RM 250 injested some water

[1998RM250]

RM 250 ingested some water

Hey guys I just picked up another RM 250 today, and took it out to do some riding... Went through this little puddle that ended up being deeper than i thought and sucked some water in the cylinder. I changed the crank oil, pulled the plug and kicked it over quite a few times and sprayed alot of WD 40 in the cylinders then kicked her some more... I then checked for spark and put the plug back in, but it just wont fire up! I'm worried some dirt might have been sucked though as well since it was a really muddy/sandy mess I got stuck in... I was worried for a min that I lost compression seeing how easy it kicked over, but i pulled the plug back out and kicked it over to get all the wd40 out and it seems alright. What should I do at this point, and what would happen if there is dirt in the cylinder? Thanks guys... :bang:

 

[1998RM250]

Well good thing I haven't started it... Took a good listen and it sounds like there is dirt inside the head. Does the whole jug need to come off to clean it out, or can I just pull the top of the head? I've rebuilt a top end before, but its been about 10 years. Any tips would be greatly appreciated, I just bought the bike today =[

 

[IndyMX]

I'd do a complete tear down.

If you don't get whatever is in there out of the crank bearings and rod bearings, you're going to have to split the cases anyway. At considerably higher cost.

 

[1998RM250]

I'm going to pull the head off the bike tomorrow and clean it out good. As for the crank I will change the oil every few days to flush any contaminants out hopefully... Any other advice, I'm very upset seeing I just bought it earlier today!?!

 

[IndyMX]

You obviously don't really understand 2 stroke bikes. First thing you should do, get a service manual. You need to understand the basics of how that bike runs before you start working on it.

There's no oil you can change every few days to flush out the crank bearings.

The crank bearings and bottom end of the piston (wrist pin, con rod bearings and all) are lubricated thru the premix.

By changing your transmission oil you won't do anything to help the bottom end of the engine.

So.. Do like I suggested, and tear it down properly, and clean it thoroughly, or you will most likely have to replace the crank, bearings, con rod, wrist pin and seals. Not to mention the good possibility that you'll need to either have the cases welded or replaced from the chunks of broken con rod blasting thru them.

 

[1998RM250]

I have a basic understanding, all I needed was a refresher... Thanks!

 

[rmc_olderthandirt]

Did you have an air cleaner on when you dropped into this puddle?

I would have expected the air cleaner to strain the water and keep the debris out. If you have some debris in there then there is a good chance that it is parts of your engine, not dirt from the outside.

I have flooded a number of two stroke engines and have always lucked out. I have been able to simply dry the engine out and start them back up. You must do this soon after the flooding, however, as water sitting around for a few days in places it didn't belong will wreck havoc on the internal engine parts.

In all the cases where I have flooded an engine, however, the engine was either off or at low power. If you were "on the pipe" trying to get through that puddle when it sucked water then all sorts of damage could have occurred. Since water won't compress the piston going up or down (two strokes) will come to a sudden stop when it encounters water. This can break pistons, rods or even the crank. On a two stroke is is possible that the intense back pressure can destroy the reeds on the pistons down stroke.

If you have compression and don't have any other reason to suspect piston damage then I would suspect that you still have some water down in the lower end. You might also have water in the carburetor.

Here is what I would do:

Take the gas tank off, and drain the gas out of the carburetor. Note: draining the carb is optional, it will do it on its own in the next steps, but you may not like where it drains to....

Pull the plug.

Turn the bike upside down. Yep, flip it over and let it rest on the handlebars. This will allow any water in the bottom end to drain out through the spark plug hole.

Crank the throttle wide open, hold it there (the bike resting on the grip will probably hold it).

Put it in first gear. This will allow you to spin the rear wheel by hand to crank the engine over. Lots easier than the kick starter.

Spray a lot of WD-40 in the carburetor as you turn the rear wheel. You want it to be running out the spark plug hole.

Let is sit upside down for a few hours to get as much as possible to drain out. While you are waiting, drain a bit of gas out of the tank into a clear jar to check for water.

Turn it back right side up, put it back together, try starting it again.

Rod

 

[1998RM250]

There was a foam filter on it, but i noticed after the bottom of it was ripped and there was some sand in the carb... If you kick it over really slow you can hear a gritty noise coming from the cylinder. I might go pull the tank now, and turn her upside down and spray loads of wd40 into it hoping I can "flush" all the crap out... If not looks like I am going to have to pull the jug off to clean and hope for the best. If there is any dirt deposits on the cylinder, will it eventually burn off and get blown out or am i screwed?

 

[2strokesrock]

No it will not blow it out without seveer engine damage If there is anything in there you are going to have to take it all apart otherwise you will probably ruin your cylinder walls besides on a two stroke it is not vary difficult to take it apart.

 

[_JOE_]

If there is sand in the engine you need to split the cases, period. Not doing so is potentially a fatal mistake.

Even if you have a brand new air filter on it won't trap dirt in water. The water surrounds the dirt and keeps it from sticking to the oil.

 

[1998RM250]

Well we towed the bike behind my buddies jeep and she fired up... I let it warm up and rode it around for a bit then drained the oil out. There appeared to still be a tiny bit of water in the bottom, but I'm letting it all drain out now. I figure I will change the oil on it a couple more times in the next few hours of riding. Thanks for the help...

 

[IndyMX]

Well we towed the bike behind my buddies jeep and she fired up... I let it warm up and rode it around for a bit then drained the oil out. There appeared to still be a tiny bit of water in the bottom, but I'm letting it all drain out now. I figure I will change the oil on it a couple more times in the next few hours of riding. Thanks for the help...

Again, the OIL in that bike does not have anything to do with the crank, bearings, con rod or wristpin...

You can change the oil all you want, that's not going to flush anything out of your crankcase. Just the trans.

 

[jake760]

Well we towed the bike behind my buddies jeep and she fired up... I let it warm up and rode it around for a bit then drained the oil out. There appeared to still be a tiny bit of water in the bottom, but I'm letting it all drain out now. I figure I will change the oil on it a couple more times in the next few hours of riding. Thanks for the help...

I really think you should have pulled the cylinder and flushed the bottom end.