plan on doing this once the ground is white. It was clear that part of this bikes neglect was the linkage bearings. One of the dog bone bolts was held in with zip ties when I got the bike home. I replaced every bearing in the linkage and pivot.
Controls: The bike had some pro taper bars on it they seem to be a decent fit, I might consider a slightly higher bend if I ever replace them. I kept the levers stock just replacing the broken pieces with parts from Rocky Mountain. The fit and function on the rocky mountain parts was quite good for the price. Pro taper pillow grips got put on and they feel just right to me with some cushion without being “squishy” I fitted a set of d-flex hand guards and they have already saved my fingers a few times. I’m happy I chose to put these on, they aren’t super easy to install and required some bending. That should probably be expected of a universal type part.
Tires/wheels: I went with Kenda K760 Trakmasters front and rear. These have an aggressive pattern for a DOT stamp tire. They seem to grip well on the mostly soft but not loose surfaces I have ridden. They can put down power efficiently if you want but also will spin/slip if the situation calls for it. I like them and at the modest price point there isn’t much risk in giving them a try. The rims are stock units that have seen better days.
Seat: I recovered the original seat with a cover from e-bay. Enjoy is the brand and it seems to be of decent quality so far, no issues. I will say that with the aggressive “rider pocket” on this seat and a gripper seat cover you have to work a little to shift your riding position.
Cosmetics: I did what I could to clean up the plastics and it seems passable to me but probably not drawing envy from anyone. I like the fender bag as it allows me to keep a plug and plug wrench with the bike at all times even though I haven’t needed it. Stickers aren’t really my thing so there aren’t any graphics on the bike. I polished most every aluminum piece that I removed, it was motivated mostly as a way to keep dirt from sticking to those surfaces but changed the look of many parts of the bike. I spent the time and nickel plated and polished all the bolts, nuts, washers, and steel parts that were removed at some point. This was a major time investment but getting done with a project and seeing the same old rusty bolts probably irritates more people than just me.
Ride Review: What can I say, this thing has blown me away with the level of performance it gets from a smallish engine. I struggle too see why people need 300cc bikes. The Eric Gorr kit with the FMF pipe seems to just work. The bike makes loads of torque to the point where I’m considering resizing the sprockets to make it more manageable. The gears are short from the sprocket sizing but the thing rips and has floated (unexpectedly) the front wheel in 4th. I’m not sure if its power valves or they were just clapped out junk, but this is nothing like the 2 stroke bikes of my youth. I am getting more used to riding it, yet I can’t help but feel like it is trying to kill me anytime I go past half throttle. Since finishing this I’ve only been able to put together about 5hrs of seat time with all my other obligations. I would say that this project was worth it for me because I enjoyed the process almost as much as the payoff. If that isn’t how you view these things rebuilding a bike probably isn’t for you. I learned a ton about 2 strokes that I had very little firsthand experience with. (I was an automotive mechanic for years) It was a project I’m glad I picked up and hobby I’m happy to have back after a long hiatus.