magneto crankase seal

blckwlfny1 · Apr 4, 2011

Thanks guys. Does anyone know how much of a seal I should expect from the seals at the magneto case.
I recently decided to clean out the crank case from any possible offending manufacturing debris. After thouroughly washing out the warm soapy water I used "water displacer #40" (WD-40) for its intended purpose sloshed it around the lower and poured the extra out. When I later pulled off the magneto cover, I found a film of WD-40 in there. Does this necessarily mean the seal is bad and will not do what its supposed to? I don't want to go screwing with the crank or the magneto unless I absolutely have to as it could throw some other thing out of whack.

Goat Herder · Apr 4, 2011

I used WD in auto repair on seals of all kinds for years O rings on A/C jobs etc. You will be fine.

Goat Herder · Apr 4, 2011

Having the magneto totally hosed with WD I don't think is good tho. Seal off your wires going into the cover with RTV gasket maker silicone and use your magneto cover/gasket with mabbe a thin layer so moisture does not get in. I always prepped my surfaces clean for the gasket maker with brake cleaner. Comes in a spray can with a straw.

2door · Apr 4, 2011

Is this a new, never been run engine? Did you apply compressed air to the crankcase when you were cleaning? The seal should have held back the WD-40 if it was just "sloshed" around but if you used air you could have forced it past the seal lip.
If this is an older engine with some run time on it, now might be a good time to replace the crankshaft seals anyway. Get back to us with a little more information, please.
Tom

Goat Herder · Apr 4, 2011

While admittingly I will use a light coat of say ''axle grease'' [a heavier film of oil] on the lip of the seal when installing a crank or axle seal on a car or any engine etc. My point is the WD will not eat the rubber. I used it on countless A/C jobs with the O rings and on O rings to water pumps.

I think what two door is asking is did you wash out the seal?

When I first got into A/C work I used mineral oil. As the years went by and I floated through different shops I found out WD was a perfectly and widely accepted practice.

2door · Apr 4, 2011

Right, Goat. I wasn't saying that WD would hurt the seal. I was just curious if he had applied some air pressure to the inside of the crankcase when he was cleaning.
I've also used WD as a prelube on lip seals as well as whatever liquid it was supposed to seal against.
Tom

blckwlfny1 · Apr 4, 2011

nope, no compressed air only enough force to squirt soapy water from a dish soap container. engine has about 50 miles on it.
if i pull the magnet, im worried i may screw something else up. i know that these motors are held together with spit and luck
i was also concerned about screwing up the timing.
what is needed to fix that seal?
if i wait, can it be done without pulling the motor off the bike?

rohmell · Apr 5, 2011

You might want to look at replacing/upgrading the crankshaft bearings with something like a 6202-2RS.
These have a rubber seal on both sides of the bearing and give a helping hand to seal the crankcase along with the regular seal.

2door · Apr 5, 2011

rohmell said:
You might want to look at replacing/upgrading the crankshaft bearings with something like a 6202-2RS.
These have a rubber seal on both sides of the bearing and give a helping hand to seal the crankcase along with the regular seal.
View attachment 34956

Rohmell,
I'm just curious. Are you leaving the plastic/rubber bearing seal in place on the inside facing side of the bearing? If so, how long have you run them that way?
Tom

rohmell · Apr 5, 2011

2door said:
Rohmell,
I'm just curious. Are you leaving the plastic/rubber bearing seal in place on the inside facing side of the bearing? If so, how long have you run them that way?
Tom

I am using it it without the seal on the inside, thinking that the air/fuel mixture needs to hit the bearing for cooling/lubrication, have had no problems with the engine for about a year now, mileage wise I figure around 4500.

2door · Apr 5, 2011

rohmell said:
I am using it it without the seal on the inside, thinking that the air/fuel mixture needs to hit the bearing for cooling/lubrication, have had no problems with the engine for about a year now, mileage wise I figure around 4500.

LOL, that's what I was hoping you'd say.

Thanks for posting the bearing numbers.
Tom

Goat Herder · Apr 5, 2011

With that type of sealed bearing. I speculate the lips on the outside seal get's a lot less natural oil lube from the fuel oil/gas mix.

rohmell · Apr 5, 2011

Goat Herder said:
With that type of sealed bearing. I speculate the lips on the seal get's a lot less natural oil lube from the fuel oil/gas mix.

Yes, you are right, but the rubber seal pops off easily, and then it is the same exposed bearing as the original type. The seal that faces outward away from the engine remains intact, and probably acts as a 'helper' seal to the regular crankshaft seal that is on the engine.

Here's a video I found showing a similar bearing and how the rubber seal can be removed and installed:
http://www.youtube.com/watch?v=GgbWhXc6_SE

Goat Herder · Apr 5, 2011

rohmell said:
Yes, you are right, but the rubber seal pops off easily, and then it is the same exposed bearing as the original type. The seal that faces outward away from the engine remains intact, and probably acts as a 'helper' seal to the regular crankshaft seal that is on the engine.

Here's a video I found showing a similar bearing and how the rubber seal can be removed and installed:
http://www.youtube.com/watch?v=GgbWhXc6_SE

My speculation is that the helper seal starves lube from the original seal.

blckwlfny1 · Apr 6, 2011

Does anyone know if there is there a better quality replacement. i dont want to replace the seal with the same piece that leaks just as much

blckwlfny1 · Apr 6, 2011

rohmell said:
You might want to look at replacing/upgrading the crankshaft bearings with something like a 6202-2RS.
These have a rubber seal on both sides of the bearing and give a helping hand to seal the crankcase along with the regular seal.
View attachment 34956

if this is a steel bearing, wont that screw up the magneto? besides, i really am NOT a fan of splitting the motor open at this point

blckwlfny1 · Apr 6, 2011

Nougat said:
17x29x5 from Motion Industries worked for me.

spoke to motion industries which is about 20 min from where i work.
i am sorry to say that not only were they curt and unwilling to answer any of my questions, they said i would have to order a minimum of one dozen of these things in order to get them. if theyre the only option ill spring for it but...well y'know

breno · Apr 9, 2011

Goat Herder said:
My speculation is that the helper seal starves lube from the original seal.

Thats a solid arguement bud.. didnt think of that one.
I too am running the sed set up Ill post up any premmy wearouts.

rohmell · Apr 9, 2011

Goat Herder said:
My speculation is that the helper seal starves lube from the original seal.

It's not a hermetic seal, I am sure that lube can seep past the bearing seal and lubricate the original seal.
One year ~4500 miles, still sealing good here.

rohmell · Apr 9, 2011

blckwlfny1 said:
if this is a steel bearing, wont that screw up the magneto? besides, i really am NOT a fan of splitting the motor open at this point

Nope, doesn't screw up the magneto. The original bearing is steel as well.

magneto crankase seal

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