Do you think I damaged my engine?

[stephenspann27]

A week ago I bought a '89 Katana 750 not running that had the carbs pulled off of it. It hadn't seen the road since 2001. After working on the carbs a week I finally got it running on Weds. It fired right up, I let it idle maybe a minute, blipped the trottle maybe 2-3 time to about 4 grand. I cranked it probably 3 or 4 times and did the same thing. It ran for probably a total of 10 minutes, but with a few minutes between each running. (I don't have the tank on it and I was filling the carbs by pouring gas into the fuel lines, that should tell you how short of a time I was running it). I knew the oil in the had to be old, and I figured, gunky, and that's why I didn't run it much. All the running it did was in nuetral, and the motor never really got very warm.

Now to the point. I pulled the drain plug yesterday about and 5qts of an odorless (slighty gas like smell) fluid came out almost all at once. It was a thin as water, and was not slick at all. I don't know if this is 10yr old oil.. or some kind of diesel or gas? I've never seen old oil look like this.. usually it just get thick and black. It ran out of the motor as fast as water would have.

I filled it up with 10w 40 and ran it a few minutes.... I plan to change the oil a few more times before I even think about riding it.

I know the little bit it ran couldn't be good for it.. but I'm thinking since there was no load on the motor, and it didn't run long enough to get hot, maybe no damage was done?

[kevin2502000]

It was a combination of old oil and gas in the oil from fuel dumping into the crankcase. I had done the similar thing and hadn't caught the problem till an oil change. I think you will be fine, just do as you said change the oil again and replace with a good synthetic for best protection. Make sure your carbs are now working properly so it still doesn't dump fuel into the crank. Most like the carbs were full of gunk and sticking the floats or needle valve from closing. Monitor the situation and you should be fine.

[Slofuze]

+1

Those '89 750 engines are bulletproof.

[RyanR]

Threadjack: (1999 600)
So my bike was not ridden for a month, due to ignition problems. When I ran it again, I put it in prime and ran in for a few hundred miles because it would only run in prime. After I figured out why I could only run in prime (vacuum line on petcock), I fixed that and then read about how the gas could flow into the oil pan… The bike was running noticeably rougher than normal during this period of time (~400 miles on the highway at 6k)

I did an oil change as soon as I could, and noticed similar problems described above, where the oil smelled like gas and was like water. Also, it was clearly low on oil since I didn’t fill up the jug all the way.

The bike still has a bad vibration at about 6k rpm’s, and gets slightly less gas mileage (used to get about 50mpg hwy, now only about 45). Is this engine done for? What could I have ruined?

[akarob]

If gas leaks into the case, it will happen whether it's set to prime or not. It happens because your float needle valves are not sealing shut. Start by fixing that.

[katanarider]

When I first bought my bike I knew nothing about Katanas. The day I bought it the previous owner cranked it up to show me it ran. He had the petcock on prime the whole time. Gas was dripping out of the air filter box drain spout. I assume he rode it some with it on prime. I later found the vacume line disconnected. Anyway, I bought the bike and took it to a bike shop for repairs. The mechanic took if for a ride, a hard fast ride too. He got back and said you have a oil leak but since it was so late in the day he said he would check it in the mourning after the bike cooled off. I assume the bike ran hot? The next day he called me and told me he drained the oil and said the crank case had 8 quarts of oil and gas mixture.
Well, my bike runs fine now. I had my float bowls cleaned and what ever else the mechanic did, sync or blah, blah, blah. If my bike can take that sort of abuse then yours should be fine. My bike had 23,000 miles at the time and it nows has 27,500. Those miles aren't exactly easy grand pappy driving miles either. I drive it hard at least one or two pulls every time I ride it.