How To Replace A Countershaft Seal On A Dirt Bike

How To Replace A Countershaft Seal On A Dirt Bike

– Hey what’s up guys, Dustin here with Rocky Mountain ATV MC. Today I’ll be showing you how to replace the counter
shaft seal on a dirt bike. The counter shaft seal’s what
keeps the transmission oil from leaking out of the transmission through the counter shaft. Now when it begins to leak, you will definitely be able to notice it as you will see transmission oil in and around the area of
the counter shaft sprocket. Now they’re really easy to change out and today I’ll be showing
you how to service it on a 2015 KTM300XCW. To do this job we’re just
gonna need a few tools, now keep in mind those tools may vary depending on the bike
that you’re working on but for today we’ll be
using some snap ring pliers, we’ve got some open ended
wrenches, a set of pliers, a hammer and a socket that’s
about the same diameter as our oil seal here. Then we’ve got the K
and L oil seal pullers as well as the motion pro
counter shaft seal puller. We will be using the motion pro for today. Then we’ve got the all balls
counter shaft seal kit, that’s a replacement for the bike. Now we do offer many other
options at our website so be sure to check that out. Then we’ve got some rubber
gloves, some grease, contact cleaner, some rags
and some safety glasses. Now when it comes to working on your bike. Always be sure to
reference your service menu for specific procedures,
safety information and torque specs. To begin start by thoroughly spraying down and cleaning the area of
the counter shaft sprocket. Next we can remove our
counter shaft sprocket by either removing your snap
ring, center bolt or nut. If you have a counter shaft
nut, start by using a chisel, punch and hammer to flatten
the lock nut washer. Put the bike into gear to
help freeze the counter shaft, while a buddy holds down the rear brake so that you can remove the nut or bolt. It may be difficult to
remove the sprocket nut but don’t worry, this is totally normal. Then we can begin to remove our sprocket from the counter shaft. Now depending on the type
of the bike that you have, you may have to remove the chain or just create some more slack. With the sprocket removed be sure to clean the area
of the counter shaft seal and remove any dirt and mud or sand. With the area of the counter
shaft nice and clean, we can take our channel lock pliers, we can grab on to the sprocket spacer and we can pull it off he counter shaft. Now we can remove our counter shaft seal. Now for this we’re gonna
be using our motion pro counter shaft seal removal tool. Now you can use a variety of other tools but if you choose to do so, be careful not to scratch the engine case or the counter shaft. Now to use this tool, we’re
gonna hold on to the body of the seal remover, we’re gonna
take a 17 millimeter socket and we’re gonna rotate this like so and this is going to spread
or open the seal puller. Once you’ve got that nice and snug, we’ll keep our 17 in a fixed position and we’ll take our 14 millimeter and we’ll begin to rotate it clockwise and this will begin to press
against the counter shaft in turn removing the seal. With the seal removed we
can now remove the O ring with our pick tool. Then take a clean rag and carefully remove any dirt or debris that may
be trapped inside of here. Be careful not to knock
it into the bearing or into the transmission’s case. I just wanna take a minute
and talk about the O rings that come in this replacement
seal kit for this bike. Now the kit will come with two
different sizes of O rings. So once you get yours removed, you’ll wanna match it up with
an O ring that’s the same size and same diameter. Now once you get that installed, if it is still leak
from the counter shaft, you will want to swap it
out for the other one. Now keep in mind there
are some bikes out there that have two O rings on the counter shaft so be sure to reference
your service manual for your bike’s specifics. Before we install our new O ring, we’re gonna take just
a little bit of grease and coat the O ring. We’re gonna slide it on
to our counter shaft. Next we can take our counter shaft seal, we’re gonna take a little bit of grease and we’re going to coat
the lip of the seal evenly. You can even take a small amount of grease and just kinda coat the
outside of the seal as well. Then we’re gonna place it
on to our counter shaft here like so. Press it into place lightly,
so it’ll stay there, then we can take our socket that’s about the same size
in diameter as our seal and we can begin to drive it into place. Now when we drive the seal into place, we wanna make sure that
we drive it on evenly and then we will set it so that it is flush
with the engine’s case. When driving the seal, take your time and be careful with this
step as to avoid damaging it. Checks to see if it flush
with your fingertips. Before we install the sprocket spacer, there’s something I wanna
point out real quick; the side that’s going to
face in towards the engine will have a lip to it, a slight recess. This is going to
compensate for our O ring. Now the side that’s
gonna be facing outwards will be nice, flat and flush. Now before we install this, we’re going to take just
a little bit of grease, we’re going to coat the outside of it. Once the outer diameter has been coated, we’ll coat the area in which
we’ll mate with out O ring just slightly as well as
a little bit of grease on the inner diameter as well. Then we can take an place
it under our counter shaft with the recessed side facing the engine. Once we get to the seal, we’ll
gently work it into place. Wipe of any excess grease. Then we can reinstall the
sprocket onto the counter shaft. Before installing your sprocket, make sure to give it a good cleaning. Next we can install our snap
ring onto the counter shaft. Now before we do that, we
need to make sure that we have enough clearance on the shaft so that I can receive the snap ring. Now if when you push on your sprocket and your not able to get enough clearance to see the ring landing for the snap ring you may wanna switch over
to the thinner O ring. Once you get your snap ring set into place you’ll wanna double check to make sure that it’s fully
seated in its ring landing. So give it a good inspection. Now if you’re using a center
bolt type or the nut type that bolts on, you’ll wanna
use some medium strength to high strength thread locker. Now with the snap ring style, just to give us some added assurance, we’re gonna take some
silicone gasket and cover the snap ring and the
splines that protrude from it just to ensure that it
doesn’t have a chance of ever coming off especially
in racing conditions. Now if your counter shaft is a nut type, make sure to reinstall the
lock washer but inspect it where it bends over to the nut. Now if it’s cracking or breaking,
make sure to replace it. Then we can install, the
countershaft sprocket nut, place the bike into first gear and have someone hold the foot break while we torque the sprocket nut to spec. Next, bend the locking tabs
over onto the lock nut. And that’s it, replacing the
counter shaft seal is a breeze especially when you have the right tools. Now if you have any questions, feel free to leave us a comment below and we’ll be sure to get
an answer back to you and subscribe to our Youtube channel for more product spotlights,
top fives and tests and also see our website Alright that’s it for me, I’m
Dustin with Rocky Mountain, thanks for watching and
keep turning those wrenches.

About the Author: Michael Flood


  1. Great video, Never had to do this before on my Honda's, Yamaha's or Suzuki's. This must be a repair very specific to KTM.😬

  2. Might be a dumb question but if I had a bad seal, would the sprocket have to be spinning in order to leak? I’ve whipped everything down and let the bike idle for a while and it’s dry as a whistle, do you think I’m good to go?

  3. Instead of using the Motion pro seal remover, will the Tusk bearing remover kit work instead? I already have that kit and won’t want to buy the Motion Pro if I don’t have to. Thanks!

  4. Hi, thanks for this video, excellent as always. I have a 99 KX250, says there's two o-rings, where does the other one go? do i just slide the other one after the first one that's in that groove? I cant seem to find any information even in the service manual. thanks

  5. Could you guys do a video/ show more about that light bar setup? That is totally awesome and I’ve thought of using the Tusk light bar for that.

  6. Rmx450z seal wouldn't come off with tool just ripped seal and seal is stuck on good. Any ideas how to remove seal? Also rmx450z have 2 oring seals.

  7. if you weren't to do that, would it affect the air to gas ratio cause air could make its way in couldnt it? then affect the performance of the bike

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