Oil leak!

[Chris Launders]

Oh!! how I would love to be tracing an oil leak on a Rapide, if you want to make it interesting try a Black Shadow, shiny black on shiny black, you don't even know you've got one until it leaves a puddle or if it's just a weep gathers thick black oily dust over a large area.
Chris.

 

[SteveW]

A

My Rapide had an oil leak in that area recently. It turned out to be a crack in the valve cap itself. The crack was difficult to see as it was caused by too much force on the cap wrench. All of the flats on the cap had short vertical lines from the use of the wrench over the years and one of those lines had oil weeping from it. I replaced the cap with a spare I had been given, knowing that the problem was solved. It was a bit of a shock to still see oil leaking in the area, but now a reduced amount. It turned out that the replacement cap had a tiny pinhole in it!
Here is something else I learned- if you do have a cracked or pinholed cap, do not attempt to weld it. Instead, use JB weld or some other epoxy.
The caps are not a weldable alloy, at least the cracked one I destroyed while attempting to weld was not.
In doing so I broke the number one rule of motorcycle repair- Do not break the part you are attempting to repair!
Glen

Also, "If it isn't broke, don't fix it."

 

[SteveW]

Oh!! how I would love to be tracing an oil leak on a Rapide, if you want to make it interesting try a Black Shadow, shiny black on shiny black, you don't even know you've got one until it leaves a puddle or if it's just a weep gathers thick black oily dust over a large area.
Chris.

You wanna trade?

 

[ogrilp400]

Yes, Black Shadows are a right pain to trace oil leaks. Some times I think the real reason they were painted black was to disguise the oil leaks.

Phelps

 

[Chris Launders]

I don't think you would really be interested in a trade, my "black shadow" is a 53 comet with a black painted 50 rapide engine, it's been that way a least 40 years. Anyway several people would NEVER forgive me.
Chris.

 

[SteveW]

I found the leak w/ a little help from my friends. After being advised to take a close look at my rear timing side head bolt on the front cylinder for leakage, which was bone dry, I noticed the rear of the head somewhat oily. I packed terry cloth into the cylinder's timing side cooling fins and took the bike for a run. Upon inspection I saw that the towel under the spark plug fin was wet. The leak was coming from the rocker feed to the intake valve. The oil was running down from the intake's rocker oil feed, down the back of the head, then right to the first cooling fin and then ran forward to the exhaust valve's tappet cap and wicked under it to the exhaust nut and dripped off on to the mag cowling. The forward cylinder's intake valve's rocker's oil feed is difficult to see and difficult to access. It's bolt comes up hard against the bottom of the oil tank and it's difficult (to say the least) to extract the banjo fitting to replace the seal. After dismantling all of the oil lines attached to it, I was able to extract the culprit and change out the seal.
Thanks for the input and remember it ain't the fix'en it' s the find'en that's hard. S

 

[SteveW]

Not sure how far you've gone with your "mummifying" - the front exhaust nut is one of the lowest points on the front head, so oil leaking from the inlet feeds etc can find its way down there.
Cunning things, oil leaks - Ninjas of the problem world, hit you where and when you least expect.

Good Luck.

H

Wish I had paid closer attention to this post, since this was the problem.

 

[Albervin]

As you say, the rocker feed oil bolt on the front intake is a a bit of a nuisance to access. I make the bolt a little bit shorter than the others so it can be removed without dismantling the oil lines. By the way, you only had to dismantle part of the oil lines not the lot.

 

[SteveW]

W/ the oil lines attached I could not kick it back enough to clear the bolt, even w/ all of the lines off of it, I found it was still difficult to remove.
Here in NE it's getting wet and cool, so it's perfect Vincent weather.

 

[Howard]

We all get rogue oil leaks from time to time, most are due to operator error - under tightened banjos, using gaskets twice, splitting washers by over tightening..................................... and usually cheap to fix, if somewhat infuriating to find.

H