Hey guys,

I'm getting sick of taking the primary off, maybe someone here can help me before I do it again.

Bike info: 1990 Heritage 5speed, 45K

When I bought the bike last spring, no leaks. ABout 100 miles after I bought it, the shift spring in the trans broke. I got into the trans and replaced the spring. After the though the bike started leaking trans fluid. Last year, I got into it and replaced the main seal ( the big one ). That didn't stop it, in fact it seemed worse. I know I should have changed them all out then, but I'm a dope. This past winter I opened her up again and replaced the main seal, shifter seal, the seal between the pulley spacer and the bearing (quad seal?), and the seal between the I.D. and O.D. of the output shaft ( 5th gear seal?). And after I put it together its leaking worse!

Here's what I know. Its a trans leak. I need to fill the trans every couple hundred miles, the primary fluid stays the same. The leak drips off the back of the primary and the left shock. And its really bad now, not a couple drips. Its not coming out the vent tube.

Any ideas? After changing all those seals it hasn't gotten any better. Could it be coming out the screw that adjusts the shifter pawl?

 

Theres an o-ring behind the shifter paw screw, did you replace the quad seal between the spacer/inner race and the 5th gear???? Is that piece in dood shape or is it worn??? Do you have a lock ring/screw on the pulley nut??? Is the vent open??? What about the "wedding band" seal??? Sometimes you need to put a little sealent on the outer diametr on the main seal.
John

 

The shifter paw screw is wet, I didnt replace any o ring there, but I dont think it would create a puddle. I replaced the quad seal, but not the spacer. Lock ring is on the pulley nut and everything is torqed to spec.

How do I check if its venting properly?

What is a wedding band seal? The one between the output shaft and the gear?

 

I went through the same problem changing out all the seals. It just takes patience, I had swapped out my tranny for a newer one and the guy I got it from couldn't get it to stop leaking then I tackled it. I went right to dealer and got the seals for the newer tranny as well as all the seals for the old welded up tranny and turned out the 1989 tranny and the newer tranny had different quad seals diameters ( the one that goes in the gear end) put the proper one in and no more leaks. It also helped when I started running the red ATF in primary just to verify the oil leaking was from the gearbox. Also make sure you don't have oil blowing back out the gearbox breather hose.

 

take the tranny filler plug out and blow/put air through the vent hose or filler hole. Check the tranny fluid with the bike straight up, not on the side stand.
John

 

Now that John has mention having the bike straight up had me think to say make sure you don't have too much oil, check it wth bike straight up , oil warmed up and filler dip stick just sitting on top of first thread.

 

i chased a leak like that for a whole summer once. it turned out to be the splines on the main gear were worn. if there is the slightest bit of wear the drive pulley will can never get tight. it will wobble on the main gear and that will cause it to leak. i changed the main gear, the pulley, spacer and the seals. problem solved. if the splines on the pulley are worn it will cause it to leak too.

 

Good info!

I also had a leak after putting a Baker in and found the mainshaft spacer where the seal rides on is tapered and didn't have the seal riding on the thickest part of the spacer. Also noticed that the replacement HD seal I put in is superior over the Cometic when viewing side by side, the HD is double lipped and quality looking.

 

Ok guys, I haven't had the chance to get into the garage but these are all good ideas. I'm fairly confident it isn't the seals alone since I've replaced them twice. But the spacer is old and I don't know if the splines on the main gear are worn, but I'll have a look.

Here's my new theory, when I first got the bike the ******* spring broke and I had to go into the trans, that's when the leaks started. Now, when I look at the transmission housing, it is covered in oil all on the side where it meets the primary. But it also is covered on the side between the trans and the motor. The oil coverage is also high on the trans, all the way up to the cover, but not higher. which makes me think its the top transmission cover. I remember it was hard to get to those screws cause I didn't take the oil bag out. Could I be leaking that much from the top cover. Keep in mind the oil stops leaking about 1 hour after I shut the bike off.

 

Can't Definately be leaking lots from the cover gasket , also make sure vent hose is on tight.get a can of brake cleaner and spray the tranny down so oil is gone completely , it will be dry when your done , take it for a ride and check it closely and you will find where it's leaking. Just don't go to far, ride a bit and checkit ride a bit and check it.