how fast does your oil darken?

Hi all,

1982 550 LTD. Few years back I holed my #2 piston. After alot of screwing around, I FINALLY have it runnining right again. One think I notice though is when I dropped my oil the other day and replaced it, it seemed to get darker rather quickly.

Now, the oil that was in it was about 2 years old, and I have some leftover from the wife's scooter and my shadow, but no filter. The filter only had maybe 15 miles on it, so I just dropped the oil and filter, but put the filter back in. I plan on replacing it very soon, but the bike isn't even licensed yet, so I don't go anywhere with it. I just wanted to get that old oil out of there...

Anyway, now I'm worried that I might have some blow by from the cylinder I blew. It has new rings, valve seats and a hone. It's compression is about 130, whereas the others are 150. I was *hoping* that once I get some miles on it that it would increase a bit as the valves and rings wear in....

How could you tell if I do in fact have blow by? A leakdown test would show that, but wouldn't it show the same thing if the valves weren't perfectly tight too?

Glad you got it back together!
You should have replaced the filter as well. Used motor oil becomes acidic over time and will react to the rubber and metals in your engine, especially aluminum. The filter will hold oil in it and when you fired the engine up, that oil just got recirculated with the new stuff.
A leakdown will tell you whether you have leaky valves or ring blowby by listening to where the air is leaking; intake, exhaust or case.

yeah, I knew it wasn't the best idea, but I just wanted to get that old 2 yr oil out of there and figured that I would be replacing it within a week anyway.

apbling wrote: Now, the oil that was in it was about 2 years old,

You may have sludge buildup in the engine because of that. Buy some gallons of decent oil at Walmart and change the oil frequently (whenever it turns black) and maybe it will take some of the crud out.

Now, alot of people have been talking about the diesel rotella T. Is that what you are referring to? Don't tell anyone, but she's got Honda oil in her now.... (my wife's scooter takes just under 1 qt and the shadow takes 3 and some change, so I just buy two big jugs at the honda shop, so I used the leftover in the 550)

The oil that was in there was actually 10-30 regular motor oil. That's all we had at the time, and figured it was good enough for just getting it started. Maybe it's all in my head, but I SWEAR my clutch feels better now that it has motorcycle oil in it and not regular motor oil. I used to have issues with the plates sticking together, so after it sat a little bit and I started it and put it in gear, it would snub because the clutch was clinging a little bit. Usually once it did this it was fine to go.

apbling wrote:
The oil that was in there was actually 10-30 regular motor oil. That's all we had at the time, and figured it was good enough for just getting it started.///Maybe it's all in my head, but I SWEAR my clutch feels better now that it has motorcycle oil in it and not regular motor oil.

It probably says "energy conserving" on the top of the 10-30 car oil and that means it has moly in it which can ruin a bike's clutch. Never use an "energy conserving" oil. Most any 10-40 will not have the moly in it but read the top to be sure.

apbling wrote: Now, alot of people have been talking about the diesel rotella T. Is that what you are referring to?

That's very good oil, a lot of people run it. But you can use castrol GTX, valvoline, or just about any decent 10-40 as long as it is not energy conserving. If it is blacking up the oil quickly, just change more frequently for a while.

Make sure the oil has enough ZDDP in it (at least 1000 ppm) or your cams will wear too much. Many bike oils have enough, some don't, but any oil that says "SN" on it basically has no ZDDP in it. I think "SM" has a little but not enough. If you have oil which doesn't have ZDDP in it, you can get additives to put in. A can of STP oil treatment will raise ZDDP enough but also raises viscosity about 4 points.

I can't say that my clutch feels any different but shifting is a lot smoother and requires less effort when I have fresh oil.

I always noticed the clutch engagement was smoother with new oil.

The Rotella has a very good amount of zddp. Toyota now reccomends that in the reman program . The older engines need it to have good cam bearings stay in good shape for a longer period of time. Also the Rotella and Castrol have done extremly well under hi temp applications. Just my 2cents!

The oil I had in there was plain on shell oil. My dad uses it in his service pickup trucks, and he definitely does not spring for anything fancy for those old roaches.

Around here I can get motorcycle oil for about the same price as any of the other oils. Since the shop is near my work I have just been using the Honda GN4 or whatever they call it.