My poor 525 is leaking a bit of oil from behind the front sprocket. Its not alot, but I HATE oil leaks because so much dust sticks to them and makes a mess.
I'm assuming I hurt the seal when i broke the front sprocket bolt off, and had to heat the bolt to break the loc-tite.
What is involved in fixing this leak?
Hopefully its a seal that can be replaced from the outside........
if you did not roach the bearing it can be fixed from the outside. in fact the leak is pretty common and happens alot when guys run non ktm front sprockets. the aftermarket sprockets are sometimes a bit thinner than the factory ones are. the two big items that go bad or wear out is the cupped washer #22 and the little rubber o-ring #25 that is behind the sleeve #18.
the leak happens because there is not enough force being applied by the thinner sprocket + the cupped washer looses it tension and both can cause a leak to happen. like i said, its very common on the dirt bikes.
i would just order everything and replace them all because of the heat you applied. if you need a different sprocket than what came on it from the factory, just make sure to use a ktm sprocket or one that you know is made to the same specs for thickness.
you are gonna want to order .... 18, 20, 22, 25, 32. if you are careful you can get a small screw into the lip of the seal and pry it out. be careful to not nick the aluminum race that the seal sits on as it can leak if you mess it up. take you time and work from the inside out and you will get it to pop out with no damage done to the motor.
year 2009
model 525 xc atv
part transmission ii - countershaft
The machine shop that removed the broken bolt did NOT put that cupped washer back on, because they used a bolt they had in stock n a different combo of washers. I'll try just getting the right bolt m washer first. I am running a renthal sprocket but I ran it on my 07 with no issues.
Bob, would you suggest that I get the JUNK ktm sprocket bolt too? That bolt is scary soft, and wants to break always. My machine shop used a harder bolt, so it doesn't want to break off. I'll go look and see, as I know they used a lock washer just for good measures to keep the bolt from backing out. I might even still have that sprocket bolt washer, and if so, its going back on!
Ok, I just looked, I have a new KTM bolt, and 2 washers.
I'll install the bolt and washer with BLUE locktite and the new cupped washer tomorrow, and see how it goes.
Glad I had the stuff laying around.
I don't know if I would use a second added on washer in this application Brent.
The cupped washer ( The factory calls it a spring washer ) works with the gear thickness to give the proper amount of side pressure on the o-ring to seal the oil in. If you add the second washer you could be putting too much pressure on the KTM washer which would transfer to the o-ring and might compress it too much.
I see no problem with running a better quality sprocket bolt though. As long as its the correct length and has the same profile on the back side of the bolt as the stock one does. Thats gonna be the tricky part.
If you look the stock bolt has a machined raised surface that matches the cupped washer, they kinda lock together to only allow so much pressure on the sprocket from the spring ( cupped ) washer.
If you look at it, it will be clear how it works.
If it were me, I would buy a new factory bolt and washer and other stuff I pointed out in my first post. Clean out and run a tap thru the output shaft to get rid of all the old loctite and then just use the stock stuff with a good dose of loctite and let it sit for a day to fully cure and then be on your way. Thats what I do and its worked fine for 3 years now.
Like I said before, guys over on KTM talk have had this same thing happen to them many times when they use different aftermarket parts and stuff. Most every time when some one re-does it like the factory, using factory parts, their oil leak goes away.
So, flat side OUT on sprocket is the correct way right?
The sprocket was on backwards, and the cupped washer was not there, so i'm sure this will likely cure my leak.
I believe that the sprocket can go on in either direction. As long as it is touching the cupped washer correctly and the spacer correctly it should not matter.
is matters with the chain allignment. If I run it the other way, then the sprocket ends up closer to the motor, and the cupped washer really doesn't sit well on that shoulder on the sprocket. Its on according to the shop manual. Glad I found my 2nd shop manual, the first one that I Pirated from my dealership was completely BLANK in the engine section. It had all the bullets, and pictures, but all the words were missing! No wonder I never could figure out any of the engine related stuff.
Buy stock or oem parts. Shoulder facing engine, flare side out. Always buy new bolt (use semi-hard lock tote) and cupped or concave spring washer. Use impact wrench set to proper torque. Do this and it will not leak.
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