On the road again at 40.............the bike that is

[robinc]

Thanks Bob. Like you, when I see what might be an interesting backdrop, I pull over and snap a couple photos..

As you once said, I can't believe I did without that tail bag. Super handy. Can fit my leather jacket for the return trip home with room to spare. Also has 2 zippered side pockets and a bottom zipper to increase the bag size vertically to hold a full face helmet. Comes with a rain cover as well.
Very happy with it!

 

[Jim]

With airflow blastin' past the engine, oil can wick it's way up into the points housing... but yeah, judging from the puddle in the first pic, it does look like the cam seal. Only one way I know to fix that.....
Was the end of the cam pitted any?

 

[robinc]

Well Jim, I think these pics would indicate that it's the seal and not the gasket. Looks like a bloody oil refinery in here.

As you would expect the bottom of the points cover was wet as well..

I'm really quite surprised at this failure. New OEM seal set with Threebond, new o-ring and new gasket. Using a vice, socket and plywood blocks, I pushed the old one out and set the new seal flush with the inboard side of the housing. As I have now read maybe I should have set it a bit proud and inboard somewhat. But I think that applies more so to the Mikes seals and not the OEM.

Just saw your latest post as I was typing this Jim.
Here's the best pic I have (enlarged a bit) of the end of the cam.

Doesn't look too bad. Unfortunately I hadn't read 5twins trick to clean it up a bit with a Scotchbrite pad until it was all back together.

These seals are pretty easy to change, so that's a pain but not a huge job, and as I mentioned I already have extras.
I just can't imagine how I'm having to do this with only 1341 kms / 833 miles since it was installed.

 

[Jim]

I just can't imagine how I'm having to do this with only 1341 kms / 833 miles since it was installed.

Hard to say Robin. Maybe there's a burr on the cam (scotchbrite it).... could have been a defective seal (it happens)..... could be you messed it up when you installed it. That even happens to us old timers on occasion.... Like you said, you have a spare and it ain't that big a pain...

 

[robinc]

Thanks Jim, I guess those are all possibilities. And here I thought how easy these cam seals were!
Can't remember even skimming a whisker of material off when I installed it. Ah well.

Doing things on this bike reminds me of my grade 12 experience. I liked it so much I did it twice!

 

[MaxPete]

An old hydraulics instructor of mine once said:

“Pete, there’s only two kinds of leaks - those that are happenin’ now, and those that are gonna happen someday..”

He was right - dammit.

 

[5twins]

Are you sure you fully seated the bearings on the end of the cam and then centered it in the head? The amount of bearing inset in your pic looks a little light. That can hold the points housing out too far, not allowing it to seal properly against the head and on the cam.

 

[robinc]

Thanks 5twins.

Well, I thought I was pretty careful with that, but perhaps not. That does make the most sense as to why a new seal would be leaking this much.

Maybe I will be able to tell when the housing is removed?
Should I back off the studs and see if I can seat the bearing further?

Additionally, should I pull the advance housing to check it and measure the depth of seating of both to compare?

 

[5twins]

Well yes, you may have to remove both housings and measure the bearing inset on both sides to see if they're the same. But even if they are, that doesn't mean the bearings got seated onto the ends of the cam all the way. I never did measure and record the bearing inset during a rebuild, I should have.

This brings up a possibility for your metal flakes and maybe even the random ticking. If the cam bearings aren't pushed all the way in on the cam as far as they can go, the cam could float left and right during operation. Maybe that's inducing a little occasional cam chain rub in the tunnel.

 

[robinc]

Ok, thanks. I will pull both housings and measure.

Here are some assembly pics but I don't have one of the final before putting the rocker cover on. There is definitely a gap between the bearing and outside lobe. In this picture the advance side bearing is defintely seated in further. I think I set these further, but maybe not, and no photo to verify unfortunately.

I think I have read in a post of yours that it is possible to back off the four outside studs and tap the bearings in a little further. Am I right on that and is that advisable or is there really only one hard way to do this?

Thanks again 5twins.

 

[5twins]

I don't think that was my post, but I've heard too that you could do that. I think I might loosen all 8 big acorn nuts though, and the cam chain adjuster too. You'd probably need to loosen the 8mm top cover bolts too, at least the center ones around the cam. For tapping in on the bearings, I think you'd want something pretty wide, wide enough so you're tapping on both the inner and outer bearing races together. The cam bearings are a pretty precise fit on the cam and into the engine cases where they sit. Tapping on just one race (inner or outer) may not move the other with it, might just bind the bearing up.

 

[gggGary]

Would prolly have to machine a "bearing pusher" to do it right....
Madness has a light "cam drool" on one side.
A "trade goods bike" currently in the shed has an oily points housing. Actually that was the wake up. Un-stuck a stuck valve, sprayed housing with carb cleaner and blew it out a few times, cleaned, sanded, cleaned, the points and vroom vroom, LOL

 

[robinc]

Ok thank you again for all the info 5twins. I guess this is worth a careful go at it. Sure beats the alternative.

For tapping in on the bearings, I think you'd want something pretty wide, wide enough so you're tapping on both the inner and outer bearing races together.

I have some large 3/4" drive sockets but 3/4"s of an inch likely still won't be large enough to go over the cam ends. I guess I could use a large washer seated against both races and then just use a large socket against that.
I'll measure cam location at each end so that I can see when it has moved outwards. That should tell me the bearing is fully seated then I'll get it centered.

 

[robinc]

Thanks Gary.

Would prolly have to machine a "bearing pusher" to do it right....

Not having any machine shop equipment to do that, I was trying to think of a MacGyver solution such as a large thick washer.

If I need to get a machinist to rig something up for me, I might as well spend a day, pull it, pop the rocker cover and check everything that way.

If you guys think this is the best way to proceed rather than trying to monkey around, I'll do it.

 

[5twins]

Yes, just the right size washer should do the trick. You may have to mod one for the job. Another "special tool" for the collection, lol.

Something else you could check is the depth of your bearing inset compared to the depth that the step on the points housing sticks in. Measure the step with a gasket present. I wouldn't be pulling the whole topend apart yet until I investigated some of these other possible "quick fixes". But also keep in mind, all this stuff may be fine and maybe the seal just did crap out.

Something else you could try is just pulling the housing and cleaning the end of the cam up with the Scotchbrite pad. Sometimes that alone will cure minor leaks. But then again, your leak may not be that minor, lol.

 

[robinc]

All good points 5twins.

Something else you could check is the depth of your bearing inset compared to the depth that the step on the points housing sticks in.

I thought of doing this to see if the bearing was in fact too far outboard. This may well quickly confirm it.

I have a gut feeling that the problem is due to the bearing seating with the 'not minor' leak that I think it is....lol.

 

[Jim]

.....to see if the bearing was in fact too far outboard.

If it was, your point and/or advance housing would leak past the gaskets/o-rings. You'll know as soon as you pull the housings and find out how much "squish" you had on 'em.

 

[robinc]

Yes, good point Jim. Well I'll get at it and see what we see. Thanks.

 

[Jim]

OK Robin..... I just pulled the rocker box from my XS1 motor and screwed the point and advance housings back on....

There were no gaskets, only o-rings on the housings. On the 4 arrows... housing to bearing and bearing to cam...... a .0015" feeler would NOT fit at any point. In other words.... with no gaskets, there's no room for misalignment in there.
So.... provided your housings seated (I bet they did), the only back and forth you'll get at the cam and bearing would be from the thickness of the gaskets.

 

[Jim]

I never did measure and record the bearing inset during a rebuild, I should have.

I just did. It's right at 5mm.