Counter-Shaft (c/s) Seal FAQ (2nd Draft)
compiled & edited by Kristian #562
by Flash #412 & Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.
June '02
What is the Countershaft Seal and Where is it.?
It's just a normal Oil Seal which seals the Engine Oil (Gearbox) from coming out past the Countershaft, which is the Shaft, with splines, that your small front Sprocket is mounted on.
What are the Symptoms of Seal Failure.?
Oil Dripping down from underneath your sprocket and getting all over the bottom of your bike and around the c/s Sprocket area. Very messy. When you get the Sprocket off it might look like this:
The BMW Part Number for the Seal is 11 11 2 343 018 (Both F650GS & Classic).
On the OEM Seal is stamped: FPJ 25 40 7, then GS, then ACS in very small letters, then C18.
But you can just go to your Bearing and Seal shop and buy an ordinary 25 X 40 X 7 Seal. It will work as good if not better. My (new) one stamped ERIKS, RST, 25 40 7, 1.
243 Loctite or Equivalent for the Nut
'97 Classics and above, GS/Dakar. 1 Lock-Washer ; (You may be able to reuse the old ones if still in good condition. For the price though, go with a new one).
'96 Classics and older, a new Circlip, but get the RIGHT one. Refer the Internal/External Snap Rings FAQ before proceeding.!
You will need:
Torx Keys or Allen Keys in your Toolkit for loosening Chain
Adjustors & removing the Plastic Sprocket Cover Plate
Sockets/Spanners for Rear Wheel Axle Slackening.
30mm Socket for the Counter Shaft NUT, preferably using a LONG handled Wrench.
Torque Wrench to 100Nm.
A Small drill, hand operated is MUCH preferred, you can control it much better than an electric one, and it is not slow if you have a good drill bit.
One or Two Sheet Metal Screws.
Countershaft Seal Replacement
It should be no big deal to replace the countershaft seal.
Put the Bike on the Centrestand.
Take the counter/shaft sprocket cover off (The one Stamped "BMW"). There are 3 Allen Bolts. You have to depress the brake pedal to get the last of the three bolts loose and to remove the cover. Set it aside.
First Remove the countershaft nut using a 30mm socket. This may require a long handled wrench to provide the necessary leverage for stubborn bolts. The nut unscrews counter-clockwise.
The whole c/s Sprocket will try and turn if is not held by something, so to stop it turning you can either:
Put the bike IN 1st GEAR. This will hold it via the Engine Resistance. This is easiest and should work most of the time.
Place one foot on the Rear Brake to hold the Rear Wheel in place. (You can also put it in gear AND stand on the Rear Brake.!).
Follow the Manual and unscrew the Plastic Centre Plug in the RHS Engine (Alternator) Housing, insert an Allen-Key Socket into the CRANK which sticks THROUGH the flywheel and hold the Wrench while you undo the nut. It doesn't NEED to be a socket. A standard Allen and piece of pipe will do just fine, as long is it isn't the weak tool from the stock toolkit.
You can also use the (TDC) crank-stop bolt if it is in gear and not muck with the brake at all, if you happen to have a crank stop bolt handy. It's a small bolt BUT, it hardly sticks through the case at all before it goes into the slit in the crank. Here's a picture of the split cases and how the bolt stops the crank. Besides that, when you reef on the c/s nut, you have mechanical disadvantage through the transmission to the crank. In first gear, you have the INVERSE of the advantage the motor has over the rear wheel (less the c/s - final drive ratio). So 100 Nm is reduced by a factor of 7 or something, which means you really aren't reefing on the crank stop bolt. When you take the clutch basket out, that nut is nearly at the same torque. And the ONLY way to stop the crank then is via the crank stop bolt. Again, you have the disadvantage of the primary drive gear ratio in your "favor" (to keep from snapping the bolt).
Loosen the Main Axle Bolt.
Set the wheel toward the front of the adjustment range (a couple notches back from full forward) with the Chain Tension Adjustment Bolts. i.e. Loosen the bolts and PUSH the wheel forward as far it will go. Refer the Rear Wheel Removal FAQ, for further details, but you do not have to remove the wheel, just push it as far forward as possible to slacken the chain.
Thread the Chain off the front Sprocket.
Remove the front (c/s) sprocket. Remove the O-Ring, if there is one. The seal will be exposed.
Drill a small SHALLOW hole in the old seal and screw a #6 or #8 sheet metal screw in there a couple of turns (the idea of the hole and the screw is NOT to go so deep as to touch the bearing) and then pull the old seal out with vise grips. Or, if you have a tiny prybar that works, forget the drill & screw and just pry it out.
Sometimes on a large or difficult seal, use 2-3 screws to get it out cleanly.
The clearance behind the c/s seal, between it and the bearing, is about 3-4mm so you have a bit of room for your screw to go in. BUT note, because of this it is possible to push this seal further in than the OEM Seal was. The only way to get it out is...you guessed it, drill a hole. You will need a new seal though.! I don't think it is a huge problem running the seal a bit further in if you happen to do this by mistake. You can always run it for 12,000 -15,000 miles until you change the Sprockets next.
Drive a new seal in with a deep well socket or properly sized piece of plumbing and you're done. Push it in so it is flush with the face of the Engine Casing.
Follow the Procedure in the Chain Replacement FAQ for putting everything back together.
Don't forget to apply Loctite to the countershaft threads before you re-install the nut.
Comments:
It should be no big deal to replace the countershaft seal. Remove the sprocket. Drill a small SHALLOW hole in the old seal and screw a #6 or #8 sheet metal screw in there a couple of turns (the idea of the hole and the screw is NOT to go so deep as to touch the bearing) and then pull the old seal out with vise grips. Or, if you have a tiny prybar that works, forget the drill & screw and just pry it out. Drive a new one in with a deep well socket or properly sized piece of plumbing and you're done. Also, if you overfill the bike, one of the places oil gets into is the alternator housing. It then gets blown out through the wiring seals, (behind the small metal plate). From there it can either run out over your right foot, or back down the top of the front sprocket cover. There's no problem with a little leakage past the countershaft seal anyway, you just save yourself the cost of a Scottoiler. Flash #412
Mine failed and the dude across the street fixed it no fuss no muss, in the way flash describes. It's BMW part # 11 11 2 343 018 (for the classic Funduro). Cost $4.99. NormJ #473 Seattle. (Note ANY seal Shop will have that Seal. ed.)
OK,
here's something puzzling for you gurus. I changed the c/s Seal on the w/e as
you know and took the opportunity to change the Oil too. I think the previous
owner had overfilled it, as I put in the requisite 2.3l and it comes 1/2 way
up the sight glass. 5w50, although I don't need the 5, the 50 end helps in
summer here. Now this morning I took it for it's first full run since and when
I got here there was oil coming out of the small Clutch Actuator Arm Seal on
top of LH Engine Housing. If one of the oil circuits got blocked, could that
force a bunch of oil into the Clutch housing or is it just the New Oil is
Sealing the Rings so well it is pressurising the Crankcase. Reckon I should
change the Seal or wait and see? Kristian #562
