[harley_z]

I have a 1991 XLH 1200. I recently changed to synthetic oil and am now noticing some oil dripping off the swingarm. I'm trying to find where this leak is coming from, with no luck . Any ideas would be greatly appreciated.

Thanks.

[fatboyvtwin]

The easiest way to track down a leak is to thoroughly clean the whole area under and on top of the swing arm. I have always used contact cleaner with the fine red tip to get intense and accurate flow. When the area is cleaned, "spotless" start the bike and let it idle till the motor oil gets hot. Check under the bike for the leak, if there is no leak then take the bike around the block, then park it to see if there is any oil seepage. If that doesn't work try to take it a couple of miles and then stop to check under the bike. Some leaks may take a few hours of the bike off and sitting to surface. As far as you going to synthetic oil, be aware that synth oil is not as heavy as regular motor oil and on that older of a bike may have found an area to leak out of a seal. Ride Safe, David.

[shaymus]

Originally Posted by harley_z

I have a 1991 XLH 1200. I recently changed to synthetic oil and am now noticing some oil dripping off the swingarm. I'm trying to find where this leak is coming from, with no luck . Any ideas would be greatly appreciated.

Thanks.

In my experieces, you can't have any leak's withsynthetic oil.Whether motorcycle or car.

[Tumshie]

I would look at the oil tank breather or one of the tank lines.

[voodoo1]

when you switched to syn it now is "weeping out" when warmed the metal is expanded and more vulnerable to weeping ..... "real" oil builds up/around in the gaskets/seals so to speak and helps plug any small intolerances along with the gasket. the syn will go right on thru now that ya switched to...seen it over and over when people have switched.(as mentioned above) .. the more the metal has heated and cooled causes the tolerances to vary more than the current gasket can handle..no more real oil build-up anymore.... whammo here comes the weeping.(so to speak)

[hotroadking]

A bit more, what happens is the dyno oil can only clean contaminants so much, then it begins to leave deposits, some will form where you have a gasket leak and will plug the leak.

Over time with use the synthetic has better cleaning agents and lasts longer so it cleans out the area the dyno oil left the crud in. So you get a leak.

Now that may not be the reason, syns' don't cause leaks they can find them though.

Check all the connections make sure nothing is loose anywhere, it could be a loose hose or cracked hose somewhere.

Changing back to dyno wont help if you really have a leak.

[hdotis69]

In past experience ive noticed sportster oil tanks leak around one of the welds.