Oil Leak, GS 850

[Anonymous]

Have a '79 GS850G w/34,000 mi. Have developed an oil leak on the right side. Oil is dripping out of the right side timing cover. What's involved to fix this?
Recently switched to Amsoil synthetic motorcycle oil. Could that have contributed, i.e. incompatibility of old seals with synthetic oil?

[Scud]

Its been rumored that synthetic oil can cause leakage, switch back to dino oil first and see if that fixes the problem.

Scud

[SqDancerLynn1]

Their is a seal behind the timing advance unit Easy to replace uncher it with a nail/drill and insert a screw, grab hold with visegrips and pull it out.
Match the seal dia to a length of pipe / PVC pipe Put some grease on the seal lip & some sealer on the outside & drive it in

[bwringer]

Yup, that's the crank seal. Should be a breeze.

You can order it up from the fiche at http://www.crotchrocket.com , or if you're feeling sporty, you could pull the old one out and take it to CarQuest. They should be able to measure it and match it up to a new one. I haven't tried this yet, though.

If you still have points on that beast, I believe you'll have to take the points plate out to reach the seal. If that's the case, make some match marks so you can get it back in exactly the right position.

[Anonymous]

I have to agree with Scud. Synthetics in the late 70's and early 80's to mid 80's were marginal at best and the seals used during that era were not made to hold up to Synthetic oils. I know a couple people who have spent quite a bit of money trying to figure out what happened to their motorcycle after switching to synthetic only to find out the synthetic oil deterioted a $2 seal.

[focus frenzy]

I have to agree with Scud. Synthetics in the late 70's and early 80's to mid 80's were marginal at best and the seals used during that era were not made to hold up to Synthetic oils. I know a couple people who have spent quite a bit of money trying to figure out what happened to their motorcycle after switching to synthetic only to find out the synthetic oil deterioted a $2 seal.

synthetic oil does not deteriorate seals, it makes the seal return to its original shape, regular oil makes the seal swell slightly and it wears down to the proper size, you change to synthetic and the seal returns to normal size and you get a leak.
the amount of the swelling varies with the differant formulations of oil, but often when a leak starts, changing back will not stop it in most cases.

you can run a new engine on synthetic and never have a problem, but change to regular dyno and run on it for a couple years and then decide to change back to synthetic you risk developing a leak.

[bwringer]

I just tried to remove the crank seal on the scrap GS850 bottom end sitting in my garage.

Guess what? It appears to be held in by a plate -- from what I can tell, it's not like a standard crank seal that just presses into place.

As always, the manuals are quite vague about how this area is assembled and the microfiche is stunning in its lack of detail or accuracy.

So don't start trying to yank your seal out until someone weighs in who has actually done this on a GS850G. If it really is behind a plate (an insanely stupid arrangement, but who knows), then replacing the crank seal would require removing the engine and splitting the cases.

I'll muck with it a bit more tomorrow morning and report back.

Back to the synthetic/dino religious wars...

[Anonymous]

I stand corrected.