Starter Shaft seals leak !!

7 replies to this topic
  • dubious

Posted January 23, 2004 - 10:00 PM


Upon removing my starter cover to inspect the gears I found a considerable amount of moisture around the starter shaft and gears.
I have been riding my bike in the snow quite a bit and beleive that the warm engine has been drawing moisture past the seal or that the moisture is condensation from the engine being hot in cold climates. The same problem could occur when crossing deep water and the engine is hot, sucking water past the seal and into the engine contaminating the oil.
Looking at the oil passage / gearway it appears that heat and condensation could be trapped up at the starter where it enters the side case, as the oil travels upward on the gears and any heat or moisture may be trapped up there, and could theoretically drain back into the enginr oil after allowing the engine to cool.
Either way I am not to impressed to see moisture mixing with my engine oil.
Just thought I'd mention my findings so you could all keep en eye on your machines!

damn Yamaha and their aftertought for a starter :)

  • Indy_WR450

Posted January 24, 2004 - 05:58 AM


You can replace the O-ring seal and even put silicone gasket material since the part that is protecting the starter motor gear does not rotate.

  • VB_Racing

Posted January 24, 2004 - 06:33 AM


It is not unusual for the engine to have alot of moisture in it, if you are riding in the cold. All internal combustion 4 cycle engines will hold moisture inside the engine, and even in the oil, because of the constant heating and cooling of the motor. The moisture will evaporate the next time the bike heats up, and will reappear as it cools down. With the temps up here( -10 to 10 degrees for highs!!)I see great amounts of moisture in the crankcases of every car that comes in for service. ( I am an automotive technician). And remember on modern cars that the crankcase is for the most part kept free from pressure, and sealed for emissions reasons. Our bikes have no PCV sytem, just a simple crankcase vent, and will easily get cool air into the crankcase causing ALOT of condensation. My bike gets the oil changed after every ice racing weekend, because of the constant heat cycling. The reason you see the moisture in the starter drive area is because when the water heats up and evaporates , it gets caught in the highest point of the cover, not because the starter o ring may seep a little. Remember you have a big hose that will let air in the crankcase, but it is in the valve cover, and anything trapped in the top of the starter drive housing will not get to the top of the engine.
I guess to make a long story short is, don't worry about that little bit of moisture, it will "steam" out when the engine gets warm again, and make sure to be regular about the oil changes.


  • dubious

Posted January 25, 2004 - 01:46 AM


Yeah I'm with both of you. I realize the moisture cause and collection and how to alleviate the problem. :D
It's just disturbing.

Thought I would share my findings and make everyone aware!
If your engine is hot and you run it under cold water, there is a very likely possibility of water being sucked into the sump past the one wimpy o ring sealing the engine/starter. :)

You'd think they would have used a double lipped seal like a countershaft seal or something. :D

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  • Indy_WR450

Posted January 25, 2004 - 07:10 AM


I put a little silicone gasket sealant around mine when I did the 04 starter upgrade. Changing the oil a lot every 2nd ride should take care of this issue unless you are truely driving all day in 2 feet of water I would not even worry about it. :)

  • dubious

Posted January 25, 2004 - 08:07 PM


hey indy, how do you like the magura clutch? :)

I was contemplating a purchase but have not seen one first hand or gotten to check the lever pressure. :D
Ever since I played with EVERTS WORKS CLUTCH at the bike show I want one.
I think his was soooooo light because the slave cylinder was massive - like 2" in diameter thus vastly reducing the pressure needed to apply it,- the haudrailic fluid has so much surface area to apply pressure to that the lever pull was incredibly light.
The brand new KTM 525 clutch I checked out had lever pressue about 5 times what everts was!
Actually Everts slave cylinder looked like something similar to what you'd find on a liter sport bike.
I don't use my clutch much locally but when I go riding in the mountains in B.C. its mostly all really knarly 1st gear, slipping the clutch, handlebar wide slimy root and log infested single track.
:D :D :D

  • Indy_WR450

Posted January 25, 2004 - 08:20 PM


No problems with the magura jack clutch. I keep hearing complaints but with a good install and SS braided line it is so smooooooth and light! I love it. I designed my own pivoting mount for the end of the slave cylinder and my own mounting bracket to space the slave cylinder above the starter motor. I hear this is where there can be issues. The slave cylinder alignment mount and rod end binding can create failures. I have the design prints and can have parts made for other TT members that want better. In a nut shell it is a great product with weak engineering in mounting design from model to model. :) PM me with your email address if you want detailed photo or design or I can have parts made for active TT members.

  • dubious

Posted January 25, 2004 - 10:06 PM


Indy that sounds great. I'll check out the prices and PM you if/when I decide what I'm going to do!
Thanks! :) :D :D


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