Spitting trans oil from behind front sprocket

[HoLLo]

I just bought a 98 Yamaha Blaster 200 from a buddy of mine on the cheap who needed some quick cash. He has owned it for several years, and tell me the bottom end has been bored over a bit, the carb has been rejetted, the oil injection removed, different fenders, wider axle in the rear. Needless to say it runs pretty fast except for a little bog down below, but the thing has sat for over a year with only a couple starts here and there with old gas, due to a broken chain.. I'll have the carb cleaned soon.

Well, we decided to fix the chain and get the thing running. We put some clean gas in it, with a touch of Seafoam, and let it idle for a few hours to clean it out. Lately we have been riding it all week with no problems whatsoever. It's been running great! Except until a few days ago. We decided to drain the trans fluid and put in some good oil. The service manual says any plain 10w30 motor oil is fine. So we fill it up, and run it around like 5 minutes until it starts spitting oil out from behind the front sprocket somewhere unknown, at a good rate. It's not coming from the drain plug, I know that. When it's revved up it definitely squirts a bunch. Today, I drained it and put in some Mobil 1 ATF Type F, also an acceptable trans fluid, and I get the exact same thing..

Anyone have any idea what's up with this thing? I imagine it's some blown seal, but I have no idea what it would be. These are not my expertise. Also any suggestions for me to do to to this thing modifications-wise would be great. I know very little about modding these things. Thanks

 

[DirtDiggler]

how much did you put in? it takes less than a quart to fill the transmission , so if you dumped in a whole quart , then you blew the seal in doing so.

 

[sicivicdude]

It could be a broken left side case from the broken chain.

 

[HoLLo]

The first day we put about 3/4 of a quart in it. Yesterday when I drained it and put in the ATF Type F, it was gushing real bad too. Today, I took it out and rode around some circle for a bit, and barely saw any leaking. A little, but nowhere near the amount of the first oil? Maybe it's still trying to work out remnants of the old oil?? :-/

And as far as a broken left case, it never dripped a bit until we drained the oil over the weekend. We rode all last week on a new chain without a drop coming out.

 

[99blaster:)]

mabe it wasnt full of oil when it had the old oil in itand the case is broken but the oil level wasnt high enough for it to leak out. as for the slowing down of it gushing it could be because the oil level is droping due to the leak. this is just my guess and it takes 650ml to fill the case btw

 

[Braaaptor]

Yeah, check the oil level daily as you ride and see if it drops. In the pic of the Blasy, that chain looks awfully tight...run the chain too tight for too long, and it will wreck the countershaft bearings and cause a leak...even if you install a new seal.

I'd check the drive sprocket and shaft for vertical play and see if any is present. If no play is present, you can get away with a new seal and go back to riding. Assuming the leak hasn't already stopped, of course.

 

[HoLLo]

mabe it wasnt full of oil when it had the old oil in itand the case is broken but the oil level wasnt high enough for it to leak out. as for the slowing down of it gushing it could be because the oil level is droping due to the leak. this is just my guess and it takes 650ml to fill the case btw

Well, I added about as much as i thought had already leaked into it today. I'm sure it has enough. I took it for a ride today, and the leak has definitely slowed down a bunch..

Yeah, check the oil level daily as you ride and see if it drops. In the pic of the Blasy, that chain looks awfully tight...run the chain too tight for too long, and it will wreck the countershaft bearings and cause a leak...even if you install a new seal.

I'd check the drive sprocket and shaft for vertical play and see if any is present. If no play is present, you can get away with a new seal and go back to riding. Assuming the leak hasn't already stopped, of course.

The chain isn't extremely tight, as it does have a bit of up and down play in it, should I loosen it up any? I don't have any play in the drive sprocket, and what's the exact description of the seal I would need? Thanks.