Draining GT550 crankcase via SRIS valve ports

[vdavidoff]

I have done a lot of searching here and found that on my GT550, if I want to drain extra fuel/oil from the crankcase, I should remove the SRIS valves as the 550 has no other crankcase drain bolts.

I did this yesterday and a notable amount of stuff flowed out unassisted from all 3 ports. Pretty typical looking I think - a thin fuel/oil mixture. I also placed some shop towels (the blue disposable ones) in front of the ports and kicked the motor (ignition off) to blast out some more (which is also how I rescued one of the SRIS filters that came off in the crankcase when I was removing the valve).

My question now is, should that be good enough to get out any excessive oil/fuel in the crankcase, or do I need to use something to suck out what else I can? I found one person mentioning that they did this, but nothing indicating if it's necessary.

If it matters, there are 3 reasons I decided to do this.

1. As far as I know the bike had been in various stages of sitting and being tinkered with for years before I got it running, and I hadn't yet attempted to drain the crankcase
2. The bike seems to run excessively rich when it's cold, even after tinkering with all the normal things, and it seemed like excessive fuel in the crankcase might cause this (?)
3. I am getting a notable amount of oil/fuel mixture dripping out of the little drain ports in the exhaust pipes (at the lowest part of the pipes) when the bike is running and shortly after it's shut off. This is heaver to the oil side than what came out of the SRIS ports. I get a little drip from the two inner pipes, none from the left pipe, and a considerable amount from the right pipe (which is also missing its baffle, if that comes into play). This may be is due to the fact that the bike isn't being ridden for long distances right now, but is being started for short periods of time regularly (not enough time for cold start exhaust gunk to burn off?). Not sure. The exhaust is also just plain old and might have crap in it that isn't going to burn off. Again, not sure if that's likely.

I realize those 3 bullets could indicate a wide variety of issues unrelated to crankcase build up. Just though they might be useful to know.

Thanks.
Andy

[stroknsmokngt]

You need to ride the bike to get the engine & exhaust hot enough to burn the oil off, running for short periods of time will cause oil/fuel to build up. I would remove all the baffles and ride it around, after riding the bike and the R/H muffler still smokes then you may have a bad crank seal. Is oil that is dripping from the exhaust clean or black and nasty?

[vdavidoff]

Thanks for the reply. Can you explain how a worn crank seal would cause excessive smoking? I am not familiar enough with the crankcase to understand the details.

(update) After doing more research, I am guessing that a bad seal might cause extra smoking due to transmission fluid getting sucked into the crankcase and into the right cylinder? There was a significant puddle under the bike this morning (again, from the exhaust drain ports), which unfortunately is new (something seems worse). However I don't think what I'm looking at has transmission fluid in it. I guess I need to do a leak down test to be sure.

As far as what's dripping out, it's mostly fuel and the oil is fairly black, but it doesn't look to me to be burnt or particularly nasty. It's definitely far more dirty than what's in my tank, though. This is my first 2 stroke though, so when I think of nasty oil my only point of reference is in an automotive application.

Thanks again.
Andy

[vdavidoff]

Ugh, well, I guess my original question about draining the crankcase still applies, but I've got big problems now. Started the bike this morning and oil was basically flying out of the drain holes in the exhaust. See the attached picture, which is a puddle about 6 inches in diamater that formed after maybe 5 minutes of running. I guess this is probably a clear indication that I have a crank seal failure?

Andy

[stroknsmokngt]

Does the oil smell like 2 stroke oil or gear box oil? Have you had to add oil to the gearbox after running the engine?

[vdavidoff]

Thanks for the replies.

What I smell in the mixture is mostly fuel. I can't tell what oil is most prominent because of the overwhelming fuel smell, which makes me think I might also have a carb issue, though that'd be new too. The bike has been started in cool/cold weather and not ridden, so that'd explain the water I guess.

Anyway, I built a leak down tester using instructions I found here and just finished testing. I am not 100% confident in the results only because I have never done this before, but I followed the instructions and none of the cylinders held. I even sprayed all the ports I had plugged with a soapy water solution to make sure I wasn't getting leakage there. Each cylinder behaved in the same way. They'd hold ~6psi for 10 seconds, then the gauge on the pump would start falling until it hit 0 after about 6-8 seconds.

Because I am relatively confident that my problem is the crank seals, and because I'd like the experience of replacing them, I'm going to go ahead and do the work. If I find that the crank seals look okay, then I guess I'll just consider my test procedure invalid and assume my problem is something else (or a combination of things).

Andy

[Coyote]

Did you plug the SRIS lines? Remove them from the crankcase and replace them with bolts and sealing washers. Try your test again.

[vdavidoff]

Coyote,

I plugged the SRIS valves by removing the line and placing over it a piece of line that has one end blocked off with jb weld. However, I just realized that as I was working through the cylinders, I wasn't reattaching the lines after testing each. Meaning, the SRIS intake port on a cylinder might have been running off a line that wasn't hooked into a SRIS valve on the other end, when I was testing. Sounds to me like if nothing else, I need to redo the test making sure all the SRIS intake ports (up at the cylinders) are either plugged or are connected to a SRIS valve.

I managed to break the non-fouler/valve stem doober I was using, so I need to redo that before I try again.

Andy

[vdavidoff]

Just to close the loop here (for now) - Coyote, I took your advice and plugged the SRIS ports with bolts and sealing washers. I then redid the test making sure to keep the SRIS intake ports plugged, too. The cylinders held better than previously, but still didn't come near holding 6psi for 6 minutes. The middle cylinder came closest, but was at about 2psi after 6 minutes.

As possible as it is that something is still screwy with how I'm doing this test, I feel confident that I'm doing everything I know how to do to make the test valid. I'm going to move forward with replacing the crank seals, since I don't mind having the experience anyway. I guess I'll see what's really up when I get in there. I'm also taking this opportunity to do a bunch more clean up of the case, frame, etc, so that'll be nice.

I guess I'll let you guys know what I find once I open the case.

Thanks again for all the advice.
Andy

[Coyote]

One other thing Andy. It is possible that the air is escaping out the SRIS lines that go into the intake venturi. You could easily check this by placing the open end of the lines in a glass of water. If you get bubbles, you will need to pinch off the open ends with a small pair of vice grips or similar.

[vdavidoff]

When you say "intake venturi" are you talking about where the lines from the crankcase attach to the cylinders? If so, I did plug those for my most recent test, and confirmed they weren't leaking. If not, can you explain where you're talking about?

On a related note, I started pulling stuff off the motor today to get it ready to come out of the frame, and noticed that the oil injection lines were full of air. They definitely weren't when the bike was shut off to start testing. Does this mean air was escaping out of the valves in the oil octopus, and if so, does that mean those valves are broken? Seems like those valves should be able to handle way more than 6psi?

Andy