Drive Shaft Leakage

Hey Everybody, looking for some technical help. Took my 750 Seca out about a week ago for the first time, there has been oil dripping out from the drive shaft since. It started slow and has built to a consistent flow when the bike is tilted towards the drive shaft side. It no longer leaks now that the bike is on its stand. Pics attached; the leak seems to be coming from the ribbed rubber boot at the start of the drive shaft. Any thoughts?

Is the boot supposed to have oil in it? This is my first time messing with a shaft as my last bike was and Xj550 so it was chain driven. One theory given to me was the bike had too much oil, but that doesn't make too much sense to me, but maybe you all will tell me otherwise? Going to start taking it apart in the AM to see what i see. Thanks for all the help.

 

Additional info, Leak went nuts when i started the bike to bring it into the garade.

 

Welcome to the forum. Behind the rubber boot is the universal joint. The engine side of the joint has an oil seal behind the four bolts that holds it to the crankcase. Do you have a haynes manual for the bike?

 

Seal behind this flange. Oh I forgot there is a big O ring in there it is probably that. Better replacing both when you strip it. Leak went nuts because the engine was running. With the bike on the side stand engine oil flows to the drive shaft side. Rubber boot does not contain oil it is there to protect the universal joint. Make sure first the oil is not leaking from the gear change shaft cover.

 

Two options as Franz noted the final drive has a large O ring to replace you can pull the engine from the bike or remove the swing arm ( this will move the drive shaft out of the way this will give you clearance to remove the drive flange NOTE: THERE are shims behind there that have to be reinstalled. There are four bolts that have to be removed and two 12mm case bolts above that have to be loosened and two 10 mm bolts as well next to them. The left hand side cover so shift linkage has to be removed. This sounds complicated but is actually pretty straight forward . The gasket and O ring can be bought from xj4ever while your at it not a bad idea to replace the shift shaft seal . I split two of my engine cases last summer replacing the starter clutch so this is from part of doing this . Removing the engine , pull exhaust put bike on center stand, disconnect drive shaft ( four bolts behind the rubber boot) pull carbs , remove the foot peg bracket bolts and pull front bracket , drain engine oil , remove the oil filter housing. I use a floor jack and a milk crate , Jack up engine slightly move over frame tube , move over onto the milk crate . A helper is nice but I did this by myself t. Removing takes about a hour . Attached is picture of the shaft back side you can see the shaft flange.

 

First of all, thanks for the welcome and help. Ok, I peeled back the boot and got a good look at the Universal joint you guys are talking about, pretty sure that's the issue. Is there any special technique to removing the drive shaft or is it pretty straightforward? I think I'll go the swing arm route; I've done that before on my chain bike. Seems simpler than taking out the engine. I'll update soon.

 

You have to disconnect the drive shaft from the engine four 10mm bolts , disconnect the shocks, disconnect the rear brake rod , pry off the caps from the pivot and the bolts on the left side had a tab washer that has to to be moved up and then you can back them out and then arm can be removed . I will tell you make sure you keep the boot in place when you reassemble you can't install it afterwards . Please note you can remove the differential four 12mm bolts , but you may get some gear oil leakage, this will lighten up swing arm . Good luck

 

Photo of driveshaft removed from engine on this thread.

https://www.xjbikes.com/forums/threads/replacing-engine-seals.129343/#post-650581

 

Ok, I've made some progress in getting to the problem. The Back tire is off, and the drive shaft itself has been pulled out. I left it in where it enters on the wheel side. I got two questions, the first one is, can i remove the metal piece the drive shaft tunnels through on its way towards the engine? It seems to be part of the frame but getting it out of the way would make things a lot easier.

The second has to do with what's connected on the engine side. Underneath the boot, there are four bolts connecting it to the engine side, it looks like this seal is what's causing the leak. The inner ones are a bit tough to reach. If I get these bolts undone, will the spinny contraption just be able to pop out? What is this thing called? Sorry for all the novice questions, help is greatly appreciated.

 

Oh wow just realized your in Chicago I live in northern Indiana lol after you remove the bolts on the output shaft flange you will need to lossen the two 12mm bolts on the case and you should be able to remove it . Be aware of the shims behind the flange these have to be reinstalled a bit of axle grease helps when reinstalling.

 

Hey Jetfixer, I used to be in Chicago but a few years ago my wife and I moved to Raleigh NC. I think I made the account a while ago when i have the 550 maxim. How is Indiana treating you?

On the bike update, things are not looking good, I'm pretty sure I fF'ed up. I'll try to step by step. I wanted to watch the leak to make sure I knew where it was coming from. So, I peeled back the boot, started the bike, I didn't see any leak. However, I know the engine has very little oil because it was all on my garage floor about 5 days ago. So, I add about 1.5 qts, start the bike again and look for the leak. For about 30 seconds, the bike runs like normal. The oil starts pouring out the back, but it's not coming from behind the drive shaft boot like i thought. It's actually coating the bottom of the box the is right above the drift shaft, behind what I believe is the alternator. It's the exposed plastic box in the picture attached. Then the bike made some scary sounds and shut off. I tried to start it again, nothing good. Anyone have ideas about hot screwed I am? What is the inside the box basically between the battery and the alternator?

 

Don't assume the engine is ruined. From what you indicate it is the air filter box. There is a black hose coming off the gear change cover to the right of the starter motor that is connected to the air filter box. Remove it and remove the cover on the air filter box to see if the filter is covered in oil. Perhaps your engine has been overfilled earlier and excess oil has been forced out of the crankcase breather hose into the air filter box. I think that is the reason for your oil leak.

Is there excess smoke coming from the exhaust system? If you are getting oil in the airbox and it is getting sucked through the carburettors it will burn the oil.

On the clutch cover where your footbrake lever is there is a window. That is where you check the engine oil level. Do you have a Haynes manual that will help you with maintaining your machine.

How long have you had the bike? Was it off the road for a long time?

 

^^^+1 agree with Franz

 

Ok, very happy to hear these ideas, and you are making a whole heck of sense. We did notice some smoke coming out of the exhaust after the bike stopped running. I don't have a Haynes manual, but obviosly need one, where is the best place to get one? I've had the bike for about 3 years, it had been off the road for the winter only. It was running great into November. I'll open up the filter box tomorrow.

 

Also, if there is oil just blasting out of the breather hose and into the airbox, then we've got to wonder why. If it's not overfilled, maybe some of the filter/baffle for the breather is missing.

 

Yup I think that is under the screws on the inside of the gear change cover.

 

Check your spark plugs too they could be oil fouled.

 

Check the oil level as suggested above

That statement is very common when fuel has entered the crankcase and effectively overfilled the system

Take a whiff of the oil, does it smell like gas?

 

So, the air filter is supposed to be brown right????? Definitely some oil coming into the airbox, pics of the filter attached. The internet has given me varied answers on the amount of oil to add when its empty, about 2.5 qts? I'm going to give it an oil change, change the filters, and see if that solves the problem first. Hopefully I don't end up needing to look for anything else. So, I got the oil filter off, but I can't move the oil drain nut below it because someone decided it was a good idea to wedge it deep in there. Is there any trick or tool needed, my ratchet head won't even fit in the space required to get on the nut. Thanks for going on this journey with me, hopefully I can put it all back together.

 

Will also peek at the spark plugs, great thought.

 

Can you fit a deep socket on the drain plug? Make sure you clean the inside of the airbox you don't want oil on your new filter. As Rooster started it is worth checking for gas in the oil. If the petcock is faulty or the float valves are not seating property fuel can get into the crankcase. If you have the original Yamaha petcock on the bike fuel should only flow when the engine is not running on the prime position. The vacuum from the engine makes fuel flow only when the tap is on main or reserve. Chances are you don't have fuel in the oil as the bike was running well last November but it is still worth checking this.

 

Can you post picture of the oily air filter? You can remove the breather hose from the stub on the engine cover. Then fit a length of similar hose on the stub and put the other end in a bucket or oil can. If oil gets out of the engine when you run it you won't ruin your new oil filter. If it does not your bike is fixed .

 

Ok, So I have good news and bad news. The good news is, I definitely had too much oil, and it seems like they might be the only issue. I've checked the petcock, its seems to be functioning correctly. After emptying the oil I probably pulled over 4 quarts, not including the extra quart that leaked all over my garage. I have a new oil and air filter en-route so I have to wait to confirm. But the bike starts and seems healthy. I re-attached the picture of the air filter.

The bad news is, after re-installing the back wheel I never needed to take off, something is not quite right. I went to test the tire (on the stand) after getting in re-installed. Turned the bike on, shifted into first and heard a clunk. I immediately put it back in the neutral and stopped what I was doing. The tire doesn't really spin (a problem right...), and the issues seems to be due to the connection to the transmission. Is there something i could have missed when re-installing? Does it just need to move a little bit to pop into place? Thanks for the help.

 

Did you remove the swinging arm or just remove the driveshaft from it? If you removed the swinging arm you need to centralise it. You don't want that out of alignment.

 

I removed the driveshaft but not the swinging arm. I'm going to take it off and put it back on again today, maybe its not aligned right?

 

You can take the spark plugs out and run the machine through the gears. Put the bike on the centre stand. Turn the back wheel as you are moving the gear lever to see if you can select them all. The clunk you heard is normal when you put the bike in gear. Try it without the engine running it might save you dismantling the driveshaft again. I doubt you could assemble it misaligned you would have had resistance on the nuts at the hub before the faces met.

 

Ok, waiting on my oil filter, I feel i probably shouldn't do that too much with first putting the oil in. Its been arriving today for like 3 days.... Just out of curiosity, why take out the spark plugs?

 

Because it will be easier to turn the engine over as compression won't happen. Your valves will be closed on the compression stroke but the pressure cannot build up.

 

Ok, so basically i think I'm just having trouble getting the splines on the end of the drive shaft back into U Joint (this is what the joint under the boot is called correct?). Any tips on the best way to do this? The U joint keep moving on me while I'm trying to get the splines properly lined up.

 

Yes the joint under the boot is called the U Joint. Do you have enough space to wrap a zip tie loosley around the U joint to hold it up so you can fit the shaft into it. Mabe someone will chime in with a better solution if they have fitted it with the swing arm on the bike. Good luck.

 

On my XJ that u joint has enough resistance to hold itself up. I use a torch and stick a bar in there around 1/2 inch diameter to get it lined up. Then I carefully insert the shaft and push it in. Once in I then lift the drive casing into place. Hope this helps…