08-03-14, 01:51 PM
I had this problem last summer and it was the crankshaft oil seal behind the rotor that was leaking. If your's is too it's not the end of the World you can do it yourself but it is scary stuff!
Basically there's two seals that you can get to replace the leaking one. The original seal that's in the engine now has a lip on the inside of it which means that it has to be pressed out from the inside of the engine so you have to take the engine apart to do it. The second type of seal has no lip which means that you can press it in from the outside and keep the engine together. The new seal was obviously made with servicing in mind.
Here's a post from the mighty Unfazed about it
The biggest problem is getting the rotor off. They're on really, really, really, really tight. You'll need a holder to hold the rotor and stop the engine turning when you're undoing the bolt that holds the rotor on. You'll also need a heavy duty puller to pull the rotor off the crankshaft. This is the scary part as it feels like you're going to break the crankshaft when you're doing it. I got the seal out slightly differently to Unfazed. I drilled 2mm holes in it and then screwed screws into it and pulled it out with a vice grips on the end of the screws.
Basically there's two seals that you can get to replace the leaking one. The original seal that's in the engine now has a lip on the inside of it which means that it has to be pressed out from the inside of the engine so you have to take the engine apart to do it. The second type of seal has no lip which means that you can press it in from the outside and keep the engine together. The new seal was obviously made with servicing in mind.
Here's a post from the mighty Unfazed about it
(12-05-13, 12:19 AM)unfazed link Wrote: No need to strip the motor, Yamaha supply a special replacement seal without a lip on the end.
I changed one on my sons fazer 400 about 3 years ago. :thumbup
Taking off the rotor was my biggest problem I had to heat and it came off eventually with a such a noise that I thought I had broken the crank.
The special seal part number is 93101-29166 and it is about £25, which is over twice the price of the standard seal.
You will need a special sealer, I used RTV 1080 Silicone Rubber Adhesive Sealant.
Carefully drill a small hole in the outer section of the seal sbout 5 mm deep and prise it out with a small screwdriver working bottom to top. It will collapse with supprising ease. Take GREAT care not to scratch the surface of the crank. When the seal is out clean the area with something like thinners, which evaporates without leaving any residue, let it dry well and apply engine oil to the seal lip and the sealant sparingly to the out part of the seal and push it home.
The biggest problem is getting the rotor off. They're on really, really, really, really tight. You'll need a holder to hold the rotor and stop the engine turning when you're undoing the bolt that holds the rotor on. You'll also need a heavy duty puller to pull the rotor off the crankshaft. This is the scary part as it feels like you're going to break the crankshaft when you're doing it. I got the seal out slightly differently to Unfazed. I drilled 2mm holes in it and then screwed screws into it and pulled it out with a vice grips on the end of the screws.