Cam Seal Question

[3Deuces]

Hey guys,

I was wondering if the cam seals can be replaced without removing the cam?
Mine are leaking and I've got some new ones on order.
Thanks

 

[DogBunny]

They are very easy to replace. You only need to remove the housings, it is very intuitive.
Use an impact screwdriver to remove the 3 countersunk Phillips head screws that hold each housing on.

 

[5twins]

Yes, you can. The seals are mounted in the little points and advance unit housings, not the head itself. Remove the little housings (3 Phillips screws) and you can do the seal replacement. You will need new gaskets for the housings. There is an o-ring on them too but as long as you don't damage it, you can probably re-use that. I mention this because I don't think Mike's sells just the o-ring separate, only in full gasket or o-ring kits.

You'll probably find the ends of the cam that stick out past the seals all dirty and rusty. Many times, this is what starts the seals leaking in the 1st place. That dirt and rust works it way into the seals, causing them to leak and sometimes ruining them. While the housings are off, buff the ends of the cam clean and shiny with a Scotchbrite pad.

 

[3Deuces]

Awesome as always!
Thanks guys.

 

[blackbetty]

5Twins, I've pulled my left side advance housing off 2 times in an effort to prevent leaks on my recently rebuilt engine, but no matter what, oil always seems to find it's way out.....it's probably exacerbated by the kickstand lean...

Anyway, the cam is centered and the cam bearings are butted all the way on the cam, so I know that everything is good there. I was reading that the athena housing gaskets are too thick and push the housing away from the cam end just enough to cause leaks....

Have you heard of this? Is the genuine Yamaha housing gasket thinner?

 

[5twins]

I haven't heard that about the gaskets. They're working fine so far on mine and one of my buddy's - but his other 650 has the same leak as you on the left side. What I have heard is different is the new seal from Mike's, supposedly a triple lip style. If you don't seat it in far enough, all 3 of those lips won't be on the sealing surface of the cam. Is your seal inset as much as possible?

 

[avenue]

this might be a bit silly, but how are the seals seated in the housings? I thought they were simply pressed into place, from the looks of 'em. I can't, for the life of me, remove the old ones and it's really hurting the ego

Thanks,
avenue.

 

[5twins]

They are simply pressed in and that's how I get them in and out. Find a socket that just fits the seal but will slide through the seal bore. Place the socket against the back of the seal (engine side) and a scrap of plywood on the front of the housing. Place this little "assembly" in a vice and slowly tighten it down. The socket will press the seal into (and out of) the housing. For install, use another scrap of plywood on the back instead of the socket. This will press the new seal in from the back but only until it's flush with the back, which is where you want it so it seals properly on the cam.

 

[avenue]

perfect. Thank you.

avenue.