In this post, I’ll be showing you how to replace and adjust the throttle cable on a two-stroke dirtbike. Alright, so today I’m going to be showing you how to replace the throttle cable on a 2004 YZ250 two-stroke. Now this bike here has a single cable that operates the throttle. Now there are several other bikes out there that use a dual cable system as a lot of the modern four-strokes.
So if you have one of these that needs some help with replacing it, see our four-stroke throttle cable replacement video for some help with that. Now after some time and use, your throttle may become a little sticky and doesn’t exactly return to the full close position very smoothly or quickly.
Now if this is the case, you either need to do maintenance or replace it. So after having twisted your throttle through all of your adventures, the sheathing inside of the throttle cable which helps it to operate smoothly it may begin to wear out making the throttle’s operation not so smooth anymore.
So when it comes to determining what’s going on with your throttle, there are a few things that could be at play. It could be the throttle cables routing, could be the throttle cables adjustment, the throttle housing itself or the throttle tube. Now, you can just replace the cable and that’s generally a good idea because they’re relatively inexpensive and easy to do.
Now today we’re going to go through and show you how to install the throttle cable, how to maintain it, adjust it and what to look for if you’re having a not so fun experience when it comes to twisting your throttle. To do this job you’re just going to need a few basic hand tools, you’ll need some cable lube as well as some safety glasses. Now we offer several different brands of throttle cables.
For now, we’re going to be using the Tusk Replacement Throttle Cable, and as always before beginning any procedure on your motorcycle be sure to reference your service manual for those proper procedures and torque specs.
Alright, to begin you’re going to start by getting access to the throttle cable so we’re going to pull the seat and then the gas tank. Next, we need to remove the carburetor’s slide that the throttle cable is attached to. Now to do that, we need to gain access to these two screws that on the top of the carburetor. Now to do that, we need to loosen these clamps right here so that we can rotate the carburetor towards us to gain access.
Okay, so now that we’ve got these two screws removed, we can pull this cover-up and we can pull out the throttle slide. Now, to get the cable out of the slide, we need to pull the spring up then we need to grip the throttle cable as high as we can right here like so. So we’ll take and push this slide up and out and the cable will come out. At the end of the cable here, there’s this larger end and this will set inside of the center part of the slide here which it’s able to grip.
So I’ll pull this off, we’ll pull our spring and then we need to remove the threaded apart of the cable from the cap, so undo the locknut and unthread it. Alright, so once you get this top part removed from the cable, we can move up to the top side and start working on the throttle housing. Alright, so we’re up here topside at the throttle housing assembly.
Now, to remove the cable, we’re going to start by pulling off this rubber cover and then on the throttle housing itself, we’ve got an additional rubber casing, so we’re going to work this off and peel it back so that we can expose these two screws. We’ll pull these two screws and remove this cover. So now that we’ve got the cover removed, we can remove the throttle cable. So to do this, we’re going to slide the cable like so, twist the throttle then we can grab the cable and pull it back up then we’ll work it out of the throttle tube.
Alright, so once you get the cable worked out of the throttle tube, you’re going to want to pull this pulley right here. Now this pulley has a collar on the inside of it that this rotates around, you want to make sure to not lose this. Next, we can start to remove the throttle cable from the housing. Now to do that, we’re going to take a 12-millimeter box open-end wrench, we need to crack free the locknut and then we can unthread the throttle cable up here and pull it out.
Alright, so now we’ve got our throttle cable removed from the housing, you can see how this is installed here. We’ve got a little channel that opens which allows for us to insert the throttle cable and then thread in this upper part of it, so that’s how that comes apart. Alright, so now that we’ve got the throttle cable disconnected from the bike, we can now remove it.
So you want to pay attention to how the cable is routed so that when you install the new one, you can install just like the old one. Now you may have some additional cables that secure the throttle cable to the bike, so make sure to get those loose or pull them free. Now I’ll also be inspecting your cable routing to make that you’re not bending around any extreme angles.
If it’s bending around some really extreme angles that’s going to create some extra resistance when it comes to operating your throttle. Now we can take and thread the throttle cable back through the same routing as it was removed from.
Now if you have any question as to how your cable is to be routed, be sure to reference your service manual for that specific information. And again when you’re routing the cable, make sure that it isn’t experiencing any significant or extreme bends. Okay, it looks like we are there. Now before we get this installed on the rest of the bike, we’re going to lube the cable before we put it into use.
So for this, we’ll be using the Tusk Cable Luber, a really great tool, easy to use. Now a couple of things you’ll notice about it, on one side you’ve got a larger opening and on the other, we’ve got a very small opening just enough room for a throttle cable. Now, we’re going to set this onto the throttle cable like so, and then we’re going to tighten it up.
Once you’ve got that nice and tight, you can take your cable lube and put the nozzle inside the insert. Now when applying some cable lube, just give it a few quick squirts, and then work the cable back and forth to work the lube down to the bottom of the cable. Now you want to move this up enough so that the base of throttle cable you’ll start to see some of the cable lube come out the bottom.
Now before installing the throttle cable into the throttle housing, make sure to remove the housing, clean the handlebar and inner part of the throttle tube, inspect the throttle housing and pulley, make sure it is clean and clear of dirt and debris and then the lube with lithium soap base grease or equivalent after having cleaned the housing. Now it wouldn’t even hurt to apply just a little bit of cable lube to where your throttle attaches to the handlebar.
Now be sure to have some clearance between the end of your handlebar and the very end of the throttle tube. If there is no clearance here, your throttle may stick. Now after you’ve cleaned your throttle housing and the associated parts, go ahead and get it reinstalled. Next, you can take and install your throttle cable, so for this bike, we’re going to be inserting it in through the rubber cover here, and then into the throttle housing.
Alright, now as we thread the throttle cable into the housing, you’ll notice that the threads’ length exceeds the length of what’s allowed to be inserted. Now, we don’t want to set the threads to come pass where it’s allowed or else it will interfere with the pulley that sits in this location. So be sure to stop threading in your throttle cable before it reaches the spot where it can make contact with the pulley, so at this point, we’ll set the locknut.
Next, we can place the throttle housing’s pulled into the housing. Now you’ll notice that this is indexed so on the top here it states that this is the upper side the top side so make sure you put that in the right way. So now that we’ve got that inside of there, we can lever it out just slightly, loop the throttle cable around it and then we can attach it to the throttle tube.
Alright, now once you’ve got your cable installed with the pulley, be sure to reference your service manual for the proper procedures and the lubricants that it recommends that you use. Now the last thing to do is install the cover. We’ll button up the top part of the throttle here and then we’ll move back down toward the carburetor and get it installed on that slide.
Now we can thread the bottom side of the throttle’s cable onto the carburetor’s cap. Once that’s in place, we can reassemble the spring and attach the slide. Alright, so once you get the slide reattached to the throttle’s cable with the spring, we can install it into the carburetor. Alright, so once you get the cap to sit back on to the carburetor, we’re going to rotate the carb so it’s back in its upright position and then we’ll secure the clamps.
Alright, so now we’re back up here the top side of the bike and we’re going to check for throttle free play. So what’s that free play is, is we want some movement in the throttle tube without it actually operating the throttle. So you want to check this with the handlebars, full clock to the right and full clock to the left. You want to make sure that you have about 3 to 5 millimeters of free play.
Then the next thing you want to check for is you have a smooth operation at full clock right and that the throttle snaps back to the closed position, check this full clock right and full clock left. Also, double-check your throttle cables routing, make sure that it’s routed correctly. If you have any doubts make sure to refer to your service manual for that specific information.