Oil leaking from drive sproket on atc 90?

[Wayne_Hill]

On my atc90 project it leaks oil from what lloks to be where the drive sprocket goes into the engine. What is rong with it? Is the seal gone? Would a new complete engine gasket kit solve the problem?

[90nut]

Does the oil only come out of there when it is running? Mine comes out behind the front sprocket when it is running but it dosent when it's not running. I don't know if this is like a oil slinger type thing to lube the chain or if my engine is just messed up.

[ric]

Most probably you have had a chain come off in the past and punched a hole in the crankcase, very common problem with atc90s, well. used to be common when ATC90s were all you could buy, it happened to a couple of mine. you have to split the engine, thats a big job, get the left side case welded back up, reface the casing and reasemble the whole lot. might be a good to for a full rebuild.
But then again, could just be a leaky seal. I've got my money on the busted case but for you sake I hope its just a seal.

[atczack]

I'm pretty sure you can pop the old seal out and rub a light coat of oil on the new one and pop it in from the outside of the motor, just take the countershaft sprocket off. I would attempt this first being that it will only cost a couple of buck's for a new seal probably. It's worth a shot.

[MTS]

I'm pretty sure you can pop the old seal out and rub a light coat of oil on the new one and pop it in from the outside of the motor, just take the countershaft sprocket off. I would attempt this first being that it will only cost a couple of buck's for a new seal probably. It's worth a shot.
you cant take the countershaft sproket off unless you take the hi-low selector off and and take the left side case off

[thefox]

Clean up all around the output shaft and see where it is coming from. Chances are the seal is worn out. You can remove the front sprocket and pull out the seal and put in a new one fairly easily. Oil seals do not come in gasket kits, you would have to get a single seal from your honda dealer or find a seal kit (im not sure if there is one for the atc 90).

[atczack]

Daaaaanggg!!! Sorry about the misinformation, is there any other model's like that?

[a-camp]

Ya my chain saw does thet too.lol

[ric]

seal on the sub transmission side is 91202-053-000 (31x43x8), seal on the engine side is 91201-053-000 (27x37x7).
You will need a flywheel puller as the flywheel has to come off along with the sub-transmission to allow the outer casing to be removed to gain access to that seal, be carefull not to damage the output shaft or the casing when removing and replacing the seal.
Hope it cures your problem (but I got me doubts!)

[Howdy]

Most probably you have had a chain come off in the past and punched a hole in the crankcase, very common problem with atc90s, well. used to be common when ATC90s were all you could buy, it happened to a couple of mine. you have to split the engine, thats a big job, get the left side case welded back up, reface the casing and reasemble the whole lot. might be a good to for a full rebuild.
But then again, could just be a leaky seal. I've got my money on the busted case but for you sake I hope its just a seal.

I have been working on these machines for well over 16 years and I have seen a lot of oil leaks ( like has been mentioned above ) on atc90, atc110, and atc125m's. I can only remember a couple that were from the seal being bad. So speaking from experiance I will put my money on a broken case also. To fix it correctly you will need to have the case welded and machined. To have someone else do this for you can be costly. When i run into this problem I just swap the bottomend out with a good one ( I have a lot of these motors ).




I'm pretty sure you can pop the old seal out and rub a light coat of oil on the new one and pop it in from the outside of the motor, just take the countershaft sprocket off. I would attempt this first being that it will only cost a couple of buck's for a new seal probably. It's worth a shot.


you cant take the countershaft sproket off unless you take the hi-low selector off and and take the left side case off

I know of one atc90 motor that you could just pop the seal out and replace it ( see attatched pictures ). But then this 1974 atc90 motor ( actually the whole machine ) has been heavily modified. What is it and Where did I get it? I won't say right now ( I am waiting on some things to get here ).
Howdy

[HaggLE]

Ive got one of those 90 motors without the hi-lo range. You arent that special. I use it in the aluminium frame 70 that i posted pictures of around a week ago.

[MTS]

ohhhh Howdys got a new toy!!! i want one :naughty: :w00t:

[Billy Golightly]

HaggLE, No offense, but I know what that motor goes to and I really doubt you have a trike as special as it ;) You will have to hang around to see it, but I can assure you, you wont be dissapointed.

[HaggLE]

HaggLE, No offense, but I know what that motor goes to and I really doubt you have a trike as special as it ;) You will have to hang around to see it, but I can assure you, you wont be dissapointed.

I never said that it wasnt special, i said that he wasnt that special because i have one as well.

The antisipation is killing me, can you tell us a bit more about this trike?

[Billy Golightly]

lol, I wish it were my place to. I will say however, that it is VERY special :D

[atczack]

Sweet howdy, can't wait to see it all together.

[Wayne_Hill]

Does the oil only come out of there when it is running? Mine comes out behind the front sprocket when it is running but it dosent when it's not running. I don't know if this is like a oil slinger type thing to lube the chain or if my engine is just messed up.
Yes, it only leaks when it is running and maybe a fex minutes after.