Front Sprocket / oil leak question

[Danny T]

Hello everyone,

So when i went to go ride yesterday my bolt that holds the front sprocket some how came off! when i turned on the bike i noticed oil leaking majorly.

Is this because i have nothing holding the sprocket down tight or do i have a bigger issue and this is normal when the sporcket is not locked down...

THANKS!

[Peelz]

the sprocket nut came off?  Yikes....

Sprocket does not hold that tight. Probably something else happening.

[Krandall]

My guess is the seal that  goes between the case and sprocket is toast.

Not sure how hard they are to replace, but here it is. #40 I'm guessing.
http://www.yamahaoftroy.com/fiche_section_detail.asp?section=675542&category=ATVs&make=Yamaha&year=2007&fveh=17978

[Danny T]

hmm how should i go about diagnosing this. should i just replace the nut and washer and see if it leaks? or take a different route?

[Alkire193]

Dig in and change the seal, and take a look at the grooved collar inside there just be sure it doesnt have some damage to it. Im not sure if you have to split the case to get at the seal but its possible

[Danny T]

Dig in and change the seal, and take a look at the grooved collar inside there just be sure it doesnt have some damage to it. Im not sure if you have to split the case to get at the seal but its possible

well i ordered that seal, but im going to try and just put that nut back on, throw some loctite on there and see how she goes. hopefully i dont need to change it bc im pretty sure the case will need to be split and i am not capable of that!

[09RappySE]

If you have oil leaking past the output shaft, your oil seal is toast it has nothing to do with the sproket bolts, they just hold the lock collar in place so your sproket does not come off. I would not think it would be that difficult to change...once you remove the old seal the new one should press in, you will have to be carefull not to damage the seal on installation.

[Danny T]

ok so i took off the plate cover and collar and see the rubber seal. Should i just pull this thing out with a needle nose plyers? anything i should know when inserting the new seal? Thanks again!

[Danny T]

oh and i forgot to mention. there was NEVER a leak prior to the sprocket BOLT coming loose/off.

[Alkire193]

Can I get a pic of said leak? A nice close up?

[Krandall]

+1 for the pic

[Livingmylife93]

I changed the seal that your talking about on a buddies 300ex once, it was a real pain in the ass but it was fun. Case had to split and the gears and everything had to come out...

[Alkire193]

I changed the seal that your talking about on a buddies 300ex once, it was a real pain in the ass but it was fun. Case had to split and the gears and everything had to come out...

I think he has to but im trying to be positive. 

[Livingmylife93]

I changed the seal that your talking about on a buddies 300ex once, it was a real pain in the ass but it was fun. Case had to split and the gears and everything had to come out...

I think he has to but im trying to be positive. 

Well its quite the project, a good time to do more work to the bottem end if $$$ permits. But if you dont have a garage or anything to do it in, briing it to a friends house or something and start working on it! Once you do it, you'll feel alot better about it and be proud that you did it. And you'll learn a hell of alot.

I would do it wether or not cause i dont have the moiney to bring it to the deal. or i might just leave it....

Just my 2 cents 

[09RappySE]

If it was leaking bad enough that it had to be fixed, I would remove the old seal with a scribe, clean up the area and attempt to press in a new seal, the seal has to press in from the outside of the case, I would just make me some kind of insertion tool that will fit over the outout shaft and allow you to press the new seal flush with the case. Just apply plenty of oil to the seal first, this may not work....but if it does, it beats splitting the case.