Zr 550 stator cover oil leak

[hugojose]

Good for you. In my opinion, you have little to lose, face with the possibility of splitting the engine. If it does not work it may leak again, but you were already there with the old seal, and hopefully, it will hold.

Interestingly, the 750 crank seal does not seem to have the ridge on the diagrams, like on the 550.


How difficult was extracting the old one????

[Sykesweld]

The old one pulled out easily but as the picture shows it was forced in and covered in permatex. I can’t track down the former owner but at some point the seal was replaced and the ridge was torn off . Hence the permatex. I’ll do a follow up post after I get some miles down.

[David Richard]

hi sykesweld i think you have done what many would try first before a engine strip ,i did this on a rd 250 engine many years ago the oe seal had the normal lip on it but i got one without it and it worked fine i suspect yours had the lip cut off ,have you had the engine running and in use ,but to hugojose do you mean the engine cassing have no place to put a c clip in the cassing or no lip on the seal on the 750 s ,thanks david

[Freddy]

Well done. I must admit when you first suggested you approach I thought you would even struggle to get the old seal out. So good effort.

[hugojose]

.......but to hugojose do you mean the engine cassing have no place to put a c clip in the cassing or no lip on the seal on the 750 s ,thanks david

David, I suppose your question relates to the statement I made about the 750 not having the ridge on the crank seal.

No, I do not know for sure as I have never splitted the cases. But comparing the crank microfiches of the 550 and the 750,....... the 550 shows the ridge on the seals, but the 750 does not, suggesting they have smooth lips. However, they both show the groove on the crankcase.

Remember these are only diagrams, not the real thing, but if true, it may suggest the 750 would be easier to drive the stock seal in w/out spplitting, as it would be held by pressure. After all that is the way most automobile engines are. One does not split auto engine to change main seals. This may be significant as our bikes are getting really old.

......given the seals are so inexpensive, I may order the ones for the 750 just to see what they look like.

[Sykesweld]

The seal that came on the bike ( leaking with permatex ) had the lip but half of the lip was sheared off most likely from when the former owner tried to put it in without splitting the cases. In the 550s case there is a machined groove 8mm outward from the seal seat which just happens to accept a snap ring perfectly. Yes a took the bike out a number of times and it is dry. My real worry as Someone stayed was the possibility of the crank shifting outward . This second machined slot just may be my saving grace . The bike runs awesome.

[hugojose]

OK, no need to order seals. The microfiche may not show it, but the 750 seals also seem to have the ridge. Searching by part numbers on Ebay, there are some available with pictures and seem to be same type as 550, thus forget what I said. They simply looked smooth-lip on the diagrams.

[David Richard]

hi sykesweld thats good news keep us posted i hope the crank stays put ,what year is your bike ,my thoughts are you hear people talking about engines have been mothballed it may be something we are going to go through ,thanks david

[David Richard]

hugojose thanks for clearing up the seal question ,yes thats good to know the cut out is there to take a snap ring , maybe freddy might come in here or any one who has split the casses ,the lip on the seal would surely just hold it from moving and help seal the joint ,sykesweld said about the crank moving i would think it would rely more than a bit of plastic ,thanks david

[Sykesweld]

I’ll keep everyone posted on my bike . It’s a 1990 . If you look at a picture of the cases you’ll see the machined groove I’m talking about.