2 Stroke Replacing Crank Seals 97 Cr 125

NicholasA

NicholasA

My bike has recently started losing trans oil and running rich and i have diagnosed it a a leaking right crank seal. I have taken it all apart and ordered a new seal, gasket, and drive gear collar from Honda. parts should be here on friday. I am now wondering how deep in the race should the new seal sit. how far in do i need to drive it? the old seal is not pressed very far in but i am wondering if this is just because the seal has failed.
 
bobkyle2

bobkyle2

I'm pretty sure the seal should sit flush with the case....

Be sure to make sure you set that seal in the correct way the old one came out...
 
NicholasA

NicholasA

I have heard hydro locking can force the crank seals out? I don't know if this is relevant to this model, i have also heard pressing the crank seals in too far can starve the main bearings of oil? But I don't know if this is relevant to this model either.... That last one does not make sense to me because they should be lubed by the fuel not the trans oil?
 
NicholasA

NicholasA

So the plot thickens....
Here is a picture of how the seal was when I removed the right side cover
 

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NicholasA

NicholasA

Noticed that the seal is not flush with the cases. I also noticed that that bottom of the seal seemed to be chewed up by something. Here is a picture of the wear on the bottom of the seal
 

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NicholasA

NicholasA

This wear appears to have come from it rubbing aginst the power valve governor gear. But it goes all the way around the seal which means the seal must have been spin in freely and the only way it could have touched the governor gear Is if it popped almost completely out of the cases. Here is a picture of how I think this wear happened
 

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NicholasA

NicholasA

So I am thinking fuel flooded my cases and when I kicked it over it popped the seal out and it spun for awhile on the drive gear collar contacting the gear on the power valve governor? Idk just my current theory? What do you guys think
 
SRAD97750

SRAD97750

Moderator
Staff member
NicholasA:
I don't think This is possible because the governed gear sits between the seal and crank gear
Click to expand...
Yes, same thing. One of the spinning gears came in contact with the seal as it came out of it's seat.
The gear was spinning, not the seal.

I have issues with my clutch cover gasket getting pushed out when my transmission vent hose plugs with dirt. But this is the opposite direction of pressure.... Not sure yet. -BIG DAN:thumb:
 
NicholasA

NicholasA

SRAD97750:
Yes, same thing. One of the spinning gears came in contact with the seal as it came out of it's seat.
The gear was spinning, not the seal.

I have issues with my clutch cover gasket getting pushed out when my transmission vent hose plugs with dirt. But this is the opposite direction of pressure.... Not sure yet. -BIG DAN:thumb:
Click to expand...
I know the seal is not supposed to spin but It must have come almost all of the way out of the crankcase to the point where it was spinning freely on the drive collar The gear and seal had to have been spinning, it's the only way those marks could have been made. I really appreciate the feedback thanks dan
 
M

MikeinFresno

so then, was your motor so flooded with fuel or water from falling in a creek that it was full of liquid to make this possible? Sounds it is a possible way for it to happen, but was your motor full of liquid??
 
NicholasA

NicholasA

MikeinFresno:
so then, was your motor so flooded with fuel or water from falling in a creek that it was full of liquid to make this possible? Sounds it is a possible way for it to happen, but was your motor full of liquid??
Click to expand...
I bought it without a top end so who the hell knows, but I guess it must have been it's the only thing that I can think of that explains this.
 
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