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Carburetor de-restricting 2005 KTM SMC 625
Parts needed KTM 57331032000 or modify your restrictor
Tools needed
8mm socket
10mm socket
13mm socket
Common pliers
3mm Allen wrench
4mm Allen wrench
A hacksaw or Dremel with cut off wheel if you do not have 57331032000
Common sense
Super easy job, ½ an hour max you do not need to take off the carb or mess with the cables or throttle linkage.
I did this outside my garage it is just not bright enough for carb work on the bike inside.
All reference to direction is as if you were sitting on the bike
1. Turn your petcock off
2. Pull your vent hose off your gas cap
3. Remove your seat (little lever under the edge of left side panel/seat junction)
4. Remove the eight 8mm bolts that attach the radiator shrouds (be careful, the lower bolt on each side is a different length than the other six. These two lower bolts also have a small aluminum spacer)
5. Remove the 13mm nut at the base (rear of the gas tank) when removing note the order of the rubber and metal washer that accompany this nut
6. Use the pliers to gently squeeze the clamp on the fuel line. While squeezed or expanded slide it up the fuel line about a half inch, past the bulge on the carb fuel line fitting (the fuel line is on the left hand side of the carb. It is a black fabric covered hose
7. Slide the fuel line off the carb fitting, you did turn off the petcock didn’t you? ( a very small amount of fuel will spill)
8. Before you pull you tank find a nice spot to set it
9. Gently pull straight up to remove your tank
10. Hooray! That’s your carb
11. The shiny aluminum casting that has CR molded into it is the top of the carb
12. Carefully remove the two 3mm Allen screws on this cover (one in front, one in rear)
13. It looks like you may have to remove a Phillips cadmium plated screw on the right top of the cover but it is not in the way, leave it alone.
14. Gently pull the top off
15. See that tall bolt looking thing? That is your restrictor
16. You can pull it up to see how the slide works, the slide will not come out
17. See those cool rollers on the slide? In the old days flat slides didn’t have rollers and could get hung up because of the intake suction!
18. Use a 10mm socket and remove the restrictor. That thing is heavy! Now you bike is even a little lighter
19. The restrictor is hollow on the bottom when you pulled it out did you also get a little spring and a cup washer on the spring?
20. If you didn’t it is still in your slide on top of the needle, get it out
21. While the restrictor is out look into the slide, that is your needle
22. If you are modifying your restrictor put it in a vise and cut as much as possible off the top the bolt looking part, not the threads. Remember you still must get a socket on this so don’t cut it too thin. Or cut it off flat and use a hacksaw or Dremel to cut a slot in it to use with a screwdriver If you are not modifying your restrictor you can buy the correct unrestricted replacement “set screw” from KTM 57331032000 (obviously this is a off-road only component) If you want to use a socket cut about 15mm off the restrictor. If you are going to slot it cut all 20mm off.
23. Gently sandwich the spring between the cup washer and the modified restrictor or new set screw whichever you have.
24. The cup washer should be facing up to cradle the spring (cup side up flat side down)
25. Carefully place this assembly back in the slide. Tighten a modified restrictor with a 10mm socket or the new set screw with a 4mm Allen wrench
26. This is a little scary and you do not want to drop anything here, but I have fingers like bratwurst and if I can do it anyone can.
27. Once in place you may pull the slide up with your fingers to help you get started screwing this back in. The angle of the top of the slide and angel the screw goes back in are not 90 degrees, it looks like it could be easy to get cross threaded, take you time here. Tighten
28. Look at the underside of you carb top make sure the rubber gasket is in place. See the shiny spot in the middle? That is where the restrictor kept banging into the carb top when you were kicking your mule to go faster.
29. Put the top back on using the 3mm Allen screws
30. Put the tank back on, reconnect the fuel line, turn the petcock on, check for leaks
31. When replacing the shrouds start the bottom bolts first they are the trickiest. Loosely start all four per side before you tighten them.
32. Put your seat back on.
33. Viola More HP
Scott
Parts needed KTM 57331032000 or modify your restrictor
Tools needed
8mm socket
10mm socket
13mm socket
Common pliers
3mm Allen wrench
4mm Allen wrench
A hacksaw or Dremel with cut off wheel if you do not have 57331032000
Common sense
Super easy job, ½ an hour max you do not need to take off the carb or mess with the cables or throttle linkage.
I did this outside my garage it is just not bright enough for carb work on the bike inside.
All reference to direction is as if you were sitting on the bike
1. Turn your petcock off
2. Pull your vent hose off your gas cap
3. Remove your seat (little lever under the edge of left side panel/seat junction)
4. Remove the eight 8mm bolts that attach the radiator shrouds (be careful, the lower bolt on each side is a different length than the other six. These two lower bolts also have a small aluminum spacer)
5. Remove the 13mm nut at the base (rear of the gas tank) when removing note the order of the rubber and metal washer that accompany this nut
6. Use the pliers to gently squeeze the clamp on the fuel line. While squeezed or expanded slide it up the fuel line about a half inch, past the bulge on the carb fuel line fitting (the fuel line is on the left hand side of the carb. It is a black fabric covered hose
7. Slide the fuel line off the carb fitting, you did turn off the petcock didn’t you? ( a very small amount of fuel will spill)
8. Before you pull you tank find a nice spot to set it
9. Gently pull straight up to remove your tank
10. Hooray! That’s your carb
11. The shiny aluminum casting that has CR molded into it is the top of the carb
12. Carefully remove the two 3mm Allen screws on this cover (one in front, one in rear)
13. It looks like you may have to remove a Phillips cadmium plated screw on the right top of the cover but it is not in the way, leave it alone.
14. Gently pull the top off
15. See that tall bolt looking thing? That is your restrictor
16. You can pull it up to see how the slide works, the slide will not come out
17. See those cool rollers on the slide? In the old days flat slides didn’t have rollers and could get hung up because of the intake suction!
18. Use a 10mm socket and remove the restrictor. That thing is heavy! Now you bike is even a little lighter
19. The restrictor is hollow on the bottom when you pulled it out did you also get a little spring and a cup washer on the spring?
20. If you didn’t it is still in your slide on top of the needle, get it out
21. While the restrictor is out look into the slide, that is your needle
22. If you are modifying your restrictor put it in a vise and cut as much as possible off the top the bolt looking part, not the threads. Remember you still must get a socket on this so don’t cut it too thin. Or cut it off flat and use a hacksaw or Dremel to cut a slot in it to use with a screwdriver If you are not modifying your restrictor you can buy the correct unrestricted replacement “set screw” from KTM 57331032000 (obviously this is a off-road only component) If you want to use a socket cut about 15mm off the restrictor. If you are going to slot it cut all 20mm off.
23. Gently sandwich the spring between the cup washer and the modified restrictor or new set screw whichever you have.
24. The cup washer should be facing up to cradle the spring (cup side up flat side down)
25. Carefully place this assembly back in the slide. Tighten a modified restrictor with a 10mm socket or the new set screw with a 4mm Allen wrench
26. This is a little scary and you do not want to drop anything here, but I have fingers like bratwurst and if I can do it anyone can.
27. Once in place you may pull the slide up with your fingers to help you get started screwing this back in. The angle of the top of the slide and angel the screw goes back in are not 90 degrees, it looks like it could be easy to get cross threaded, take you time here. Tighten
28. Look at the underside of you carb top make sure the rubber gasket is in place. See the shiny spot in the middle? That is where the restrictor kept banging into the carb top when you were kicking your mule to go faster.
29. Put the top back on using the 3mm Allen screws
30. Put the tank back on, reconnect the fuel line, turn the petcock on, check for leaks
31. When replacing the shrouds start the bottom bolts first they are the trickiest. Loosely start all four per side before you tighten them.
32. Put your seat back on.
33. Viola More HP
Scott
, Iv'e got to try it out. It is getting dark here soon :thumbup:
