Burning oil smell, no visible leak

[91st11rookie]

Hi, I just picked up a 91 St11, I'm presently just commuting to and from work with it and noticed a faint burning oil smell. I took the lower fairing and side covers off and checked for leaks but found none. It has 20k miles on it. I'm going to do a coolant flush and oil change on it, but want the "leak" found and fixed prior.
It sou ds good to me, no smoke from exhaust, no signs of smoke coming from engine...
Any ideas what I can check prior to taking for service?

also- this is my first sport touring, I'm from a long line of cruisers and cafes. This is so much better than them! I love the ride, and the weight is barely noticeable... except on hills lol.

 

[jwumpus]

I had a similar problem on my 91. Faint smell of oil, particularly just after starting and running for a bit. Drove myself crazy trying to find the source. In my case, it turned out to be that I didn't replace the crush washer around the drain plug after changing the oil. Mostly because I didn't realize it had one. So there was just the tiniest leak, enough to create a faint burning oil smell.

 

[Al st1100]

check closely the exhaust. Since it is faint it you may see marks on the top of the exhaust but not enough to drip down. 91's had oil cooled alternators that leaked at the rear of the engine.

 

[Ron]

Nice looking bike! I've always liked the silver ones.

I'll second the alternator seal leaking. I don;t think there are any of the Honda seals left.

 

[91st11rookie]

I had a similar problem on my 91. Faint smell of oil, particularly just after starting and running for a bit. Drove myself crazy trying to find the source. In my case, it turned out to be that I didn't replace the crush washer around the drain plug after changing the oil. Mostly because I didn't realize it had one. So there was just the tiniest leak, enough to create a faint burning oil smell.

Thanks for reply- it is bone dry at the plug, tiniest bit of grime on rear side of pan.

check closely the exhaust. Since it is faint it you may see marks on the top of the exhaust but not enough to drip down. 91's had oil cooled alternators that leaked at the rear of the engine.

Thanks Al. When I had the fairings off I couldn'tsee any noticeable markings on top of exhaust, but it was already 9pm and i was on the ground without a bike lift. There was minimal grime build up on the rear of the pan just behind oil filter area. And I do mean minimal. And there was nothing evident of fresh oil. I wiped it off and will be checking it this weekend.
If it is the alt is the only solution upgrading to the later 40v? And if so, where can they be found?
I suppose it's just fine to ride it the way it is presently until the "no leak" becomes a big leak. Or would I be wrong in that assumption?

Nice looking bike! I've always liked the silver ones.

I'll second the alternator seal leaking. I don;t think there are any of the Honda seals left.

Thanks, Ron. Can they be reproduced? Is it a gasket or an o-ring? I've made plenty of gaskets for antique trucks I rebuilt, or it is too much of a hassle?

 

[91st11rookie]

Well, here is the issue, I didn't see this when I pulled the fairings off previously... also is the breather tube supposed to be like that? Or is that another issue??

 

[Sunday Rider]

Hi, nice looking bike!

Have a look at post #61 in this thread, if this might be your problem?

Another Uncle Phil Interesting Running Mystery | ST1100 Related

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