Jump to content
Sign in to follow this  

CR125 Coolant In Engine

Recommended Posts

Hi guys, I have a 2003 CR125 that leaked coolant around the cylinder head bolts. I replaced the cylinder head gasket and it no longer leaks, but when I had it apart the was about a quarter inch of coolant in the cylinder above the piston. There was also a ton in the head pipe when I took it off. I tried to get as much of the coolant out as possible. After putting it back together it starts but only runs for a moment then dies. So my question is if it's likely that my bottom end is flooded with antifreeze? And if it is, would I need to split my cases and clean everything? I'm worried about hydro locking the engine and breaking something. Thanks.

Share this post


Link to post
Share on other sites

Yeah there is a good possibility that there is anti freeze in the bottom end. You can try taking the engine out and flushing the bottom end out with diesel fuel. Has the antifreeze been in there for awhile? I don't know for sure if the water could start forming some rust on the bearings or not. I'm sure someone else has gone through this and can provide a better answer. Does the bike fire back up again right away after it stalls out?

Share this post


Link to post
Share on other sites

I have a 2001 Honda CR125 and just went threw the exact same problem. Change your plug. It's probley Soaked in antifreeze. Pop a fresh BR9ES in that baby and go riding!

Share this post


Link to post
Share on other sites

Well shit then lol but on another note about your first post there about having to split the case and clean everything. That is not needed. Just drain the oil. Then dump in quite a bit of oil and slowly work the kick starter so the oil gets mixed around lots then drain it again. And do that a few time then put the drain plug in and put in about double the amount of oil you need and again slowly work the crank and everything that's stuck to the crank an the covers and case will all get mixed into the oil then drain it once again and put the proper amount of oil back in it.

Just so that way the bike is flushed very well.

Share this post


Link to post
Share on other sites

Man, I wish. Just put in a fresh BR9ES and no luck. But yeah the old plug was completely soaked.

so as of right now what is the bike doing?

Share this post


Link to post
Share on other sites

It starts up for a second, but only every few kicks. When I kick it over I don't hear any water or splashing sound as some have reported. Just doesn't want to stay running. The bike was running strong before this, always started on the first kick. 

Share this post


Link to post
Share on other sites

How does the piston/cylinder look? Was the head gasket blown? Your cylinder head may be warped, allowing coolant to seep into the combustion chamber...

thats a good Possibility.

It starts up for a second, but only every few kicks. When I kick it over I don't hear any water or splashing sound as some have reported. Just doesn't want to stay running. The bike was running strong before this, always started on the first kick.

when it does start are you able to keep it running? Like by giving it throttle?

Share this post


Link to post
Share on other sites

Maybe I should take the head off again, but from what I could tell there was no warping. It hasn't leaked at all since the new gasket. When I had it apart the piston looked fine and compression is good. Head gasket was cracked because one of my cylinder head bolts came off allowing air in . This let coolant into the cylinder. 


Can't keep it running even with some throttle. It runs a second longer if I pop start.

Share this post


Link to post
Share on other sites

Maybe I should take the head off again, but from what I could tell there was no warping. It hasn't leaked at all since the new gasket. When I had it apart the piston looked fine and compression is good. Head gasket was cracked because one of my cylinder head bolts came off allowing air in . This let coolant into the cylinder.

Can't keep it running even with some throttle. It runs a second longer if I pop start.

how is it dying out? Like is it starting up then just bog right out or does it just gradually die out?

If you don't mind make a video of you kicking it over and how it dies out and then I can get a better idea of what's happening.

Share this post


Link to post
Share on other sites

Dies out immediately, 2 seconds tops.

have you gone over all of the basic things that it could be? Like air filter, dirty carb or clogged jets?

Share this post


Link to post
Share on other sites

And if none of this works your best bet is to go threw the entire engine. Check out your timing your cylinder walls your crank. Piston. Rings. Also looking into if the problem is electrical. Your CDI could be failing or your starter or magneto.

Share this post


Link to post
Share on other sites

Yeah I checked on all the obvious things, it was running perfectly not long ago so the problem definitely has to do with the coolant being somewhere it shouldn't be. I know I'm very low on coolant since most of it leaked, there wouldn't be any reason it's not running just because the level is too low would there?

Share this post


Link to post
Share on other sites

Yeah I checked on all the obvious things, it was running perfectly not long ago so the problem definitely has to do with the coolant being somewhere it shouldn't be. I know I'm very low on coolant since most of it leaked, there wouldn't be any reason it's not running just because the level is too low would there?

no that wouldn't be the cause. I'm clueless right now with this problem.

Share this post


Link to post
Share on other sites

No the bike will still run with no coolant. Why would you not top it off after replacing the head gasket? You have to drain the system when you take the head off anyways. Secondly this is a two stroke so the trans oil is separate from the crankcase/crankshaft. Draining the oil will do nothing. Did you take the cylinder off? How do you know the piston and ring look good if you didn't? After reading all this I'm leaning towards a blown top end. It got hot from no coolant and seized up. The cooled back down and is now free, but the engine is still seized. You saying it runs a bit longer after push starting it is a tell tale sign of low compression and a bad top end. Either buy a service manual and study it before you go ANY further or take it to a professional.

Share this post


Link to post
Share on other sites

Well shit then lol but on another note about your first post there about having to split the case and clean everything. That is not needed. Just drain the oil. Then dump in quite a bit of oil and slowly work the kick starter so the oil gets mixed around lots then drain it again. And do that a few time then put the drain plug in and put in about double the amount of oil you need and again slowly work the crank and everything that's stuck to the crank an the covers and case will all get mixed into the oil then drain it once again and put the proper amount of oil back in it.

Just so that way the bike is flushed very well.

 

Where is this drain plug that allows you to fill and drain oil from the bottom end of the engine?  The gear box is sealed from the engine, so if that is what you are thinking, that won't help with any coolant that may or may not be in the bottom of the engine.

Share this post


Link to post
Share on other sites

Where is this drain plug that allows you to fill and drain oil from the bottom end of the engine? The gear box is sealed from the engine, so if that is what you are thinking, that won't help with any coolant that may or may not be in the bottom of the engine.

drain plug is at the bottom of the engine and fill cap is on the right side of the bike and the oil check bolt is on the right side below the fill cap near the bottom of the crank cover.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×