GL1000 Left Rear Cam Seal? (Solved, If Not Fixed)

[Lucien Harpress]

I snagged a generic seal (with the right dimensions) off the internet and popped it in a couple days ago. A ride around the block didn't turn up anything, but I'm hedging my bets- I've had a pretty bad valve cover leak since I bought the bike, so after all new OEM valve cover rubber, I three-bonded the gaskets to the covers. Hopefully this seals the covers enough to pinpoint any future problems that much earlier.

And if it all goes horribly wrong? I've got two more seals, plus a new cam sitting on the bench. Start from scratch.

(For the record, my last oil leak was DEFINITELY coming from inside the timing housing. The only way this would be from anything other than the cam seal was if oil leaked through the valve cover, through the housing gasket, then out the bottom of the housing itself. Regardless, I need a day of good weather to take a longer ride and re-assess.)

[Lucien Harpress]

After behaving rather nicely for the last few days, I decided to check up on my persistent little problem. Valve cover leaks seemed to be a thing of the past, so score one there. I went ahead and checked the timing cover-

Oil.

So, I once again took everything apart, finding more puddled oil along the way. I got down to the seal, and found that the acceptable amount of threebond on a cam seal is "none". The little bugger had walked itself out of place AGAIN, and only stopped due to hitting (and rubbing on) the rear of the advance mechanism.

In light of this, tomorrow after work we're going full nuclear option. Cam holders off, new cam, new seals front and back. I'm sick of dealing with it; this cam has lost "being in the engine" privileges.

EDIT: In prep for the cam swap I pulled the timing belt cover on that side. Sure enough I had a small oil leak from the cam seal on the front end as well. From around the cam, fairly clearly. So guess it's a good thing I'm going back in.

[Whiskerfish]

[Lucien Harpress]

The problem with constantly working on a bike like this is it's really unfortunate when you have to step away for a couple days. But that's definitely the case here. Otherwise this thing is going to drive me bananas.

Long story short, I got a new cam, two new cam seals, took everything apart, sanded and polished the mating surfaces that butt up to the outside of the seals, bolted everything back together, three-bonded the HECK out of the valve cover seals into the valve covers to stop those leaks, got it all back together, ran it around the block- seemed fine.

Had a quick detour THE NEXT DAY due to a radiator leak (that turned out to be a bad radiator cap), finally got that figured out today, took it for another thrash around the block- sure enough, timing cover is leaking AGAIN. Same amount as before.

I'm at my wits end. Short of pulling the entire head itself and either replacing it or getting a machine shop to re-bore the cam journals, I just can't understand what I'm doing wrong. I realize I'm an idiot, but even a broke clock is right at least twice a day.

....like I said. I think stepping back for a couple days would be helpful.

In the meantime, I may start looking for valve covers. I initially passed on them as a possibility, because not only would oil have to get past the valve cover gasket, it would have to get past the timing housing gasket as well, and the amount of oil that collected in that housing seemed egregious for that to happen- I would think it would flow around and collect on the bottom of the valve cover instead. But on the flip side, that valve cover has ALWAYS leaked since I owned the bike, it still leaks now, and if I'm honest the gasket on the timing housing seems wetter than the cam seal does.

(sigh) I'll give a couple days. Then see what my options are.

[pidjones]

Are you certain that your crankcase is properly venting?

[gltriker]

Yeah. Wits.

[flyin900]

It seems my question was already asked and answered earlier, so this post was irrelevant.

[Lucien Harpress]

Thanks for the help, all. On this particular engine I've never pulled the heads, and the last person that did was Robin, so I trust everything deeper than the cam holders is up to snuff.

It may be an odd take, but I'm shifting gears back to the valve cover for the moment. Here's the reasoning:

1- I've swapped cam seals THIS MANY TIMES with no apparent changes.
2- I KNOW my valve covers leak, sometimes quite badly. And the left one still does. (My right may be okay, too early to tell)

Valve covers and gaskets are cheap. And while it's a stretch to think the cover leaks enough get past both the valve cover gasket (which it does) AND the points housing gasket (which it might), I'm at the point where I can't rule it out.

[robin1731]

Chrome valve covers?

[Lucien Harpress]

Nope, both stock. Oddly enough.

[pidjones]

All that I have ever needed for my valve covers was a bit of Indian Head to tack the gasket in place and make 100% sure the groove and face are clean of any previous sealant. Also, your valve cover bolt seals must work well.

[Lucien Harpress]

So dumb question, but is it possible to over-tighten a new gasket? I realize the cover bolts have a stop on them, and I never crank them hard past that, but I do have them butted up to that stop.

It does look like I've got quite a bit of seepage on the half-circle part of the gasket right next to the points cover. Bolt grommets are new as well. Well, OEM, but seem to seal tighter than new aftermarket.

[pidjones]

The only place that I've seen an issue is the corners of the half-moon. Otherwise, it should seal well. Honestly, I've been able to reuse them most of the time. I seem to remember a ribbed area over the half-moon part. But I've not had one apart for a year or so.

[flyin900]

Are you using OEM valve cover gaskets? I have found aftermarket ones on the big DOHC litre motors are junk and always leak. Different motor and valve cover, yet aftermarket ones could be part of your issue.
New valve cover bolt seals are a must too, as they get compressed with age and heat and don’t clamp as well.
Can you place your valve covers on a sheet of glass to check for flatness at least on the main areas?

[Sidecar Bob]

I find that the only way to get the valve cover to seal at all reasonably is to glue the gaskets into the covers with 3 Bond and then apply a thin coat to the side of the seal that mates with the head, and even then the bottom of the cover eventually becomes greasy.